
Peanut allergy: where do we stand?
John Weisnagel, M.D.
- This review of the complex issue of peanut allergy was started
in Oct. 1998 following a great deal of attention given to the
subject in the media at that particular time. This coincided with
many publications in the medical literature as cited in the
references seen below in the opening paragraphs, conclusions of
the authors considered as "alarming, frightening", according to
comments of some visitors scanning this article. There were
articles in magazines, like Time, Newsweek, as well as in local
papers on what seemed an increase in peanut allergy, on banning
peanuts in schools or on commercial flights,
etc.22,25.
Some of the articles, and reactions to them, were posted and
appear in the article, and may still be accessible (at times,
they're removed without any warning). The effect of all this
attention to peanut allergy resulted in a panic situation, both in
the minds of the public as well as the medical community, an
attitude that seems to persist.
-
- Since then, things have quieted somewhat particularly in the
media, but most publications on the subject in the medical
literature will often begin with statements such as, "most
pediatric allergists agree that the prevelance of food allergies,
and peanut allergy in particular, is increasing..."107
or "peanut and nut allergy is common and the most frequent
cause of severe or fatal reactions to foods..."108
or "...despite the steady advancement in our understanding
of atopic immune responses and the increasing number of deaths
each year from peanut anaphylaxis...119
" or..."peanut is one of the most common foods causing
allergic reactions and is the most common cause of fatal and
near-fatal food-related anaphylaxis.."122
all giving the impression that peanut allergy is indeed on
the increase, but as Dr Hugh Sampson states in the opening
paragraph of his article "What should we be doing for children
with peanut allergy?"107
"appropriate epidemiological data to substantiate this belief
are lacking! "
-
- Recent publications on peanut allergy also note that
anaphylaxis has also increased in a very substantial
way.....e.g.169,
or Peanut Allergy: a growing problem, a commentary by
Wesley Burks, published in the J. Clin.
Invest.173
He starts off his article with "Peanut allergy is one of the most
serious of the immediate hypersensitivity reactions to foods in
terms of persistence and severity and appears to be a growing
problem." citing Sampson's 2002 article published in the
N Eng J Med.154,
but as mentioned by Gideon Lack, et al, in their March
13th, 2003 New England Journal of Medicine article
entitled 'Factors Associated with the Development of Peanut
Allergy in Childhood'..."The apparent increase in the
prevalence of peanut allergy has been difficult to explain,
although it parallels an overall increase in allergic diseases in
childhood."171
- Yet, in the J Allergy and Clin
Immun, March 2003 issue, Kelso et al. report on a case
of Psychosomatic peanut allergy. A 27-year old woman with a
history of rhinitis and asthma, 20 min. after eating a peanut
butter and jelly sandwich, developed generalized itching and
hives, shortness of breath and wheezing, treated in the ER. The
next day she had a similar reaction after eating a peanut butter
candy. She was evaluated in the allergy clinic and both skin tests
to peanut (also done with fresh peanut) and peanut-specific IgE
were negative. She had an open challenge with a teaspoon of peanut
butter and in fifteen minutes she complained of itching and
feeling warm, developed hives, but no signs of asthma; she was
treated with epinephrine and fexofenadine. Further tests failed to
show any IgE binding. She underwent a double-blind,
placebo-controlled challenge which was negative. She was informed
of the results and subsequently had an open challenge which was
also negative.172
(posted Mar 31st, 2003)
-
- But the good news is that there are encouraging indications,
contrary to previous publications, that allergy
to peanuts can disappear. There are studies in progress in
various centers evaluating the duration of this allergy, always
thought of as a lifetime allergy. Of some concern though are
recent reports of recurrence
of the allergy in children who have outgrown peanut
allergy with increasing peanut-specific IgE levels and
allergic reactions, for some reason in children who have eaten
peanut sparingly since their negative challenge. (posted Feb 16th,
2004)
- A factor that is being studied is tthat peanuts in the western
countries are for the most part roasted - roasting
peanuts seems to increase their allergenicity and could
be an important element in the prevalance of this allergy.
(see more on this further in this article)
-
- This ongoing article is updated regularly, as developments
occur, hopefully not only to make everyone aware of this
unpredictable allergy, but also to help ease the fear generated.
All updates appear with the date of the posting and for a time
(usually 3 months) preceded by this image
.
(text possibly too technical in references that follow is altered,
and comments added for general public access)
Background
Peanut (arachis hypogea) belongs to the biological family
'leguminosae' or 'legumes' which include peas, beans, lentils,
vegetable gums as acacia and tragacanth, and licorice. Peanut is not
a nut (although publications originating in the United Kingdom often
include it when discussing nut allergy). Nuts belong to different
biological families, e.g. pecan belongs to the 'judanglacea' family
along with walnut, e.g. almond is of the 'drupacea' family which
includes peaches, apricots, plums, nectarine and cherries, e.g. the
'anacardiacea' family groups cashews, pistachios and mangos, etc.See
description in Allallergy.net
and also: "Fruits
called Nuts" with super photos.
According to the National
Peanut Board which represents 25,000 peanut farmers in the US,
americans consume more than 600 million pounds of peanuts and over
700 million pounds of peanut butter annually. Because of its
nutritive value, particularly a good source of protein, peanut today
is a common food in most westernized countries.
The natural history of food allergy involves the development of
the sensitivity and eventual loss of it, as observed in children as
well as adults. Very young children with allergy to milk proteins,
soya, or eggs, tend to lose their allergies as they grow older
7,
26
even in the case of anaphylactic reactions (severe allergic reactions
requiring emergency treatment; detailed further in the article)
27.
However, with certain foods such as tree nuts, shellfish and
peanuts, things are different. According to Bock and Atkins,
children with allergy to peanuts tend to keep their allergy for many
years 19.
In 1995, at the Annual Meeting of the American Academy of
Allergy, Asthma and Immunology, Bock and collaborators presented
their findings in the follow-up of 60 children with confirmed allergy
to peanuts, aged between 3 months and 17 years. They concluded
that:
- 1) Peanut allergy occurs with surprising frequency in
young children: 17 before age one; 30 between one and two
years of age; 19 between two and three years of age; and 3
between three and four years of age;
- 2) children do not seem to lose peanut allergy very
often;
- 3) accidental reactions are common;
- 4) reactions in young children may require emergency
Rx.
Characteristics of
peanut allergy
-Peanut allergy is characterized by more severe symptoms than
other food allergies and by high rates of symptoms on minimal
contact. In a questionnaire study of 622 self-reported allergic
subjects, a total of 406 patients (66%) reported symptoms on contact
with peanut. Only 121 (19%) had been knowingly exposed to peanut
before the first documented reaction implying a high frequency of
occult sensitization.2(see
important facts further in this article re early
sensitization).
-Alt, Ramesh, and Reisman presented a paper
at the 1997 American Academy of Allergy, Asthma and Immunology
(AAAA&I) Annual Meeting, on anaphylaxis in a 6 month old infant,
after eating a portion of a cracker containing peanut. No previous
exposure to peanuts, but a RAST test showed a very high
sensitivity to peanut! (RAST stands for "radioallergosorbent
test", an allergy test done on a sample of blood, the aim as with
skin tests, to check for allergic sensitivity to specific
substances.)
-Approximately one third of emergency-room visits for
anaphylaxis may be due to peanut sensitivity 8,15
-Immediate hypersensitivity to peanuts is a frequent cause of
anaphylactic reactions and deaths in children and adults
3
-Severe allergic reactions caused by foodstuffs have been reported
in Sweden since 1993, 60 cases, five of them fatal, occurring during
the first 3-year period. More than 70% of all reactions reported
were caused by peanuts, soya beans, nuts or almonds. In only 13%
of reported cases were the patients over 17 years of age...with
extremely severe reactions including asthma.4
-In the Sept 1998 issue of Clinical and Experimental Allergy, Moneret-Vautrin, and coll. reported an evaluation of 142 observations of allergy to peanuts in France 23. The clinical features were:
- atopic dermatitis [eczema] (40%)
- angioedema (37%)
- asthma (14%)
- anaphylactic shock (6%)
- digestive symptoms (1.4%)
-Rance F and Dutau G, co-authors of the Sept 1998 article above, published in April, 1999, "Peanut hypersensitiviy in children" which appeared in Pediatr Pulmonol Suppl. and reported the following:
- of 132 pediatric cases of peanut hypersensitiviy, aged between 6 months and 15 years, confirmed by food challenge, more than half were diagnosed before age three.
- the most common symptom was atopic dermatitis (43.1% of cases). Others were: hoarseness (34.8%), asthma (13.6%), anaphylaxis (6%), gastro-intestinal symptoms (1.5%), and oral syndrome [itchy mouth, lips, throat] (0.7%).
- all patients had positive skin tests, with a mean wheal diameter of 8mm (range: 2 to 25mm); wheal diameter was significantly smaller in the youngest children (mean 4.5mm for children < 1 yr of age).
- peanut-specific IgE concentration was < 0.75 IU/ml in 16 cases (14.3%), the mean for the entire group being 30.9IU/ml (range: 0.75 to 100 IU/ml).
- food challenges were not performed in three of the children with a history of anaphylaxis.
- labial food challenge [simple contact of food with lips] was positive in 85 cases (64.8%)
- an oral food challenge was carried out in 45 children (34.3%) and the mean reactive dose was 850 mg (range: 1 mg to 7gm).
- labial food challenge with peanut oil was positive in 2 cases of 50 tested (4%) and 17 of 63 children (29.9%) tested by oral food challenge were also found to be sensitive to peanut oil.
- half the children were also allergic to other foods, as demonstrated by food challenge (53.7%) or to airbone allergens (62.8%).
The authors conclude: Hypersensitiviy in the very youngest children raises questions about how sensitization occurs. Diagnosis was confirmed by food challenge. Peanut products are very difficult to eliminate from the diet because of inadequate labeling of food products. An ELISA test, available in a number of countries, can be used to detect peanut in foods (as reported above). 61 (posted April 5th, 1999)
- -In the Dec. 1999 issue of the Anaphylaxis Network Newsletter, there was an article by Dr. Wesley Burks,University of Arkansas, on food anaphylaxis. It mentioned partway through that "It is not rare, particularly for peanut-allergic children who had minimal cutaneous (skin) and gastrointestinal symptoms as young children, to experience significant systematic anaphylactic symptoms following the ingestion of peanuts in their adolescent years." (brought to my attention by Nancy Wiebe of the Calgary Allergy Network and posted Jan 23d, 2000).
-
-
- -According to Sicherer and Sampson, in their review "Peanut and tree nut allergy" published in the Dec. 2000 issue of Pediatrics, "Allergies to these foods are common, frequently have an onset in the fist years of life, generally persist, and account for severe and potentially fatal reactions. Furthermore, the ubiquity of these foods in the diet makes avoidance difficult and accidental ingestions, with reactions, common." 101 (posted Dec 10th, 2000)
-
-
-
-
- -Kanny, Moneret-Vautrin, Flabbee and collab. published their epidemiological study entitled"Population study of food allergy in France" in the July 2001 issue of J Allergy Clin Immunol. The study was conducted on 33,110 persons who answered a questionnaire addressed to a sample of the French population. 1129 persons with food allergy selected during phase I received a second questionnaire. Results:
- the reported prevalence of food allergy is 3.52%: 3.24% evolutionary and 0.12% now asymptomatic due to avoidance of the food, and 0.17% cured.
- 80% were city dwellers
- 63% were female
- 11% were health-care workers
- 57% presented with atopic diseases
- food allergy was often persistent, lasting more than 7 years in 91% of the adults
- most frequent allergens:
- rosaceae (peach, plum, pear, cherries, apple) fruit sensitivities in some pollen sensitive individuals 14%
- vegetables 9%
- milk 8%
- crustaceans 5%
- fruit cross-reacting with latex 4%
- tree nuts 3%
- peanut 1%
- food allergy was 4 times more frequent in patients with latex allergy
- the main manifestations of food allergy were:
- atopic dermatitis for children under 6 yrs of age
- asthma for subjects 4 and 6 yrs of age,
- anaphylactic shock in adults over 30 yrs of age. Shocks were correlated with alcohol or non-streroidal anti-inflammatory drug (NSAID) intake.
- The authors conclude that the prevalence of food allergy is estimated at 3.24% in France, the study emphasizing the increasing risk of food allergy in well-developed countries, drawing attention to certain risk factors, such as the intake of drugs (NSAID, beta-blockers, and angiotensin-converting enzyme inhibitors) or alcohol, intolerance of latex gloves, and socio-professional status.128 (posted July 31st, 2001)
-
-
- -"Food anaphylaxis is now the leading known cause of anaphylactic reactions treated in emergency departments in the United States. Is is estimated that there are 30,000 anaphylactic reactions to foods treated in emergency deparments and 150 to 200 deaths each year. Peanuts, tree nutes, fish, and shellfish account for most severe food anaphylactic reactions...the mechanistic details responsible for symptoms of food-induced anaphylaxis are not completely understood, and in some cases, symptoms are not seen unless the patient exercises within a few hours of the ingesion." (Sampson HA) 177(posted June 25th, 2003)
-
-
- -Sperget JM et al, in the Feb 2004 Ann Allergy Asthma Immunol have a comment entitled Correlation of initial food reactions to observed reactions on challenge. After a retrospective review of all food-sensitive children who underwent food challenges at the Children's Hospital of Philadelphia in a 5 year period, they concluded that "Patients will typically experience similar reaction on re-exposure to the initial reaction. However, multiple-organ system reactions can occur after any initial clinical presentation, with milk, egg, and peanut having more multiple-organ reactions than other foods." 216(posted April 25th, 2004)
-
Threshold
doses
-The minimum dose of food protein to which subjects with
food allergy have reacted in double-blind, placebo-controlled
food challenges is between 50 and 100 mg. (double-blind and
placebo-controlled signify that neither the patient nor physician
know whether the food or a placebo [substitute] is being
used [food evaluated and a substitute both appear the
same], and a control non allergic individual also participates
in the challenge) However, subjects with peanut allergy often
report severe reactions after minimal contact with peanuts, even
through intact skin. In a group of well-characterized , highly
sensitive subjects with peanut allergy, the threshold dose of
peanut varies. As little as 100 microg. of peanut provoke symptoms
in some subjects with peanut allergy10
-In the April, 2001 issue of Allergy ,
Dr Jonathan O'B Hourihane, in his paper entitled The
threshold concept in food safety and its applicability to food
allergies, states that "many factors may contribute to a
variation of threshold in an individual exposed to an allergen
during the course of his or her daily life....the most
important one of these is the adequate training and awareness of
manufacturers and caterers who aim to provide safe and nutritious
meals to their allergic and non-allergic customers
alike....Studies have not yet had the power to investigate
whether peanut allergy is more commnonly associated with very low
dose reactivity than other foods. This means that industry must
not concentrate only on peanut and tree nuts when looking at
issues of contamination just because they are associated with the
majority of severe reactions. There are more milk and egg
allergic children in the general population and they deserve the
same protection from allergy exposure as sufferers of peanut or
tree nut allergies. 118
(posted April 21st, 2001)
-In the Jan 2002 J Allergy Clin Immunol ,
twelve clinical allergists and other interested parties published
their conclusions following a Sept 1999 roundtable discussion. The
article is entitled Factors affecting the determination of
threshold doses for allergenic foods: How much is too much?
They define the threshold dose as "the amount of
the offending food that would elicit mild objective symptoms
(e.g. mild urticaria, erythema, and oral angioedema, in the
most sensitive individual." Many factors may be involved in
the reactions reported such as circumstances of exposure, the
amount and type of food eaten, determined anecdotally. For
peanut, based on challenges, the lowest provoking dose was 1mg
(in 4 out of 309 patients) the range being 1mg to 5 gms.
Results: Considerable data were identified in
clinical files relating to the threshold doses for peanut,
cows' milk, and egg; limited data were available for other
foods, such as fish and mustard.
Conclusions: Because these data were often obtained
by means of different protocols, the estimation of a threshold
dose was very difficult. Development of a standardized
protocol for clinical experiments to allow determination of the
threshold dose is needed. 148
(posted Feb. 11th, 2002)
-Follow-up to the above publication: A consensus protocol
for the determination of the threshold doses for allergenic foods:
how much is too much? was published in the May 2004
Clin Exp Allergy by the same group (plus others).225
(posted May 22nd, 2004)
- -The distribution of individual threshold doses
eliciting allergic reactions in a population with peanut
allergy is the title of a publication in the Dec
2002 J Allergy Clin Immunol by Wensing et al.
Twenty-six adult patients with a convincing history of
peanut-related symptoms, a specific IgE level of 0.7kU/L, or
greater, or a positive skin prick test response of 2+ or
greater to peanut were included. These patients underwent
double-blind, placebo-controlled food challenges with
increasing doses of peanut.
- Results: Threshold doses for allergic reactions ranged
from a dose as low as 100 µg up to 1 gm of peanut
protein. Fifty percent of the study population already had
an allergic reaction after ingestion of 3 mg of peanut
protein.
- Conclusions of the authors: A substantial part of a
population with peanut allergy will react to very low
amounts of peanut, requiring accurate declaration of peanut
content in consumer products. This is even more important
because patients with severe reactions react at lower doses
than patients with mild symptoms. 167
(posted dec 9th, 2002)
-
- -Determination
of no-observed-adverse-effect levels (NOAELs) and eliciting
doses in a representative group of peanut-sensitized
children is the title of a publication in the Feb. 2006
J Allergy Clin Immunol by Flinterman et al. As the
abstract states: 'Current labeling practices for allergenic
foods like peanut can be inadequate. For future regulatory and
industry guidelines, information on NOAELs and eliciting doses
(ED) for allergenic foods is necessary.' They evaluated a group
of 27 children by questionnaires, skin prick test,
determination of specific IgE, and DBPCFC (challenges) with
peanut according to the international consensus protocol, with
9 doses ranging from 10 µg to 3 g peanut flour. Dietary
management was evaluated over a 12 month period.
- Results: 22 children (81%) had a positive challenge. The
NOAEL in this group was 1 mg peanut flour, corresponding to 2
mg whole peanut. The ED for subjective symptoms was 100
mg to 3 gm. Severe reactions occurred only at high doses.
EDs were not correlated to previous reactions by history,
skin test, or specific IgE levels. All patients with a
positive challenge were advised to follow a strict diet. During
the follow-up period, 10 patients had a less strict diet
likely containing traces fo peanut. In 3 cases, a mild reaction
occurred with food products laeled "may contain peanut".
- Conclusion: The NOAEL in a representative group
of children with peanut allergy was 2 mg,. Dietary
compliance in half of this group was inadequate.
257(posted May 7th, 2006)
-At the 59th annual meeting of the American
College of Allergy, Asthma, and Immunology Nov. 2001 in
Orlando, Florida, Dr Rosemary Hallet presented a study of a
questionnaire involving people with known food allergies, "Have
you ever had a reaction after touching food?" 'People with a nut
allergy can have an anaphylactic reaction if they kiss someone who
has recently eaten the offending substance, according to Dr
Rosemary Hallet. '...we found 5% who voluntarily stated that
they had had a reaction after kissing someone who had eaten a type
of nut to which they were allergic. The reaction is likely
more common than we found'. Fifteen of 442 respondants stated that
they had a reaction, even up to 6 hours after the kisser had eaten
the offending food.(But there's no description of the reaction in the report). (posted Nov. 25th, 2001)
Dr Hallett has a letter to the editor of the New
England Journal of Medicine, in the June 6, 2002
issue, entitled, Food Allergies and Kissing where she
specifies that the implicated foods were peanuts, walnuts,
and other tree nuts; reactions began rapidly after
the kiss in all interviewed subjects (all in less than a
minute); all 17 reported localized itching and swelling
or urticaria in the area kissed; four subjects reported the
development of wheezing with at least one episode of
kissing; patient 5 was kissed on the cheek by his mother
right after she tasted pea soup on the stove and a large wheal
immediately developed at the exact site of the kiss, followed
in minutes by flushing, urticaia, angiodedema, and severe
wheezing, requiring the administraion of epinephrine in the
ER. (posted June 21st, 2002) 156
-In the Sept 2001 issue of Allergy, Wathrich,
et collab. published an artilce entitled "Kiss-induced
allergy to peanut" which is probabley similar.
Unfortunately there is no abstract on Medline. 138
(posted Nov 23d, 2001)
- -Here's a report of a telephone survey done by a Swedish
group, reported by Nils E Eriksson (co-ordinator) Lung &
Allergy Clinic, County Hospital, Halmstad, Sweden: CAN
KISSES INDUCE ALLERGIC SYMPTOMS IN MORE THAN TEN PERCENT OF
FOOD ALLERGIC PATIENTS? A total de1139 patients (56
children < 8 years and 1083 patients > 8 years
responded and the authors' results confirm that approx. 10%
of allergic individuals can react by being in close
proximity to peanuts or kissing someone who has eaten
peanuts, although their tables summarizing the results are
difficult to interpret exactly. (I have not found said study
on Medline).
-Kiss
may have killed Quebec teen (posted Nov 28th, 2006). This
has been reported
throughout the world, but unfortunately without further
info regarding the victim. Following a
CBC report (only in French) it seems her boy-friend had
eaten a peaut butter sandwich many hours before and he was not
aware of his girl-friend's peanut allregy. She was also
asthmatic and at 3 am, she thought she was having an asthma
attack and began using her puffers without success. The Epipen
was discovered only after Urgence-Santé got to the
victim's residence. Was the peanut allergy-kiss responsible
for the anaphylactic reaction? (posted Nov 30th, 2005)
- -The latest on this story is that the autopsy
revealed that it was in fact a tragic death related to a
reaction to peanut.
- -On
March 3d, 2006, Dr Michel Miron, coroner of the
district of Chicoutimi, speaking to the media, concluded
that 'Christina Desfornes did not die due to an
anaphylactic reaction after kissing her boyfriend after
he had eaten peanut butter. The story made headlines
round the world, and Mr. Miron said he wants people to
know that a peanut-butter sandwich did not cause the
death of Christina Desforges last November.
- -On May 11th, 2006, Dr Miron held a press conference where he concluded that Christina Desforges did not die as a result of an allergic reaction to peanut, but from cerebral anoxia due to an acute asthmatic attack.
- PS. Unfortunately, as happens usually following corrections or retractions, the initial report back in Nov 2005, which made headlines worldwide, for many will stand and be wrongfuly treated as a death due to peanut allergy.
- -At
the 2006 annual meeting of the AAAA&I held in
Miami, FL Mar 3-7th, Maloney JM et al reported Peanut
allergen exposure through kissing (saliva). Assessment and
intervention. (J Allergy Clin Immuno, vol117, no2,
abstracts, #134, p S34) The authors concluded that
peanut allergic patients, particularly adolescents, must be
counseled regarding the risks of kissing someone who has
recently eaten peanut, even if they brushed their teeth.
Practical advice may include brushing teeth PLUS waiting
a number of hours before kissing, but definite
recommendations must follow evaluation of cleaning routines
that are underway in a larger population. (posted April
15th, 2006)
- -The authors published their findings in the J Allergy Clin Immunol 2006 Sep;118(3):719-724. Epub 2006 Jul 24. Of the 38 individuals, most (87%) subjects with detectable peanut after a meal had undetectable levels by 1 hour with no interventions. None had detectable levels several hours later after a peanut-free lunch. Waiting several hours and ingesting a peanut-free meal were more effective at reducing salivary peanut protein concentration than simple, immediate interventions. (posted Sept 19th, 2006)
-Swelling of lips and tongue were reported in a card player
from cards he handled which were contaminated by peanuts eaten by
fellow players. Lepp U, Zabel P, Schocker F. Playing
cards as a carrier for peanut allergens. Allergy
2002 Sep;57(9):864.
- -Morisset M, Moneret-Vautrin D, et al in the Aug 2003
Clin Exp Allergy published Thresholds of clinical
reactivity to milk, egg, peanut and sesame in immunoglobulin
E-dependen allergies: evaluation by double-blind or single-blind
placebo-controlled oral challenges. Data from 125 positive
oral challenges to egg, 103 to peanut....were analyzed. The
lowest reactive threshold has been observed at less than 5 mg of
peanut....They conclude: Minimal reactive quantities show
that, in order to guarantee a 95% safety for patients who are
allergic to peanut...and on the basis of consumption of 100 g of
food, the detection tests should ensure a sensitivity of 24 p.p.m
for peanut. 190
(posted Aug 18, 2003)
- -In the Nov 2003 Clin Exp
Allergy, Grimshaw K et al. have a study entitled
Presentation of allergen in different food preparations
affects the nature of the allergic reaction - a case
series. In an ongoing study that used a double-blind
placebo-controlled food challenge to investigate peanut allergy
and clinical symptoms, the observed reaction severity in four
of the first six subjects was greater than anticipated. They
hypothesized that this was due to differences in the
composition of the challenge vehicle. Peanut-allergic subjects
were re-challenged with a peanut preparation containing less
fat. Results: 3 of 4 subjects reacted to much smaller
doses of peanut protein on re-challenge (mean dose quivalence -
23 times less peanut) with the lower fat recipe. RAST
inhibition and ELISA tests concurred.
- Conclusion: The fat content of a challenge vehicle has a
profound effect on the reaction experienced after allergen
ingestion. This is another factor to be considered in assessing
the risk of certain foods to food-allergic consumers and adds
another dimension to clinical, research and regulatory
practice. 195
(posted Nov 22nd, 2003)
-
- -At the annual AAAA&I Meeting held in San Francisco
Mar 19-23, 2004, Conover-Walker and Wood have a poster
entitled The Risk of food challenges.. Chart review was
performed on children who underwent food challenges to milk,
egg, peanut, soy and/or wheat in a university based pediatric
allergy clinic over a seven-year period: Of the 570
challenges completed, 238 (42%) experienced an allergic
reaction. Failure rates were:
- egg 50/130 (38%), milk 88/162 (54%), peanut 65/157 (41%),
soy 21/76 (28%), and wheat 14/45 (32%).
- 121 (51%) had a reaction involving 1 organ system (egg 50%,
milk 51%, peanut 45%, soy 62%, wheat 64%),
- 90 (38%) had 2 system involvement (egg 34%, milk 40%,
peanut 46%, soy 24%, wheat 22%), and
- 27 (11%) had 3 system (skin, gastrointestinal, and
respiratory) involvement (egg 16%, milk 9%, peanut 9%, soy 14%
and wheat 14%).
- No patients experienced hypotension.
- All reactions were reversible with diphenhydramine
+/&endash; epinephrine and corticosteroids. No children
required hospitalization and there were no deaths.
- Conclusions There are risks associated with food
challenges and the risks are similar for each of the foods
studied. One half of the reactions involved only 1 organ system
and only 11% involved 3 organ systems. Given the benefits that
result from a negative challenge, these risks are reasonable
when challenges are performed under the guidance of an
experienced practitioner in a properly equipped setting.
211(posted
Feb 16th, 2004)
-
-
-
- -Update on threshold doses of food allergens: implications for patients and the food industry is the title of a publication in the June 2004 Curr Opin Allergy Clin Immunol by Moneret-Vautrin and Kenny. The purpose of their review was to bring the reader up to date on the importance of assessing a food's lowest observed adverse-effect level (LOAEL) with two aims. Firstly, to help industry choose tests with a level of sensitivity capable of detecting food allergens hidden in industrial products. Secondly, to specify protective measures for highly allergic individuals in order to prevent recurrent severe anaphylaxis.
- SUMMARY: Concerning IgE-dependent food allergies, the
threshold dose inducing symptoms is now known to vary a great
deal according to the individual. A reactive dose of less than
65 mg characterizes16 and 18% of patients allergic to egg or
peanut... 1% of these patients have a very low threshold, about
1 mg. Such data emphasize the necessity of using detection
tests with a sensitivity better than 10 parts per million. The
modifications of allergenicity undergone by protein ingredients
that are now commonly introduced into industrially made
products are not yet sufficiently known. A better knowledge of
the reactive doses of these proteins is needed.221
(posted May 15th, 2004)
-
-At the 2006 Annual Meeting of the AAAA&I in
Miami,.FL., Dr Marie-Noel Primeau from the Allergy Service of Ste
Justine Hospital, Montreal, presented First reaction to nuts or
peanuts from candy bars labelled 'may contain nuts/peanuts' in
older chidren. ( J Allergy Clin Immuno 117:no 2
abstracts, no 146, page S 37) She described the case of a 13
yr-old boy who had his first anaphylactic reaction (abdom. pain,
urticaria and respiratory distress) requiring treatment with
epinephrine 30-60min. following a dinner containing a brownie
labelled 'may contain traces of nuts'. Skin tests were positive to
hazelnut, cashew and pistachio and negative to peanuts. An oral
challenge with hazelnut was positive. He had no previous history
of allergy to nuts. The second case involved a 5 yr-old boy who
developed urticaria 15 min. after eating a granola bar containng
almonds and labelled 'may contain traces of peanuts.' He was a nut
eater but had never eaten peanuts. Skin tests were negative to
nuts but positive to peanuts. An open challenge to almonds was
negative, but parents refused a peanut challenge. Two yrs later
his skin test was still positive to peanuts, but the RAST was
negative. One hour after an open peanut challenge the patient
developed rhinitis and a severe cough.
- Conclusion: A first allergic reaction to nuts and
peanuts may happen after ingestion of products labelled 'may
contain traces of nuts/peanuts' in older children.
(posted April 15th, 2006)
Related to the above presentation:
-In the Arch Pediatr. 2006 Jul 5, Feuillet-Dassonval C, Agne PS, Rance F, Bidat E. have an rticle entitled, [Which avoidance for peanut allergic children?]. According to the abstract: 'The benefits of a strict avoidance diet seem limited: reactions to the low doses and to the peanut oil refined are rare and most often slight. It is not proven that a strict avoidance facilitates the cure of allergy. On the other hand, strict avoidance could induce a worsening of allergy, with deterioration of quality of life, creation of food neophobia. In case of cure of allergy, it is difficult to normalize the diet after a strict avoidance. Outside of the rare sensitive patients to a very low dose of peanut, for which a strict avoidance is counseled, the report benefits risk is in favor of the prescription of adapted avoidance to the eliciting dose. For the majority of the peanut allergic children, it seems to us that the avoidance can and must be limited to the non hidden peanut.'260 (posted July 15th, 2006
- See more on this subject in the section on "follow-up
of patients with peanut allergy" further in this
article.
Prevalence or
incidence of food allergies
The exact prevalence of food allergy, specifically peanut
sensitivity, is not known. Reports vary. Here are a few going back a
few years:
-The incidence of food allergy in children is
approximately 1.3% and among adults 0.3% according
to Chandra (1997). 5
-True food allergies are much less prevalent than is generally
believed. They are more common in infants and children under
age three than in older children and adults. Infant colic
generally is not caused by a food allergy. In infants, urticaria,
eczema or gastrointestinal bleeding may be due to foods such as
milk and eggs, but clinical tolerance usually develops within a
few years. Peanuts, tree nuts, seafood and seeds, as well as milk
and eggs, can cause anaphylaxis in highly allergic children, and
re-exposure to such foods presents the risk of life-threatening
reactions7.
-Approximately 5% of children younger than 3 years and 1.5% of
the general population experience food allergic disorders,
indicating that about 4 million Americans suffer from food
allergies 11.
-A dichotomy exists between perceived food allergy and that
confirmed by appropriate challenge procedures. Only 40% of
suspected food allergy has been confirmed by double-blind,
placebo-controlled food challenges. . .In a recent survey of 5000
American homes, the percentage of individuals reporting peanut
allergy was 7.2% 16.
-Allergy to peanuts represents 28% of food allergies and
occurs under 1 year of age in 46% of cases, under 15 years of age
in 93% 23.
-Ewan reported on 62 cases of peanut
and/or nut allrergy evaluated in a one year period. Peanuts
accounted for nearly half of the allergies, with 55% of the
allergies presenting by age 2 years and 92% by age 7
years.33.
-Here's a publication that just may change our perception of
peanut and nut allergy somewhat. The April 1999 issue of the
J Allergy Clin Immunol contains an article by Sicherer,
Munoz-Furlong, Burks and Sampson entitled "Prevalence of peanut
and tree nut (TN) allergy in the US determined by a random digit dial
telephone survey."65The
title may sound nondescript, but read on- the findings are very
significant:
- A total of 4374 households contacted by telephone participated
(participant rate, 67%), representing 12,032 individuals.)
- Peanut or TN allergy was self-reported in 164 individuals
(1.4%). . . the prevalence of reported allergy in adults (1.6%)
was higher than that found in children under 18 years of age
(0.6%).
- In 131 individuals, details of the reactions were obtained.
When applying criteria requiring reactions to be typical of
IgE-mediated (allergic) reactions (hives, angioedema, wheezing,
throat tightness, vomiting, and diarrhea) within an hour of
ingestion, 10% of these subjects were excluded.
- Among the remaining 118 subjects, reactions related to:
peanut (58), walnut (24), cashew (8), Brazil nut (8), almond
(7), pecan (7), hazelnut (3), Macadamia nut (2), unspecified mixed
nuts (6) (Only four [all adults] reported both peanut
and TN allergy, and 5 reported reactions to more than one TN).
Allergic reactions involved:
- 1 organ system (skin, respiratory, or gastrointestinal
systems) in 50 subjects (42%),
- 2 in 45 subjects (38%),
- and all 3 in 23 subjects (20%).
- Forty-five percent of these 118 respondents reported more
than 5 lifetime reactions. . .
- 51% had other food allergies
- 35% had atopic dermatitis (eczema)
- 34% had asthma
- 33% had allergic rhinitis. . . [94% of the subjects
reported at least one of these atopic diseases (eczema, asthma
or rhinitis.]
Conclusions: Peanut and/or tree nut allergy affects
approximately 1.1% of the general population, or about 3 million
Americans, representing a significant health concern. Despite
the severity of reactions, about half of the subjects never sought
an evaluation by a physician, and only a few had epinephrine
available for emergency use.
Two observations of this study were novel:
- First, only 4 subjects (all adults) reported allergy to
both peanut and at least one tree nut. Previous studies in
patients referred for allergy evaluations reported reactivity
to tree nuts in 20% 33
and 34 % 13
of patients with peanut allergy.
- The second novel finding was that these allergies were more
common in adults than in children because the general
prevalence of food allergy is usually greater in children (7%)
than in adults (1% to 2%) 11.
Because peanut and tree nut allergies are usually not
outgrown17
12,
there may be a greater representation among adults, a
population that has accumulated affected individuals.
- Additional comment:
- -While the study was only a random telephone survey, done
by a standardized questionnaire, by a professional group
(Innovative Medical Research, Inc (Towson, Maryland), the
findings are different than previously reported, and seem less
alarming. (posted April 12th, 1999)
- -Comment
on Doctor's Guide on Internet, by Anne Munoz-Furlong
(posted May 6th, 1999)
-
-
-
- -"Up to 8% of children less than 3 years of age and
approximately 2% of the adult population experience food-induced
allergic disorders. A limited number of foods are responsible
for the vast majority of food-induced allergic reactions: milk,
egg, peanuts, fish, and tree nuts in children and peanuts,
tree nuts, fish, and shellfish in adults. Food-induced
allergic reactions are responsible for a variety of symptoms
involving the skin, gastrointestinal tract, and respiratory tract
and may be caused by IgE-mediated (allergic) and non-IgE-mediated
(or non-allergic) mechanisms. . .the skin and respiratory tract
are most often affected by IgE-mediated food-induced allergic
reactions, whereas gastrointestinal disorders are most often
caused by non-IgE reactions. . . The initial history and physical
examination are essentially identical for one or the other, but
the subsequent evaluation differs substantially. Proper diagnoses
often require screening tests for evidence of food-specific IgE
and proof of reactivity through elimination diets and oral food
challenges. Once diagnosed, strict avoidance of the implicated
food or foods is the only form of treatment. Clinical tolerance to
food allergens will develop in many patients over time, and
therefore follow-up food challenges are often indicated."
71,
72 (posted June 23d, 1999)
-
-In Pediatr Allergy Immunol. 2006 Aug;17(5):356-63, Venter C et al have a publication entitled Prevalence of sensitization reported and objectively assessed food hypersensitivity amongst six-year-old children: a population-based study. This population-based cohort study recruited 798 6-year-olds resident on the Isle of Wight (UK). Sensitization rates, reported rates of FHS and objectively assessed FHS was established using food challenges. A total of 94 (11.8%) 6 yr olds reported a problem with a food or food ingredient. The rate of sensitization to the pre-defined panel of food allergens was 25/700 (3.6%). Based on open food challenge and/or suggestive history and skin tests, the prevalence of FHS was 2.5% (95% CI 1.5-3.8). Based on double-blind challenges, a clinical diagnosis or suggestive history and positive skin tests, the prevalence was 1.6% (95% CI 0.9-2.7). The rates of perception of FHS are higher than the prevalence of sensitization to main food allergens and the prevalence of FHS based on food challenges. Milk, peanut and wheat were the key food allergens amongst those with positive challenges.
This study confirms the results of a 2005 publication by the same group done amongst adolescents: Prevalence of sensitization to food allergens, reported adverse reaction to foods, food avoidance, and food hypersensitivity among teenagers. J Allergy Clin Immunol. 2005 Oct;116(4):884-92. (posted Oct. 3d, 2006)
-
Statistics
-Food allergies, particularly to peanuts,
are a common cause of anaphylaxis. Here are some
statistics:
- Approximately 125 people die each
year in the
USA
secondary to food-induced anaphylaxis. . . Anaphylaxis is
recognized by cutaneous, respiratory, cardiovascular, and
gatro-intestinal signs and symptoms occuring singly or in
combination80
(posted Aug. 12th,
1999)
- In Canada: According to
Statistics Canada, there were 6 deaths due to food anaphylaxis
in 1997 and 8 in 1998 in Canada (posted Oct 29th, 2000)
- Attempts to obtain from Statistics Canada figures for
subsequent years were unsuccessful because coding of
deaths following WHO guidelines at this point in time cannot
specify any deaths caused by anaphylaxis whether related to
foods or other causes. (posted Jan 23d, 2004)
- In the UK, according to
Pumphrey (Clin Exp Allergy 2000
Aug;30(8);1144-50) from the 20 fatal reactions
recorded each year, 5 are due to food.100
(posted Dec 6th, 2000)
- See below, articles by Macdougall CF
- In France, according to
Le
réseau d'allergovigilance,
by Gisèle Kanny, Médecine Interne, Immunologie
Clinique et Allergologie, Hôpital Central 54035 Nancy cedex:
there were 107 reported cases of serious anaphylactic reactions
due to food allergy in 2002 (in 33 children and 74 adults),
including two fatalities due to soy and peanut. (see the
presentation in pdf format, unfortunately only in French). (posted
Oct 3d, 2003)
- The original artilce was published in
the Revue Française d'Allergologie et d'Immunologie
Clinique Vol 43. No 9 (2003): Anaphylaxie
alimentaire sévère et léthale: cas
rapportés en 2002 par le réseau
d'allergovigilance (Morisset et al.)(Pre-lethal and lethal
food anaphylaxis: cases reported by the French national
allergovigilance network)
- The prevalance of food allergy in
the French population is estimated to be 3.24%.
- Anaphylactic shock was reported in
59.9% of the cases involved (one fatal to peanut), other
systemic reactions: 18.7%, laryngeal oedema:15.9%, serious
acute asthma: 5.6% (one fatal, to soy),
- The most frequent allergens were:
peanut (14), nuts (16), shellfish (9), latex-fruit group (9),
lupine flour (7), wheat flour (7), celeri (5), snails (5)
200.
(posted Dec 14th. 2003)
- This study was also published in the
Feb. 2004 Allerg Immunol (Paris) : Severe food
anaphylaxis: 107 cases registered in 2002 by the Allergy
Vigilance Network. The authors conclude "Setting up such a
network in other countries would lead to a significant advance
in knowledge of the peculiarities of allergies....The aims are
to record cases of severe anaphylaxis, to establish an
epidemiological data bank from prospective multicenter studies,
and to monitor the allergic risk of novel
foods"....217
(posted April 26th, 2004)
- Morisset, Moneret-Vautrin, et Kanny
of the Allergy Vigilance Network , published
Prevalence of peanut sensitization in a population of 4,737
subjects - an Allergo-Vigilance network enquiry carried out in
2002 in Allerg Immunol (Paris) Feb.
2005
- Results classified subjects
into four groups according to the clinical history and
prick-tests to common inhalants: group 1: subjects
suspected of having a food allergy; group 2: subjects
with ongoing atopic disease; group 3: subjects with an
underlying predisposition to atopy, as showed by one or
more positive results to prick-tests with airborne
allergens; group 4: non atopic subjects. The
sensitization rates were 22.7%, 8.7%, 4%, and 0.4%
respectively.
- Assuming that 25% of the
French population is allergic, the rate of sensitization
to peanut in the general population should be between 1%
and 2.5%. Considering a ratio of 3.3 between
sensitization and clinical allergy as plausible, the
prevalence of peanut allergy could be 0.3% to 0.75% of
the French population. This figure is lower than that for
the UK, the US and Canada (0.8% to
1.5%).245
(posted May 9th, 2005)
-
-
- In
Australia,
the risk of a fatal reaction to
food, particularly in pre-school children is remote: an estimated
one fatality in 30 years in the under 5-year-old population and 2
deaths in 10 years in the entire child population.
188
(posted Aug 4th, 2003)
-
- -Bock, Munoz-Furlong, and Sampson, in the Jan 2001
issue of the J Allergy and Clini Immunol report on their
analysis of 32 fatal cases due to anaphylactic reactions to foods,
reported to a national registry, established by the American
Academy of Allergy, Asthma, and Immunology....The 32 could be
divided in two groups: Group 1 had sufficient data to identify
peanut as the responsible food in 14 (67%) and tree nuts in 7
(33%) of cases. In group 2, 6 (55%) of the fatalities were
probably due to peanut, 3 (27%) to tree nuts, and the other 2
cases were probably due to milk and fish (1 [19%]
each)...most victims were adolescents or young adults, and all but
one were known to have food allergy before the fatal event...all
but one were known to have asthma, and most of them did not have
epinephrine available at the time of their fatal reaction.
Fatalities due to ingestion of allergenic foods in susceptible
individuals remain a major health problem. In this series,
peanuts and tree nuts accounted for more than 90% of the
fatalities. Improved education of the profession, allergic
individuals, and the public will be necessary to stop these
tragedies.110
(posted Feb. 13th, 2001)
-
- -A follow-up to this article relevant to the 'national
registry', Sicherer, Furlong, Munoz-Furlong, Burks and Sampson
published in the July 2001 J Allergy and Clini
Immunolo A voluntary registry for peanut and tree nut
allergy: Characteristics of the first 5149 registrants.
(The registry was established through use of a structured
questionnaire distributed to all members of the Food Allergy
and Anaphylaxis Network, and to patients by allergists.
Parental surrogates completed the forms for children under 18
years of age). Here are their findings:
- registrants were primarily children (89% of
registrants were younger than 18 years of age, the median age
was 5 years)
- isolated peanut allergy was reported by 3482
registrants (68%)
- isolated tree nut allergy by 464 (9%)
- allergy to both foods by 1203 (23%)
- registrants were more likely to have been born in Oct. Nov
or Dec.
- the median age of reaction to peanut was 14 months
(first known exposure for 74%)
- the median age of reaction to tree nuts was 36 months
(first known exposure for 68%)
- one half of the reactions involved more than one organ
system
- more than 75% required treatment, frequently from
medical personnel
- registrants with asthma were more likely than those
without asthma to have severe reactions (33% versus
21%)
- in comparison with initial reactions, subsequent
reactions due to accidental ingestion were more severe, more
common outside the home, and more likely to be treated with
epinephrine.
Conclusions: Allergic reactions to peanut and tree nut
are frequently severe, often occur on the first known exposure,
and can become more severe over time. 126
(posted July 27th, 2001)
-
- -Furlong, Desimone and Sicherer, again related to the
registrants in the US Peanut and Tree Nut Allergy Registry,
published in J Allergy Clin Immunol Nov
2001 "Peanut and tree nut allergic reactions in
restaurants and other food establishments." ..."features of
allergic reactions to peanut and tree nut in restaurant foods,
and foods purchased at other private establishments, e.g. ice
cream shops and bakeries. Results: details obtained from 156
episodes (29 first-time reactions) form 129 subjects/parental
surrogates.
- -most reactions were caused by peanut (67%) or tree nuts
(24%)
- -in 9% of the reactions, a combination of peanut and a nut
or peanut and unknown allergen
- -symptoms began at a median of 5 minutes after exposure and
were severe in 27% of reactions
- -overall, 86% of reactions were treated (antihistamines,
86%; epinephrine, 40%.)
- -establishments cited: Asian food restaurants (19%) ice
cream shops (14%) and bakeries/doughnut shops (13%)
- -among meal courses, desserts were a common cause
(43%)
- -of 106 registrants with previously diagnosed allergy who
ordered food specifically for ingestion by the allergic
individual:
- -only 45% gave prior notification about the allergy to
the establishment.
- -for 83 (78%) of these 106 reactions, someone in the
establishment knew that the food contained peanut or tree
nut as an ingredient.
- -in 50% of these incidents, the food item was "hidden"
(in sauces, dressings, egg rolls, etc), visual
identification being prevented.
- -in 23 (22%) of the 106 cases, exposures were reported
from contamination caused primarily by shared
cooking/serving supplies.
- -in the remaining 21 subjects with previously diagnosed
allergy, reactions resulted from ingestion of food not
intended for them, ingestion of food selected from
buffet/food bars, or skin contact/inhalation (residual food
on tables, 2; peanut shells covering floors, 2; being within
2 feet of the cooking of the food,1)
-
Conclusions: Restaurants and other food estblishments pose
a number of dangers for peanut-and tree nut-allergic individuals,
particularly with respect to cross-contamination and unexpected
ingredients in desserts and Asian food. Failure to establish a
clear line of communication between patron and establishment is a
frequent cause of errors." 136
(posted Nov 7th, 2001)
-
-In the Dec 2001 issue of Allergy appeared the
following article by Shafer et al: Epidemiology of food
allergy/intolerance (FA/FI) in adults: association with other
manifestations of atopy. Of the 1537 studied subjects, 20.8%
reported FA/FI. Nuts, fruits, and milk most frequently led to
adverse effects, and the sites of manifestations were oral
(42.9%), skin (28.7%), gastro-intestinal (13%), systemic (3.2%),
and multiple (12.2%). Skin tests to 10 common foods and 9
aeroallergens were done: one quarter (25.1%) were sensitized to at
least one food allergen, hazelnut (17.8%), celery (14.6%),
peanut (11.1%) accounting for most of the positive
reactions. Food-allergic subjects (positive history and
sensitization to corresponding allergen) suffered significantly
more often from urticaria, asthma, atopic eczema, and especially
hay fever (73.1%) than controls. Conclusions: FA/FI in adults
is frequently reported and associated with other manifestations of
atopy.
141 (posted Jan 14th, 2002)
- -Woods, Stoney, and coll. published in the Jan 2002
Eur J Clin Nutr Reported adverse food reactions
overestimate true food allergy in the community. Based on skin
tests, only 7 out of 457 adults (aged 26-50 yrs) who
reported illness to a food also had a positive skin test to that
food, suggesting that most reactions are not due to IgE mediated
food allergy.
149
(posted Mar 6th, 2002)
-
- -Woods and coll. also published Prevalence of food
allergies in young adults and their relationship to asthma, nasal
allergies, and eczema in the Feb. 2002 Ann Allergy
Asthma Immunol. Out of 1141 adults (aged: 20-45 yrs) taken at
random and evaluated (questionnaire, history of asthma and other
allergic conditions, lung function tests, and skin tests to cow's
milk, peanut, egg white, shrimp and wheat), only 1.3% had
probable IgE-mediated food allergy. Those with probable IgE
peanut and shrimp allergy were significantly more likely to have
current asthma and doctor-diagnosed asthma.150
(posted Mar. 6th, 2002)
- -Fatal
food allergies- rare in children. BBC News report. Monday, 25
March, 2002, 01:53 GMT . Researchers from Newcastle General
Hospital calculate that if 5% of children in the UK have a food
allergy, the risk of that child dying because of it would be 1 in
800,000 a year. In 10 years, there were just eight deaths.
They hope their findings, published in the journal Archives
of Disease in Childhood, will reassure parents worried that
rates of such reactions are increasing dramatically. (posted
Mar 25th, 2002)
- Here is the publication in question: MacDougal
CF, Cant AJ, Colver AF: How severe is food allergy in
childhood? The incidence of severe and fatal allergic reactions
across the UK and Ireland. A retrospective
search for fatalities in children 0-15 years from 1990 to
February 1998 primarily of death certification at offices of
national statistics was done along with a prospective survey of
fatal and severe reactions from March 1998 to February 2000,
primarily through the British Pediatric Surveillance Unit.
- Resultts: The UK under 16 population is 13
million. Over the past 10 years, 8 children died (incidence
of 0.006 deaths per 100,000 children 0-15 years, per year).
Milk caused four of the deaths. No child under 13 died from
peanut allergy...Over the past two years, there were six
near-fatal reactions (none caused by peanut) and 49
severe ones (10 caused by peanut), yielding incidences of
0.02 and 0.19 per 1000,000 children 0-15 years of age per year
respectively. Co-existing asthma is more strongly associated
with a severe reaction than the severity of previous
reactions. (posted April 8th, 2002)151
- Electronic responses to this
article (reproduced here in part):
1. From Jane Salter,
M.D. president of Anaphylaxis
Canada:
- The findings and conclusions of our Canadian perspective on
anaphylaxis (Jane
Salter MD, Saral Mehra1, James T. Cairns MD, Gordon Sussman MD,
Peter Vadas MD PhD A Study of 32 Food-Induced Anaphylaxis
Deaths in Ontario; 1986-2000) differ from those of the
MacDougal CF et al article. The British study found that 8
chldren died from food-related anaphylaxis over a 10-year
period in the UK and Ireland...peanuts /nuts did not seem to
play a significant role even in non-fatal reactions.
- In Ontario, Canada, eleven of 32 food-related deaths
between 1986 and 2000 occurred in children. Unlike the
British study, peanuts/nuts caused 10 of the 11
deaths...The population of Ontario age 0-15 years is
below 2.5 million, less than 20% of the population size sampled
in the British study. The peak age for food-related anaphylaxis
deaths in Ontario was between 15 and 25 years of age. This age
group was excluded from the British survey.
- Given population differences, the lower British/Irish
death rate, particularly for penaut/nut, is
surprising.
- In the British study, patients who responded to one dose
of epinephrine were excluded from the severe reaction
category...this is misleading as it allows treatment success to
interfere with measurement of incidence.
- The study does not underscore the potential life-saving
benefits of early IM administration of epinephrine.
- As it is not currently possible to predict who might
have a fatal reaction, we recommend that all people with
allergies to peanuts, tree nuts and shellfish, regardless of
degree of previous reactivity, be prepared to deal with an
anaphylactic emergency.
- Parents should be reassured that, provided they obtain
an accurate diagnosis and follow current, recommended
guidelines, their children will be well-protected. As teens and
young adults appear to be at greatest risk, early childhood is
the key time to prepare children for the more challenging years
ahead.
-
- 2. From David M. Reading, director of patient
support group, Anaphylaxis
Campaign:
- The authors conclude that the risk of a fatal
allergic reaction among children under 13 is small, and the
inference seems to be that the problem has been vastly
exaggerated.
- No one would argue that parents of food-allergic children
should be helped to lower the anxiety levels in their lives.
But the danger with this report is that it goes too far the
other way and may lead to a dangerous over-confidence among the
families affected by severe allergy and also among doctors,
schools, child carers, and the food industry.
- Medical experts would be better qualified to discuss the
flaws in the study's methodology. As a layman, I would conclude
there appear to be many.
- The authors acknowledge that the risks increase for
teenagers and young adults. Perhaps this is yet another
reason for remaining well-prepared while children are
younger.
- Equally worrying, GPs may become reluctant to prescribe
epinephrine injection pens to children when they genuinely need
them. Having an epipnephrine kit appears to provide an
assurance to patients, parents and child carers alike that they
are not powerless; they have a means to protect
themselves.
- It would be disastrous if this report actually increased
the risks for allergic children by persuading their families -
and those who care for them - that the sensible protective
measures they take are unnecessary.
-
-
3. From S. Allan Bock, Jonathan Hourihane, David
Reading, Pete Smith, David Hill, Gideon Lack, and Anne
Munox-Furlong:
-
- -Although the article by MacDougall et al.
regarding the incidence of severe and fatal reactions to
food would seem to be reassuring,, we would like
to express some concerns and raise some questions about the
data presented.
- -The first question is whether the ascertainment of
cases is really as complete as the authors suggest.
- -...the records acquired as described seem to
represent the same underreporting issues as those in the
US. Is it really unlikely that the BPSU misses a
significant number of cases?
- -A second concern is the reporting of cases only up
to age 15.
- -As mentioned by Dr Slater above, and in
the Bock, Munoz-Furlong, and Sampson study110
, of 32 fatalities, 10 occurred in youngsters up
to age 15. An additional 10 occurred in adolescents
aged 16 to 19. Why did Macdougall et al. not include
all adolescents?
- -A third question must always be raised when fatal
food anaphylaxis is studied: is it not possible that cases
of fatal asthma were actually initiated by unidentified
allergic reactions to food?
- -The trigger responsible for individual asthma
fatalities is not always determined.
- -What about fatalities that never reach the
emergency dept and are misclassified on death
certificates as asthma fatalities?
- -Fourth: the authors' definition of severity seems
incomplete.
- -Individuals with severe food
reactions...often not reported, or
under-reported.
- -Fifth: the issue of the safe administration of
epinephrine.
- -We disagree about the risk to children of
the administration of a single dose of epinephrine as
opposed to withholding that dose...overdosage
certainly may occur, but it seems more likely that an
overdose would be administered by medically trained
personnel rather than by parents. The over
prescription of epinephrine is a debatable issue,
however it seems a small price to pay, with a low
risk, in order to save even one young life.
- -Finally, we are very concerned that families will
interpret this paper to mean that death from food allery is
very unlikely, and therefore they may relax their vigilence.
- -If families of younger allergic children
become less concerned when their children become
adolescents, it may be too difficult to institute a
good prevention education program. This is exactly the
opposite of the goal of education programs in the US
(The
Food allergy and Anaphylaxis Network) and
UK (Anaphylaxis
Campaign)
-
- 4. From Warner JO in his editorial in the June
2002 Pediatric Allergy and Immunology, entitled
How dangerous is food allergy in childhood? he says in
part:
- -"what are the problems with the MacDougal paper?
- The system used by the Pediatric Surveillance
Unit, usually used to study the epidemiology of uncommon
childhood disorders, has never been employed to study
common disease such as food allergy.
- It is quite clear that pediatricians are only one of
many different specialists who might be called on to see
such patients.
- They also employed scrutiny of notifications of
deaths but deliberately excluded asthma deaths. In
fact, it is very likely that a percentage of putative
asthma deaths were due to anaphylaxis....Thus there could
very well be a very considerable underestimate of the number
of deaths.
- The ascertainment through pediatricians
deliberately also excluded children who received only one
injection of epinephrine. The authors chose to deem
'severe' as implying the need for more than one
injection. It is clear, however, that early use of
epinephrine is the key factor in surviving anaphylactic
reactions. The early use of a single dose may well
prevent further progression to life-threatening
problems....two-thirds of individuals resorting to
auto-injector epinephrine do not subsequently present
themselves at hospital but choose to continue their own
management.Thus the representation of severe and
life-threatening reactions may have been under-recorded by
at least 66%.
- The issue as to whether to prescribe auto-injector
epinephrine to an individual who has had an acute
reaction, particularly to peanut....is always difficult
to address...it is not possible to predict future severity
in relation to past experience....it would seem prudent to
err on the side of caution and issue the injector. This
should be coupled with very careful advice on avoidance and
reassurance about the relatively low risk of
life-threatening reaction, particularly in early childhood.
There is also the issue of ensuring that in childhood all
precautions are in place so that by the time the patient
reaches adolescence, where there clearly is an increasing risk
of life-threatening reactions, the individual has full
information and a long-standing cautious approach. Introducing
the concept of caution only in adolescence could be doomed to
failure." (posted Nov 22nd, 2002)165
- Response of the authors: (in part)
-
- As to the accuracy and validity of our data: Did our
paper under-ascertain deaths? We used many sources and spoke
to many experts in the field.
- We specifically studied children up to 15 years of age
because this is the group we were interested in...we wanted
to bring a proper paediatric perspective.
- We are not sure we agree that children, who have
self-administered epinephrine, often do not go to hospital.
However, we do not know the proportion and said as much,
excluding this group from our definition of severity.
- Finally, we agree that education of professionals
and the public should continue based on the best data
available. This must include those parents whose children are
truly at high risk as well as those many parents that think
any immediate hypersensitivity reaction to food means their
child is at high risk of an allergic death; when in reality the
risk, in the absence of asthma, seems vey small.
Different parents will come to different views about how to
proceed faced by a severe but very small risk, just as we all
do in many aspects of our lives. (posted Oct 28th, 2002)
-
-
- 5. A.T Clark and P.W. Ewan responded to the
McDougall et al article in Arch Dis Child
2003;88:79-81 in the Correspondance
section and here are the highlights:
- "McDougall et al... conclude that the risk of death is
small and play down the importance of severe food
reactions. The implication is that epinephrine (adrenaline)
autoinjectors are overprescribed. This paper has serious
consequences for the management of children with food allergy,
so the methodological problems need to be explored to provide a
balanced view. The data produced are likely to be misleading by
underestimating both severe and fatal reactions.
- ...the authors incorrectly assume that all such deaths
will be correctly registered as allergy (or related
terms). Anaphylactic reactions are often mislabelled as
asthma deaths, because of a lack of antecedent history or
information. This is clear from retrospective analysis of
fatal reactions.
- The paper focuses on the tip of the iceberg since their
diagnostic threshold for inclusion was too high. The
diagnostic criteria used are unvalidated, unreferenced, and
irrelevant to clinical practice. To be included as a severe
reaction, they required one or more of the following:
cardiorespiratory arrest, inotropic support, > 20 ml/kg
fluid bolus, more than one dose of epinephrine, and more than
one dose of nebulized bronchodilator. This is ridiculous as
the majority of reactions warranting treatment with
epinephrine- that is, by accepted definition severe (UK
Resuscitation Council) will be missed. Furthermore, a single
dose of intramuscular epinephrine, if given promptly, is
usually effective for the treatment of anaphylaxis - do the
authors not consider anaphylaxis severe? They will
therefore have missed....severe reactions without their
diagnostic criteria, e.g. where epinephrine and/or nebulized
bronchodilator was used once for severe dyspnea, reactions
treated in the community, reactions treated in accident and
emergency departments...
- They state that the incidence of severe food allergic
reactions is 0.19 per 100,000 children per annum, and for
near-fatal (intubated) reactions, 0.02 per 100,000 children per
annum. The fact that 1 in 8 were intubated suggests that
their criteria for severe reactions were inappropriate. That
these figures are an underestimate is shown by compaison with
other data...Sheik and Alvers study: almost four-fold
more,...ALSPAC data: 38-fold more...our East Anglia incidence
of severe nut allergy: 62-fold more than the McDougall et al
study.
- Assessment of severity: Severity varies from trivial
(facial urticaria) to life threatening. We have proposed a
method of assessing severity in peanut and nut allergy which
could be applied to food allergy. Reactions were graded 1-5.
It is important also to consider the amount of allergen
causing the reaction as this is one of the factors determining
severiy. Thus, a patient with a mild or moderate
reaction to trace exposure such as inhalation or contact with a
food containing nuts, might have a severe reaction on ingesting
a small amount of nut. This grading system emphasises
the importance of respiratory symptoms which are known to be
the main severe feature of food allergy. Applying this to
an unselected series of 539 patients with nut allergy, half the
patients have mild, predominantly cutaneous reactions (grade
1-3), 35% have mild airway involvement (grade 4), and 13% have
severe (grade 5) reactions.
- Who needs Epipen? This is the most difficult issue and
there is debate. Many of those claiming Epipen is
overprescribed fail to understand that Epipen should be seen as
part of a complete management package. We do not claim to know
the answer, and this will require extensive data on natural
history and may differ in different allergies....We have
devised a system in food allergy to decide whether Epipen is
required and have used this over several years; those with
grade 4-5 reactions receive Epipen and those with only grade
1-3 reactions do not, but receive oral antihistamines.
There are variations: 1) if the patient has ongoing asthma
of other cause, Epipen is prescribed. 2) If a trace exposure
had caused a grade 1-3 reaction, Epipen is prescribed.
Epinephrine by intramuscular injection is very safe and
there are no reports of deaths in children related to Epipen.
The prescription of Epipen should highlight a child at risk.
Widespread provision of Epipen to all food allergic children
means those at risk are less easily identified and care
diluted.
- Conclusions:
- The McDougall et al paper has identified only the
extreme end of the severe spectrum of food allergic
reactions and this should not be used as the only end point
to inform management.
- The inferences drawn are of little relevance to
clinical practice and are not helpful in deciding which
children require an epinephrine autoinjector.
- While we would agreee that there are not likely to be
many deaths as a result of food allergy in the under 15 age
group, these data should not be used to minimise the problem
or reduce appropriate care.
- There is evidence that an integrated management plan
can significantly reduce further reactions in number and
severity. Management requires accurate diagnosis and
assessment of severity...It should be emphasised that each
child is different and may require different
medication...Provision for epinephrine autoinjectors is only
one part of this and should not be viewed in isolation.
Control of asthma and other allergies is important and
retraining essential. " 168
(posted Jan 31st, 2003)
-
-
- -Mcdougall, Colver, et al. have more stats in their June
2005 Acta Pediatr article, Severe food-allergic
reactions in children across the UK and Ireland, 1998-2000.
Taken from the abstract of the article: ...Whilst food allergy
may be becoming more common, fatal reactions to food in
childhood are very rare and their rate is not changing. A
Prospective survey, 1998 to 2000, of hospital admissions for
food-allergic reactions-conducted primarily through the British
Paediatric Surveillance Unit, covering the 13 million children in
the UK and Ireland.
- Results:
- 229 cases reported by 176 physicians in 133
departments, yielding a rate of 0.89 hospital admissions per
100 000 children per year. Sixty-five per cent were
male,
- 41% were under 4 years.
- Main allergens were peanut (21%), tree nuts (16%),
cow's milk (10%) and egg (7%).
- Main symptoms were facial swelling (76%), urticaria
(69%), respiratory (66%), shock (13%), gastro-intestinal
(4%).
- Fifty-eight cases were severe. Three were fatal, six
near fatal, and 8 of these 9 had asthma with wheeze being the
life-threatening symptom. Three near-fatal cases received
excess intravenous epinephrine. None of the non-fatal reactions
resulted in mental or physical impairment.
- Seven of 171 non-severe and 6/58 severe cases might
have had a worse outcome if epinephrine auto-injectors had
been unavailable.
- Six of the severe cases might have benefited if
auto-injectors had been more widely prescribed.
- Conclusion: In the United Kingdom and Ireland, the
incidence of severe reactions is low. The study highlights
that: asthma is a strongly significant risk factor for a
severe reaction and therefore warrants optimal management;
severe wheeze is a prominent feature of severe reactions
and warrants optimal management; intravenous epinephrine should
be used with great care if needed. Epinephrine auto-injectors
do not always prevent death, but our study design and data
do not allow a definite statement about whether overall they
are beneficial.252
(posted Oct 3d, 2005)
-
-
- See additional stats in the anaphylaxis
section, posted Nov 13th, 2002
-
-
-
-
-
-
- -In Allergy Clin Immunol Int - J World Allergy Org.15/5 (2003), Ebisawa, et al. have a publication entitled Food Allergy in Japan. The authors state, "We do not have any population-based prevalence figures for food allergy in Japan....After WWII, a major change occurred in the dietary habits of Japanese people with the introduction of western food....possibly being the reason for an increase in food allergy in Japan. The most common food allergen among Japanese children is hen's egg, followed by cow's milk and wheat. These three major food allergens account for about 60% of pediatric food allergy. A few new items with increasing frequency of allergic reactions among children are peanuts, sesame, and fruit. (posted Jan 26, 2004)
-
-
-
Personal
statistics coverning the period between Sept. 1992 and Dec.
2001
- -From Sept 1992, Dr Zave Chad, allergist-colleague and good
friend, at the time also in the Allergy Section of Ste-Justine
Hospital, and I decided to use a laptop computer during
consultations, rather than writing long hand in the patient's
chart (most often not legible). An easily legible printed hard
copy was later put in the patient's chart. All patients seen at
the allergy clinic at Ste Justine, as well as those seen at the
office since Sept. 1992 are in a database that after almost 10
years is quite impressive. The beauty of the program used
(FilemakerPro) is that it is very simple to obtain statistics of
all sorts about all these patients, age, date of consultation,
history, allergy tests, diagnosis, treatment, etc. Here is the
first phase of the analysis:
Incidence of peanut allergy:
- total of all patients seen in consultation:
19,020
- children (< 12 years ): 7,164
- adults (12 years & older): 11,856
- number of peanut-allergic patients:
- adults: 126 or
1.06%
- children: 582
or
8.12% (posted Mar.
22nd, 2002)
- NB. These figures do not necessarily reflect an increase in
peanut allergy, but an increase in the number of
referrals for peanut allergy.
-
- See: Retrospective
Study (preliminary results) Powerpoint presentation
(posted April 5th, 2002)
-
-
Sensitization to
peanuts
-possible during pregnancy, probable
during breast feeding:
- The British Medical Journal, June 27th, 1998
published a letter entitled "Women warned to avoid peanuts
during pregnancy and lactation." that came from the Department
of Health, Committee on Toxicity of Chemicals in Food, Consumer
Products and the Environment, Wetherby, North Yorkshire. According
to John Warner, professor of child health at Southampton
University and a member of the government's working group on
peanut allergy, there appears to be a "link between maternal
consumption of peanuts and peanut products and earlier onset and
increasing prevalence of allergy. Evidence from aborted fetal
samples shows that from the second trimester onwards fetuses are
capable of producing an allergic reaction. There are several
theories on how sensitization occurs. Some research shows that
antigens from the mother can cross the placenta, whereas other
work suggests fetuses can swallow IgE from the amniotic fluid,
causing sensitization 31.
- Following the June 27th, 1998,
article in the British Medical Journal, a comment was
published in The Lancet by Pamela W Ewan, July 4th, 1998,
entitled "Prevention of peanut allergy" in which she notes that
the Committee's report said that pregnant women "may wish" to
avoid eating peanuts...she stresses the importance of peanut
allergy as a common cause of anaphylaxis...its prevalence having
increased substantially32
...regarding in utero (during pregnancy) sensitization, there
is a lack of convincing evidence from prospective studies that
manipulation of the maternal diet during pregnancy has a lasting
effect on the development of food allergy. Indirect data suggest
that lactation is a more likely route of primary sensitization,
but this point remains to be established34.
- In the Aug 29th, 1998 The
Lancet, Deborah E Fox, Gideon Lack, as well as Richard S H
Pumphrey, Phillip B Wilson, and Amolak S Bansai, respond to Pamela
Ewan's commentary. The first letter agrees with Ewan's call for
further studies 'so that these public health measures can be
soundly based'...the UK guidelines ..have caused
distress to mothers with peanut-allergic children. In the
second letter authors suggest that the advice of the Committee
be extended to all nuts 35.
In the BMJ 2007;335:633 (29 September), doi:10.1136/bmj.39348.851968.BE, Zosia Kmietowicz has an article entitled Advice to pregnant women to avoid eating peanuts should be withdrawn. Department of Health advice for pregnant women with a family history of atopic diseases to avoid eating peanuts and food that contains peanuts and not to give such food to their children until the age of 3 years is out of date and should be immediately withdrawn, says a report from the House of Lords. The health department advice, which was first issued in 1998 and is repeated in government booklets given to pregnant women and new parents, is totally without evidence, the House of Lords Science and Technology Select Committee heard during its inquiry into allergy in the United Kingdom. 281 (posted Oct 16th, 2007)
- In a Feb 1999 study done in Cape Town, South
Africa79,
it was shown that:
- mothers who consumed peanuts more than once a week
during pregnancy were more likely to give birth to a
peanut-allergic child than mothers who consumed peanuts less
than once a week.
- Peanuts or peanut butter was introduced into the child's
diet from a significantly younger age in the peanut-allergic
subjects.
- There was a positive correlation in the peanut-allergic
subjects between age of introduction of peanuts and age at the
onset of symptoms.
- Exclusive breast feeding did not protect against the
development of peanut sensitization.
- Peanut allergy is associated with an increased risk of
sensitization to other foods. (posted Aug. 6th,
1999)
-
- In the June 2000 of the
Anaphylaxis Network Newsletter, Dr Peter Vadas, past
President of the Anaphylaxis Foundation of Canada, and the Medical
Director of the Regional Anaphylaxis Clinic at St Michael's
Hospital in Toronto, writes in his article on 'The Process of
Sensitization', "A study just completed in my laboratory has shown
that peanut protein does, in fact, pass from the maternal diet via
the bloodstream into breast milk. Using a very sensitive assay for
peanut allergens, we tested samples of breast milk for the
presence of peanut protein at various times after consumption of
dry, roasted peanuts by a group of volunteers. The two major
peanut allergens associated with anaphylaxis were detected in
breast milk within one to three hours after ingestion in
approximately 50% of the volunteers. These data confirm the
previously unproven notion that some infants may become sensitized
by exposure to peanut protein through breastfeeding."
(posted Dec. 30th, 2002)
- The study Dr Vadas refers to has
been published in the April 4th, 2001 issue of the
Journal of the American Medical Association
115
(posted April 14th, 2001)
-
- Dr Vadas continues, "However, the story
is not quite so simple. The concentration of peanut protein,
timing of exposure and frequency of exposure may lead to either
allergic sensitization or to tolerization. The latter process
actually protects against allergies. In some cases, exposure to
peanut protein in breast milk may actually protect against later
development of peanut allergy. At this stage, it would be overly
simplistic to suggest that all lactating women avoid peanut
products during breastfeeding. While this may protect some
children from peanut sensitization, it may predispose other
children to acquiring peanut allergy by preventing the process of
tolerization. Instead, it may be more prudent for lactating
mothers to avoid peanut products while breastfeeding hight risk
infants, namely those who have a strong family history of
allergies or those who already have a first degree relative with
peanut allergy. (posted July 26th, 2000)
-
- The concept of tolerization, or
tolerance, was touched upon by Drs Gideon Lack and Jean
Golding, in their comments regarding Pamela W. Ewing's article
entitled 'Clinical study of peanut and nut allergy in 62
consecutive patients: new features and associations.' BMJ
1996;312:1074-8 (27
April)...."exposure to peanuts and other food allergens
during lactation and childhood may be important in the development
of immunological tolerance and may prevent allergic sensitisation
to these foods...avoidance measures would serve only to reduce
exposure to peanuts to low levels, and this could pardoxically
increase allergic sensitisation to peanuts; low dose exposure
to allergens (rather than high dose exposure) favours production
of IgE, and as little as 2 µg of inhaled allergen a year may
be sufficient to induce allergic sensitisation via the airways."
(posted July 26th, 2000)96
- At the AAAA&I Annual Meeting held in
San Francisco Mar 19-23, 2004, Appelt et al. presented
their findings in an oral presentation entitled Breastfeeding
and food avoidance are ineffective in preventing sensitization in
high risk children. Mothers completely avoided peanuts, nuts
and fish and decreased intake of milk, and eggs during the third
trimester of pregnancy, and while breastfeeding up to one year.
Skin tests were performed in the children at 1, 2 and 7 years of
age. Conclusion: High risk children frequently sensitize to
common foods in infancy but sensitization often resolves to milk
and eggs. Partial food avoidance strategies in the third trimester
and during breastfeeding are ineffective in preventing and may
enhance sensitization to food in high risk
children.218
(posted April 26th, 2004)
- Strid, Thomson, Hourihane et al have a
publication in Immunology, Nov 2004 issue, A
novel model of sensitization and oral tolerance to peanut protein.
Quoting from the abstract, 'The exact route of primary
sensitization is unknown although the gastrointestinal
immune system is likely to play an important role. Exposure of
the gastrointestinal tract to soluble antigens normally leads to a
state of antigen-specific systemic hypo-responsiveness (oral
tolerance). A deviation from this process is thought to be
responsible for food-allergic diseases. In this study, we have
developed a murine model to investigate immuno-regulatory
processes after ingestion of peanut protein and compared this to a
model of oral tolerance to chicken egg ovalbumin (OVA). We
demonstrate that oral tolerance induction is highly dose
dependent and differs for the allergenic proteins peanut and OVA.
Tolerance to peanut
requires a
significantly higher oral dose
than tolerance to OVA. Low
doses of peanut are more likely to induce oral sensitization and
increased production of interleukin-4 ...These results show that
oral tolerance to peanut can be induced experimentally but
that peanut proteins have a potent sensitizing effect. This
model can now be used to define regulatory mechanisms following
oral exposure to allergenic proteins on local, mucosal and
systemic immunity and to investigate the immunomodulating effects
of non-oral routes of allergen exposure on the development of
allergic sensitization to peanut and other food allergens.'
236
(posted Oct. 29th, 2004)
- -At the annual AAAA&I meeting held in San Diego, CA in Feb. 2007, Anne Des Roches et al presented, Peanut Allergy in Infants: Is Breastfeeding a Risk factor?. The mothers of 403 infants, half of which were allergic to peanut (mean age 14 months) were enrolled in the study between Oct 1998 and Jan 2005. They underwent a questionnaire about breastfeedidng, maternal diet during pregnancy and during breastfeeding, infant diet, environmental exposure to peanut and family atopic status.
Their conclusions: Early exposure to low levels of peanut food, as in human breast milk and in utero, seems to be a significant risk factor for the development of peanut allergy in infancy. (Posted May 5th, 2007)
- These findings seem to corroborate those published in the British Medical Journal of June 1998 (John Warner), as well as the commentaries by Ewen, Fox, Lack et al, that were published in The Lancet that same year (all posted above, in this section on 'sensitization'). But since 1998, Dean and Venter published Government advice on peanut avoidance during pregnancy--is it followed correctly and what is the impact on sensitization? J Hum Nutr Diet. 2007 Apr;20(2):95-9. The abstract reads as follows: 'In 1998, the UK government issued precautionary advice that pregnant or breast-feeding women with a family history of atopy, may wish to avoid eating peanuts during pregnancy and lactation. This study aimed to assess the compliance with this recommendation and investigate its impact upon peanut sensitization. METHODS: A total of 858 children born immediately after the advice were followed for 2 years and assessed for peanut sensitization. A standardized questionnaire was used to ascertain history of atopy and maternal exposure to peanuts during pregnancy. Following parental consent children were skin prick tested to assess sensitization to peanuts.
- RESULTS: Sixty-five per cent of mothers had avoided peanuts during pregnancy. Forty-two per cent of the mothers had heard about the government advice, and half modified their diet as a consequence. Neither maternal nor family history of atopy had any significant effect on peanut consumption. Parity did play a role, and mothers having their first child were twice as likely to change their diet (P<0.001). Mothers of 77% of the children sensitized to peanuts had avoided peanuts during pregnancy. In this cohort study maternal consumption of peanut during pregnancy was not associated with peanut sensitization in the infant. CONCLUSIONS: The majority of mothers in this cohort avoided peanut consumption during pregnancy. It is likely that either the government advice is misunderstood by mothers, or that those who communicate the advice have not fully explained who it is targeted at.' (posted May 8th, 2007) 269
- -In the J Allergy Clin Immunol. 2007 May;119(5):1197-202. Epub 2007 Mar 13. Hourhane JO et all. published 'The impact of government advice to pregnant mothers regarding peanut avoidance on the prevalence of peanut allergy in United Kingdom children at school entry'. BACKGROUND: In June 1998, the United Kingdom government suggested that atopic pregnant and breast-feeding mothers and their infants should avoid peanuts. OBJECTIVE: We report the prevalence of peanut sensitization in the first school cohort (2003-2005) to have been conceived after the advice was issued. METHOD: A total of 1072 mother-child pairs were studied in school. Children with positive peanut skin prick test results to peanut had peanut challenges. RESULTS: Overall, 61% of 957 mothers recalled hearing the advice about peanuts in 1998. This figure was unaffected by maternal atopic status. Only 36 mothers (3.8%) followed the Government's advice by stopping the consumption of peanuts while pregnant. Maternal atopy had no effect on peanut consumption while breast-feeding. Mothers were less likely to change their diet if having a second or subsequent child compared with mothers having their first child (odds ratio 0.635, 95% Cis, 0.543-0.743; P < .01). Thirty children (2.8%; 95% CIs, 1.8% to 3.8%) had a positive peanut skin prick test result. Twenty children (1.8%; 95% CIs, 1.1% to 2.7%) were shown to have peanut allergy. This is the highest prevalence for peanut allergy recorded to date. CONCLUSIONS: The prevalence of peanut sensitization in this cohort is 2.8%, and peanut allergy now affects 1.8% of British children at school entry. It is difficult to ascertain any impact (either positive or negative) of the United Kingdom government advice on the prevalence of peanut allergy in British children aged 4-5 years from 2003 to 2005. CLINICAL IMPLICATIONS: It remains uncertain if peanut avoidance during pregnancy and breast-feeding has any effect on the prevalence of peanut allergy in children. 268 (posted May 26th, 2007)
Other possible sources of sensitization:
- How about peanut oil in vitamin A and D preparations?
According to a Feb 1999 Swedish study, sensitization to
peanut during childhood through consumption of vitamin A and D in
oil-based solution seems unlikely.78
(posted Aug. 6th, 1999)
- Another suggestion is that sensitization might occur by
contact with the skin, through the application of creams
containing arachis (peanut) oil for eczema, or nipple ointments in
mothers during breast feeding as reported by Lack G, Fox DES,
Golding J, at the AAAA&I Annual meeting in Washington, DC,
March 1998. (posted Aug 6th, 1999)
- Gideon Lack et al published an article in the New
England Journal of Medicine Mar 13th, 2003, entitiled
"Factors Associated with the Development of Peanut Allergy
in Childhood" where this factor is expanded on. In their
discussion, they state:
- "The absence of an association with maternal consumption
of peanuts during pregnancy, combined with our inability to
detect specific IgE to peanuts in cord blood, argues against
the occurence of sensitization in utero.
- Our data are not consistent with the hypothesis that
sensitization occurs by means of transmission of peanut
allergens in breast milk.
- Consumption of soy by the infants was
independently associated with peanut allergy and could not
be explained as a dietary response to other atopic
conditions. (see related article further down)
- We hypothesize that exposure to low doses of peanut
antigens through inflamed skin causes allergic
sensitization. The creams used were largely emollients for
the treatment of diaper rashes, eczema, dry skin, and
inflammatory cutaneous conditions in infancy. We conclude
that a family history of peanut allergy, the occurrence of
oozing, crusted skin rashes, topical use of peanut-oil-based
preparations, and exposure to soy protein may be causal
factors in the development of peanut allergy. "
171
(posted Mar 31st, 2003)
- Reactions to this publication appeared in the
July 17th, 2003 edition of the New Eng J
Medicine:
-
- 1. Ziegler JB: "...the patients with peanut
allergy and the controls were not matched...it is
possible that the patients with peanut allergy used
creams more often and used a larger number of
different creams...it is possible that the
children with peanut allergy had more severe and
troubling eczema...."
2. Roth JS: "...the authors do not specify the type
of peanut oil used in their clinical studies. In
England, the peanut oil is primarily crude oil that
contains peanut protein....which might explain the
reactions of the patients in this study.In the US
peanut oil...has no detectable peanut protein."
- 3. Matsui EC, and Wood RA: "We believe that the
choice of controls...may have exagerated the
association between exposure to soy protein and peanut
allergy...exposure to soy protein was
independently associated with peanut allergy. However,
children who have food allergies are more likely
than children who do not have such allergies to have
been given soy formula because of atopic
dermatitis. The authors' results may therefore
reflect a general association between food allergy and
exposure to soy protein, rather than a specific
association with peanut allergy....controls with food
allergy should be used in order to determine whether
there is a peanut-specific risk associated with
exposure to soy products."
4. Wilson, DHB, Wilson SM: "Vaginal suppositories,
which may be used in early pregnancy, have often
contained peanut oil. The effect of this maternal
variable may merit further investigation."
- 5. Wilkin JK, Pappas EG, DeCamp WH: "The FDA has
been aware of the concern about peanut oil and has
been evaluating options for reducing the risk.
There is an additional strategy that may lessen the
burden of peanut allergy: the removal of allergens
from peanut oil destined for use in therapeutic
products. Heating peanut oil at high
temperatures during refining may reduce the levels of
residual proteins sufficiently so that the oil
would not cause allergic reactions."
The authors reply:
- re 1: "Most preparations containing peanut oil
were used to treat diaper rash...the level of
exposure to preparations not containing peanut oil
was equivalent in all groups..."
re 2: "Even refined peanut oil heated at high
temperatures contains detectable protein, albeit
at reduced levels."
- re 3: "Dr Matsui and Wood sugest that the
association between the consumption of soy products
and peanut allergy may have been confounded by
atopy and other food allergies. Information on
soy consumption was obtained prospectively, as were
details of other food allergies."
re 4: "Maternal use of breast creams conaining
peanut oil, which was indirectly ingested by babies
who were breast-fed, was not associated with peanut
allergy. There was association only with oils that
were applied to the infant's skin."
- re 5: "....excessive heating may enhance the
allergenicity of the residual
protein."185
(posted Aug 1st, 2003)
-
- -Another reaction to the Lack New Eng J
Medicine article, comes from Peeters et al, in the
form of a Letter to the Editor that appeared in the
May 2004 J Allergy Clin Immunol: Peanut
allergy: Sensitization by peanut oil-containing local
therapeutics seems unlikely. The authors investigated
the allergeniciy of crude peanut oils, peanut oils at
different steps of the refining process, refined peanut
oils from supermarkets, pharmaceutical peanut oils, and a
number of current products containing peanut oil, like
vitamins. They concluded that it was unlikely that
significant amounts of protein remain in the oil phase
after the extraction, and they believe that their results
cast doubt on the proposition that pharmaceutical
products containing refined peanut oil play a role in
sensitization to peanut.227
(posted May 24th, 2004)
-
- -Re consumption of soy by infants mentioned in Gideon Lack's article above:
- In Pediatr Allergy Immunol. 2005 Dec;16(8):641-6. Klemola T et all have an article entitled Feeding a soy formula to children with cow's milk allergy: the development of immunoglobulin E-mediated allergy to soy and peanuts. 'We studied the development of immunoglobulin E antibodies specific to soy and peanuts and of allergic reactions caused by peanuts, in children with confirmed cow's milk (CM) allergy fed either a soy formula or an extensively hydrolyzed formula (EHF). Development of immunoglobulin E-associated allergy to soy and peanuts was rare in our study group of milk allergic children. The use of a soy formula during the first 2 yr of life did not increase the risk of development of peanut-specific immunoglobulin E antibodies or of clinical peanut allergy.
- Epicutaneous exposure to peanut protein prevents
oral tolerance and enhances allergic sensitization.is the
title of a publication that appeared in the June 2005
Clin Exp Allergy by Strid, Hourihane et al. The authors
found that in a mice model, primary skin exposure prevented the
subsequent induction of oral tolerance to peanut in an
antigen-specific manner. Upon oral challenge, mice became further
sensitized and developed strong peanut-specific IL-4 and IgE
responses. Furthermore, animals with existing tolerance to peanut
were partly sensitized following epicutaneous exposure.
- Conclusion: Epicutaneous exposure to peanut
protein can prevent induction of oral tolerance, and may
even modify existing tolerance to peanut. Epidermal exposure
to protein allergens selectively drives Th2-type responses,
and as such may promote sensitization to food proteins upon
gastrointestinal exposure.247
(posted June 29th, 2005)
-
-
-
-At the 2006 Annual Meeting of the AAAA&I in Miami,.FL,
Gideon Lack et al presented: Risk of peanut allergy associated
with high household exposure to peanut in infancy (J
Allergy Clin Immuno Vol 117, no 2, abstract # 140, p S35). The
authors state that 'over 90% of peanut allergic children react on
their first known oral exposure'. The route by which sensitisation
has occurred is unclear, Recent data suggest low-dose cutaneous
exposure as a likely route of sensitisation. They found, using
retrospective dietary questionnaires....including info about
peanut consumption amongst all other household
members....that exposure to environmental peanut during
infancy promotes sensitisation and that low levels may be
protective in atopic children. No special effect of maternal
consumption during pregnancy or lactation is observed. (posted
April 16th, 2006.)
-
- "Intrauterine
and early life dietary and environmental
determinants of allergy"
- This is the title of an excellent conference that was
presented by Dr Christine McCusker at the Seventh Bram Rose
Eastern Conference held in Hull June 6-8th, 2003. Here are
some of her findings regarding food allergy, and particularly
peanut allergy:
- re the immune system during pregnancy: it has been suggested
that maternal allergen exposure could induce active tolerance
in the fetus.
- re the immune system of the fetus: Fetus shows evidence of
low level specific immune responses to food and inhalant
antigens.
- High risk is usually defined as children with at least one
first degree relative with an atopic disease.
- Infant sensitization to hen's egg is predictive for later
sensitization to aero-allergens as well as eczema and food
allergies
- re maternal diet during pregnancy: isolated antenatal
studies not done in humans.
- Breast feeding is recommended but role in atopy and on
development of food allergies is controversial.
- In epidemiological studies, early life and long term
exposure to farms, stables and farm milk has a strong protective
effect against the development of allergies.
- Re impact of maternal / infant dietary avoidance of
allergenic foods:
- Studies have shown decreased incidence of infantile
eczema
- Studies demonstrate no effect on period prevalence of
food allergy by age 7 yrs
- No long-term positive impact has been defined
- Peanut ingestion in pregnancy was correlated with RAST
positivity in one study
- Evidence for peanut avoidance:
- Peanut protein has been detected in breast milk
- Allergic reactions have been documented with first known
exposure
- In one study, peanut-specific positive RAST tests were
found to correlate with more frequent maternal ingestion of
peanuts during pregnancy.
- In all studies of peanut avoidance during pregnancy and
lactation there were no significant differences in peanut and
non-peanut allergic children after 7 years of follow-up.
- It has been recently proposed that maternal stress may play
a role in development of atopic disease. References
(posted June 14th, 2003)
- -A very intersting item appeared in the
Montreal Gazette on Oct. 10, 2005 entitled Forget
cereal - feed baby enchiladas! written by J. M.
Hirsch, AP. Some highlights from the article:
- It turns out most advice parents get about weaning infant
onto solid foods - even from pediatricians - is more myth than
science...."There's a bunch of mythology out there about
this," said David Bergman, a Stanford University pediatrics
professor. "There's not much evidence to support any particular
way of doing things."..
- Yet experts say children over 6 months can handle most
anything, with a few caveats: Be cautious if you have a
family history of allergies; introduce one food at a time and
watch for any problems...
- Nancy Butte, a pediatrics professor at Baylor College of
Medicine, found that many strongly held assumptions - such as
the need to offer foods in a particular order or to delay
allergenic foods - have little scientific basis.
- David Ludwig of Children's Hospital Boston, a specialist in
pediatric nutrition, said some studies suggest rice and other
highly processed grain cereals actually could be among the worst
foods for infants."These foods ... digest very rapidly in the body
into sugar, raising blood sugar and insulin levels" and could
contribute to later health problems, including obesity, he
said.
- The lack of variety in the North American approach also
could be a problem. Food allergy fears get some of the
blame for the bland approach. For decades, doctors have said the
best way to prevent allergies is to limit infants to bland foods,
avoiding seasonings, citrus, nuts and certain seafood.But
Butte's review found no evidence that children without family
histories of food allergies benefit from this. Others
suspect avoiding certain foods or eating bland diets actually
could make allergies more likely. (posted Oct. 13th,
2005)
- -A very interesting article appeared on the front page of the
March 20th, 2006 'USA Today' giving more insight into the
'hygiene theory' alluded to a couple times elsewhere in this
review: To
head off allergies, expose your kids to pets and dirt early.
Really.
- (pdf version of
article) See the pdf article"Asthmatic
kids under a cloud." (posted March 20th, 2006)
-
-
- Diagnosis of
food allergies
-The double-blind, placebo-controlled food challenge
(DBPCFC) is the 'gold standard' for diagnosis of food
hypersensitivity. Skin prick tests and RASTs [allergy tests
done on blood sample of patient] are sensitive indicators of
food-specific IgE antibodies but poor predictors of clinical
reactivity. In other words, challenges are the only sure way of
appropriately diagnosing food allergies, especially in cases of
suspected food allergy 8.
-the evaluation of adverse reactions to foods depends on a
careful clinical history, diagnostic studies including appropriate
skin testing or in vitro testing with food extracts
(1997). . . 11
Comment:
Dr. Rhoda Sheryl Kagan: Stating that positive skin
prick tests are "poor predictors of clinical reactivity" in the
words of the authors, one should not forget that negative tests
may also be poor predictors of sensitivity. (Oct. 1998)
-The skin prick test is the most widely used test for detecting
food hypersensitivity. . . using fresh foods may be more
effective for detecting the sensitivity to food allergens. Fresh
foods should be used for primary testing for egg, peanut, and cow's
milk sensitivity, according to some authors 9,28.
Comment:
Dr. H. Blumer: (and I agree, based on personal
experience) Allergy to eggs, cow's milk and peanut, will be
detected by available allergy extracts, and fresh foods are not
usually necessary. In cases of suspected allergy to these foods,
fresh foods could be used if the tests are negative using the
regular extracts. (Oct. 1998)
- -Food extracts for diagnostic purposes
often lack sufficient activity and consistency...divergent
allergenic activities are found at times...heating of some foods
remarkably reduce the activity...variations in extracting
conditions...and storage stability..41.
-
- -Eigenmann and Sampson evaluated a more
sophisticated method of interpreting skin tests while the results
of double-blind, placebo-controlled challenges were considered the
'gold-standard' for diagnosis, and found that skin prick tests
are a useful procedure for evaluating clinical reactivity to egg,
milk, peanut and wheat....and the usual grading method of a
positive skin test recorded as a wheal diameter 3 mm greater than
the negative control remains just as good a predictive value
43.
(posted Feb 2, 1999)
-
- -Armstrong and Rylance, in the Feb.
1999 Archives of Diseases of Children, report their
findings in their study entitled "Defininte diagnosis of nut
allergy." Out of 96 children referred over a 27 month period
(1994-1996) for nut allergies presenting with urticaria, facial
swelling, anaphylactic shock, vomiting... 16 children from a
sample of 51 who were tested for nut allergy had no reaction to an
oral challenge. Positive IgE against peanuts was found in 9 of
these 16 children. Their conclusions were: skin prick testing
and IgE measured by RAST tests are inadequate tests for nut
allergy. ---the definitive diagnosis test for nut allergy in the
hospital setting is direct oral challenge 69
(posted May 25th, 1999)
-
-
- -Bock, at Allergy Update 1999 in Toronto,
stressed that skin tests detect specific antibody.
Hypersensitiviy is demonstrated by double-blind placebo-controlled
food challenges. Unfortunately, reliance on positive food skin
tests is much lower than on the negative skin tests in regard to
predictive accuracy or value. (posted July 11th, 1999)
-
-Regarding "a careful clinical history", two
observations:
-refusal or dislike of a food right from its first
introduction in the child's diet could be a sign of allergy to
that particular food.
-the food that may contain the allergen, either hidden
or non-identified, is usually immediately spat out or vomitted
if any amount was swallowed, as if by a "defense mechanism"
in the allergic child. Nevertheless, in the severely
allergic child, even if the food was not swallowed, a certain
degree of absorption has taken place, and a reaction may occur
(not in all cases): vomiting, angioedema (swelling of throat,
tongue, or lips), itchiness, or hives, fortunately of short
duration because of this characteristic.
- -We occasionally see children in our practice that have
always disliked and refused peanut butter or foods containing
peanut, but had never had any allergic reaction; skin
tests, however, to peanut are sometimes very positive.
(personal comment, posted Jan 13th, 2000)
-
-
-
-
Predictive value of skin
tests (to peanuts or other foods):
-
- in children who have never previously eaten
peanuts:
-Skin-prick testing and peanut-specific IgE (immunoglobulin
E) antibody levels done by the RAST [radio-allergo-sorbent
test] blood test) do not predict clinical severity
(1997) 2.
(skin tests and blood tests identifying peanut-specific antibody
are not good predictors of the intensity of the allergy)
-Zimmerman and coll. reported in 1989 a positive RAST
test to peanut in 64 % of children who gave no history of
having eaten peanuts 37.
-At the annual meeting of the AAAA&I held Mar 3-8th,
2000 in San Diego, Hayami and Kagan presented a retrospective
study to assess the use of prick skin tests (PST) as a
diagnostic tool for peanut allergy in children who have never
knowingly ingested peanuts, also specificity, sensitivity, and
positive and negative predictive values of PSTs to peanuts in
children who have undergone a blinded, placebo controlled
challenge. PSTs were considered positive if the wheal was 3mm >
negative control. All subjects had a positive skin test to peanut
despite no prior history of peanut ingestion, and all have
practiced strict avoidance of peanuts. The testing was done
because of family history of peanut allergy, parental request,
atopic dermatitis, or as part of other allergy tests. Food
challenges were offered to patients to determine if the PST was
indicative of true allergy. The mean age of children undergoing
food challenge was 5.5 yrs. Of the 20 subjects, 6 had positive
challenges. The mean wheal diameter of children with negative
challenges was 7.57 mm (range 3-15mm). The mean wheal diameter of
children with positive challenges was 10.66 mm (range 7-14mm).
The positive predictive value of a peanut skin test > 3mm was
33.3%. The positive predictive value increased to 46.1% when only
skin tests > 6mm were considered. All of the subjects with
a positive challenge had wheals > 6mm. There was a trend to
larger mean wheal diameters in children with positive challenges.
No correlation was found between the presence of asthma, atopic
dermatitis, or other food allergy. The poor predictive value of
the PST in children without a clinical history of peanut allergy
reaffirms the need to conduct oral challenges prior to the
designation of peanut allergy. There is a suggestion that PST
< 6mm may predict negative challenges.(posted Mar 9th,
2000)
-"Interstingly, the detection of food-specific IgE antibody
is not sufficient to diagnose clinical reactivity to a food; that is,
an individual may have no clinical reaction upon ingestion of a
food to which there is a positive allergy skin test or
radioallergosorbent test (RAST)." 101
(posted Dec 10th, 2000)
- - In the Jan 2001 Clin Exp Allergy, Pucar,
Kagan, Lim and Clarke authored Peanut challenge: a
retrospective study of 140 patients. The authors state that
accurate diagnosis of peanut allergy is essential given
that it is a lifelong and possibly fatal food allergy, and that
diagnosis relies on patient history, prick skin test (PST), and
in many situations, food challenge. The aims of their study
were: a) to assess the safety of food challenges, b) to
estimate the sensitiviy, specificity, and the positive and
negative predictive values of PST to peanut performed in those
who underwent a peanut challenge. On the 140 peanut challenges
performed on 140 patients:
- 18 were positve (urticaria, oro-pharyngeal irritation,
rhinitis, vomiting and abdominal pain.)
- 10 required treatment (antihistmine, +/- epinephrine, +/-
salbutamol)
- sensitivity of PST: 100%
- specificity of PST: 62.3%
- positive predictive value of PST: 28.1%
- negative predictive value of PST:100%
- Conclusion of the authors:
- Given the poor positive predictive value and the specifity
of the PST, a peanut challenge is usually required to diagnose
peanut allergy with certainty when the PST is positive. When the
history is strongly suggestive and the PST is borderline positive,
i.e. 3 or 4 mm, peanut challenge is generally necessary to confirm
the diagnosis.
-
- Given the excellent negative predictive value and
sensitivity of PST, a blinded peanut challenge is unnecessary
in the context of a negative PST except for patients with a
history strongly suggestive of immediate hypersensitivity.
These patients should be individually assessed for the need to
undergo a blinded challenge.111
(posted Feb. 13th, 2001)
-
- A further study by Kagan R et al, published in the Ann
Allergy Asthma Immunol. in June 2003, entitled "The
predictive value of a positive prick skin test to peanut in
atopic, peanut-naive children". 47 children, between 1994
and 2001 were identified who had a positive peanut prick skin
test (PST), no previous peanut ingestion, and had
undergone a peanut challenge.
Results:
- 49% of the challenges were positive.
- at a PST cutoff of > or = 5mm, the sensitivity and
positive predictive value was 100% whereas
- the specificity and positive predictive value was
between 12.5% and 52.3% in children with a PST less than
5mm.
- there was a trend to increased atopic features in the
positive challenge group
- those with a negative challenge had a lower PST wheal
diameter.
- the mean range peanut-specific IgE value of nine
subjects in the negative challenge group was 0.63kU/L compared
with 13.1kU/L for the five subjects in the positive challenge
group.
- Conclusions of the authors: We show that 49% of atopic,
peanut-naive children sensitized to peanut developed allergic
symptoms during oral provocation with peanut. Although the
sensitivity of the PST at > or = 5mm for the detection of
peanut allergy in this study was 100%, our small sample size
limits the applicability of this value. Further investigation is
needed to determine whether children with wheal diameters of 3 or
4 mm, perhaps coupled with low peanut-specific IgE, could undergo
less resource-intensive, accelerated challenges. .186
(posted Aug 4th, 2003)
- Personal comment: It is a known fact that if skin
prick tests are done in the general population at random,
approx. 40% will show positive skin tests, half of them not
clinically significant seeing that approx. 20% of people are
allergic. Secondly, the size of the SPT is to be taken into
consideration, along with a peanut-specific IgE which would
predictably be elevated.
- Question: Because more than 70% of initial
allergic reactions to peanut in children occur following
first contact with the food, should all allergic (atopic)
children be tested to peanuts if this food is not yet part
of their diet, either because of a family history of peanut
allergy, or being allergic and considered at risk, the
introduction of highly allergenic foods such as peanut was
recommended only at a age 4 or 5? Close to 50% of initial
allergic reactions to peanut could be prevented! (posted
Aug 4th, 2003)
The authors state in the discussion of the paper,
"Because a PST is generally used to confirm suspected food
allergy following symptoms consistent with an IgE-mediated
allergic reaction, and because sensitization in the absence of
clinical symptoms is not clinically relevant, performing a PST
before known ingeston of a food is not generally recommended.
However, peanut allergy appears to differ, as most allergic
children react on their first known ingestion. Additionally,
because peanut allergy has been associated with a sgnificant
risk of anaphylaxis, identifying the "at-risk" children would
be useful before the first "field" reaction."105
..."Furthermore, although the majority of children
under the age of 5 years react to their first exposure to
peanut, some children may only develop peanut allergy upon
subsequent exposure. It is possible, therefore, that
sensitization occurred during the challenge, suggesting a
negative challenge may not preclude peanut allergy with
certainty. Incomplete data are available on the follow-up of
these patients, and many families have chosen to introduce only
precautionary-labeled peanut products, while continuing to
avoid overtly peanut-containg foods." (posted Aug 22nd,
2003)
-
-
- -In the March 2001 J Allergy and Clnin Immunol,
Drs Zimmerman and Urch wrote a letter to the editor entitled
Peanut Allergy: Children who lose the positive skin test
response in which they report on a study undertaken on 96
children who had shown a positive skin test to peanut, regardless
of whether they had had a clinical reaction to peanut, who were
seen one year later and characterized. Of the 96 patients, 66 had
a history of clinical reaction to peanut, including one or more of
hives, erythema, angioedema, vomiting, and respiratory symptoms;
the rest were found to have positive skin test reactions without
ever knowingly having had peanut. At visit 2, 10 patients had lost
the positive skin test response (8 of whom had a prior history of
clinical reaction to peanut), had negative responses to RAST
testing, had fewer positive tests to other allergens, and
successfully underwent oral challenge without reacting. The
data confirm that some children lose the positive skin test
response to peanut and are less atopic than those who retain the
positive response. Although they represent only 10% of the
patients who had positive peanut skin results at visit one, it is
important to identify them and perform the oral challenge because
peanut can be re-introduced into their diet.114
(posted April 14th, 2001)
-In the Jan 2001 Curr Allergy Rep, (posted in
Medline only in April, 2002 for some reason)Williams has an article
entitled Skin testing and food challenges for the evaluation of
food allergy in which he states "skin prick tests for the
common food allergens are excellent tools for identifying those at
very low risk of reaction on eating the food, but are of
variable value in identifying patients who will be positive on
challenge...Skin tests to less common food allergens,
especially fruits, are less well characterized and may require
use of the food item itself as the source of allergen rather
than a commercially prepared extract. For a few foods, the CAP
system fluorescent enzyme immunoassay (Pharmacia, Peapack, NJ)
recently has been shown to have good ability to identify patients at
very high probability of reaction on oral challenge." see
Sampson's reference, below. (posted April 29th, 2002)152
See also predictive value of RAST tests (IgE
titers) below.
- -Rance, Abbal and Lauwers-Cances published Improved
screening for peanut allergy by the combined use of skin prick
tests and specific IgE assays, in the June 2002 J
Allergy Clin Immunol. The aim of the study was to develop a
new strategy for diagnosing peanut allergy while reducing the need
for DBPCFCs (double-blind, placebo-controlled food challenges).
They studied 363 children referred for evaluation of suspected
food hypersensitivity. Performance characteristics of skin tests
(using commercial and fresh food preparations) and of the IgE
assay were assessed compared with the challenges.
- Results:-according to the challenges: 177 children were
allergic to peanut, and 186 were not.
- -the performance characteristics of the skin tests
were superior using raw extracts because the negative
predictive value was 100% (if the wheal diamater was less
than 3mm, they could be quite certain the child was not
allergic). On the other hand, if the wheal diamater was
larger than 3mm, the predicive value was only 74%. If the
skin test wheal was 16mm or larger in diameter, the
predictive value was 100% that the child was allergic.
-specific IgE concentrations of 57 kU(A)L or greater were
associated with a positive predictive value of 100%.
- Conclusion: Peanut DBPCFCs can be avoided when skin tests
done with raw extracts resulted in wheals of 3mm or less and a
specific IgE concentration of less than 57 kU(A)L and also when
wheal diameters were 16mm or more or specific IgE values 57 kU or
greater. Otherwise DBPCFCs were indispensable for the unequivocal
diagnosis of peanut allergy. 159
(posted July 6th, 2002)
-
-Hill DJ, Heine RG, Hosking CS in the Oct 2004 Pediatr
Allergy Immunol. published The diagnostic value of skin prick
testing in children with food allergy. The authors state,
"we developed diagnostic cut-off levels for SPT (skin prick
tests) in children with allergy to cow milk, egg and
peanut. Based on 555 open food challenges in 467 children
(median age 3.0 yrs) we defined food-specific SPT wheal diameters
that were '100% diagnostic' for allergy to cow's milk (>/=8
mm), egg (>/=7 mm) and peanut (>/=8 mm). In children
<2 yr of age, the corresponding wheal diameters were >/=6 mm,
>/=5 mm and >/=4 mm, respectively. These SPT cut-off levels
were prospectively validated in 90 consecutive children </=2
yrs with challenge-proven food allergy. In young infants under 6
months of age who have not previously been exposed to a particular
food item, the SPT were often negative or below the diagnostic
cut-off but reached the diagnostic cut-off at the time of challenge
in the second year of life....When applying published 95%-positive
predictive CAP values, the diagnostic accuracy of SPT and IgE
antibody levels was similar for cow's milk, but SPT was more
sensitive in diagnosing allergy to egg (p < 0.0001) and
peanut (p < 0.0001)."235
(posted Oct. 18th, 2004)
-
-
-Dr Jay M. Portnoy, co-chairman of a panel on 'practice
parameters of food allergies', published in the March 2006
Annals of Allergy, Asthma and Immunology said to WebMD,
'I see patients all the time who go to a doctor, skin-test
positive to lots of different foods, and are advised to avoid all
of these foods. It makes their life miserable. And it turns out
that they're not truly allergic to all these foods after all."
See pdf
version of the WebMd
article. See also Food
Allergy Guidelines in the section 'Dealing with peanut
allergy, (posted March 31st, 2006)
-In Pediatr Allergy Immunol. 2007 May;18(3):224-3, Nolan et al published 'Skin prick testing predicts peanut challenge outcome in previously allergic or sensitized children with low serum peanut-specific IgE antibody concentration'. Children allergic to peanut and having a serum IgE titer of <10 k UA/L and had a positive skin test = or > 7mm had a 97% chance of having a positive challenge. (posted May 26th, 2007) 270
-
-
- Recent
studies on the predictive value of IgE
titers
-
- -In the May, 2001 J Allergy Clin Immunol,
Dr Hugh Sampson, published a study entitled Utility of
food-specific IgE concentrations in predicting symptomatic food
allergy. Using the Pharmacia CAP System FEIA to
quantify food-specific IgE antibody concentrations of the sera of
100 consecutive children and adolescents referred for evaluation
of food allergy, he found the test useful for diagnosing
symptomatic allergy to egg, milk, peanut and fish, and could
eliminate the need to perform double-blind, placebo-controlled
food challenges in a significant number of children.121
(posted June 12th, 2001)
-
- -Somewhat similar to the above article, Hill et al report in
the Nov 2000 Clin Exp Allergy 31(7); 1031-1035 on
their experience comparing their "100% diagnostic skin positive
test levels", (where an 8mm diametre skin test reaction or more
was 100% predictive of a positive food challenge)124
to two IgE blood determinations (EAST or enzyme allergo-sorbent
test, and CAP test). In their findings, they found that the
predictability of their "100% diagnostic skin positive test
levels" was superior to the IgE tests.125
(posted July 13th, 2001)
-
- -Van Odijk and collaborators in their article
entitled"Specific IgE antibodies to peanut in western Sweden-
has the occurrence of peanut allergy increased without an increase
in consumption?" that appeared in the June 2001
Allergy, found the following when they looked at all
IgE specific tests for peanut during a 5-year period (2417 tests)
and the connection with age, sex, symptoms and other atopic
manifestations:
- there was an increased prevalence of detectable IgE
antibodies
- more than 80 individuals under 2 years of age were
sensitized to peanut
- individuals with detectable IgE antibodies reported a
shorter reaction time after eating peanuts than indiviudals
with normal IgE antibody levels
- patients with normal or low IgE antibody levels were not
always free of symptoms even though their risk of allergic
symptoms was reduced.127
(posted July 31st, 2001)
- -See also :
-
-
- Immuno
CAP test specific IgE blood test.
-
- UniCap
InvitroSight version 3.1 (posted Oct 6th, 2003)
-
-
-
- -In the Oct 2002 Current Paediatrics, A. Ives
and J. O'B. Hourihane have an excellent article entitiled
Evidence-based diagnosis of food allergy. The summary reads
as follows:
- "There is an increasing body of robust, evidence-based
practice allowing refinement of current diagnostic approaches
outside the setting of research-oriented practice. The diagnosis
of IgE-associated food allergy is a synthesis of history,
examination, serum-specific IgE, skin tests
and food challenge/elimination diets. Food
challenges remain the gold standard for diagnosis, but these
can be avoided in those with a good histroy and positive skin
tests or positive specific IgE, especially if these levels are
above the 95% positive predictive value (PPV). Negative tests are
very important in ruling out possible triggers, due to the
excellent negative predictive value (NPV) of both specific IgE and
skin-prick tests."
- -The history is an essential part of any
diagnosis....is the problem allergic or one of the many
possible differential diagnoses? Sometimes multiple foods
are implicated, but it is very unusual for anyone to have
IgE-associated reactions to more than three foods. The
history can be notoriously inaccurate, care should be taken
in its interpretation....False association between food
allergy and chronic problems, e.g. chronic fatigue syndrome,
or rhumatoid arthritis, in which no good evidence exists to
support their association with food allergy.
-Particular attention in the examination needs to be
paid to the skin, respiratory tract and gastro-intestinal
tract (rashes, ENT problems, and chest
abnormalities)...atopic dermatitis, asthma and
rhino-conjunctivitis need to be looked for...Examination is
crucial before a food challenge as subtle changes of
appearance...may be important early signs of reactivity after
allergen exposure.
- -Skin prick testing is one of the main investigations
used in allergy diagnosis.... it is the in-vivo
counterpart of serum-specific IgE... measuring the presence
of allergen-specific IgE in the skin....very safe. Is is
also important to note that the degree of skin reactivity
does not correlate with the severity of the clinical
reaction on ingestion of the food. It has a
negative predictive accuracy of approaching 100%,
meaning that if the skin prick test is negative then
it is very unlikely that the patient will react if the food
in question is ingested. A food challenge is therefore not
always required as it is likely to be negative.
Unfortunately, the positive predictive accuracy of the test
is only in the range of 50-60%, meaning that a positive
reaction will only predict a positive food challenge in
50-60% of patients. The remainder are sensitized but do not
react clinically and can therefore usually tolerate the food
in question. High-quality extracts should be used, a
good test technique and accurate measurement of the results.
In some cases, tests should be done with fresh foods.
- -Serum-specific IgE levels, like skin tests,
have a similar predictive value- a negative specific
IgE has an excellent negative predictive value for excluding
IgE-mediated food reactions, but a positive specific IgE
does not imply that clinical reactivity will occur.
Studies have shown that it is possible to quantify levels of
specific IgE above which the positive predictive value is
over 95% as long as results are expressed as absolute levels
of IgE, not RAST scores (see references above).
-Food challenges are performed to clarify which
substances are causing an allergic reaction, to identify which
foods may no longer cause a reaction, to assess non
IgE-mediated reactions, to refute a history of supposed
allergy, to assess cases where the skin tests or IgE are
positive but there is no history of ingestion, or a poor
history, and to assess reactions to other components of the
diet, e.g. additives, colorings, etc.
- -Elimination diets can be performed with the help
of a dietician...they help diagnosis also in non IgE
mediated reactions...should be followed by a food
challenge.
-Beware of controversial diagnostic procedures,
unproven, that are being made available to the general
public, such as applied kinesiology, cytotoxic testing, tests
involving other immunoglobulins, electrodermal (Vega) testing,
etc166.
(posted Dec 13th, 2002)
-
- -In the April 2003 Allerg Immunol (Paris)
Moneret-Vautrin, Kanny and Fremont have an aricle entitled
Laboratory tests for diagnosis of food allergy: advantages,
disadvantages and future perspectives. ..."Prick tests are
closer to clinical symptoms than biological tests. However,
the diagnosis of food allergy is based on standardized oral
challenges. Exceptions are high levels of specific IgEs to egg
(> 6kUl/l), peanut (>15kUl/l), fish (>20 kUl/l) and milk
(>32kUl/l), reaching a 95% predictive positive
value...Research developments will have impact on the
development of new diagnostic tools: allergen mixes
reinforcing a food extract by associated recombinant major
allergens, multiple combination of recombinant allergens (chips)
or tests with synthetic epitopes aimed at the prediction of
recovery. 176
(posted June 25th, 2003)
-
-
- -In a similar study by Clark AT and Ewan PW.
Interpretation of tests for nut allergy in one thousand
patients, in relation to allergy or tolerance, published in
the Aug 2003 Clin Exp Allergy. The authors
state in their abstract: "In the US, 7.8% are sensitized (have
nut-specific IgE), but not all those sensitized are allergic.
"(NB. In the UK, nuts include peanuts) "Lack of data makes
interpretation of tests for nut-specific IgE difficult. This
is the first study to investigate the clinical significance of
test results for peanut and tree nut allergy in allergic or
tolerant patients. Findings are related to the severity of the
allergy. An observational study of 1000 children and adults
allergic to at least one nut was done. History of reactions
(severity graded) or tolerance to up to five nuts was obtained and
skin prick test (SPT) and seum-specific IgE (CAP) performed.
- RESULTS:
- There was no correlation between SPT size and graded
severity of worst reaction for all nuts combined or for peanut,
hazelnut, almond and walnut.
- For CAP, there was no correlation for all nuts.
- Where patients tolerated a nut, 43% had a positive SPT
of 3-7mm and 3% >/= 8mm. For CAP, 35% were positive
(0.35-14.99kU/L) and 5% >/=15 kU/l.
- In SPT range 3-7mm, 54% were allergic and 46% were
tolerant.
- There was poor concordance between SPT and CAP (66%).
- Of patients with a clear nut-allergic history, only 0.5%
had negative SPT, but 22% negative CAP.
- CONCLUSIONS:
- Magnitude of SPT or CAP does not predict clinical
severity, with no difference between minor urticaria and
anaphylaxis.
- SPT is more reliable than CAP in confirming
allergy.
- 46% of those tolerant to a nut have positive tests
>/= 3mm (sensitized but not allergic)
- One cannot predict clinical reactivity from results in a
wide 'grey area' of SPT 3-7mm; 22% of negative CAPs are falsely
reassuring and 40% of positive CAPs are misleading. This
emphasizes the importance of history. Understanding this is
essential for accurate diagnosis.
- Patients with SPT >/= 8mm and CAP >/= 15 kU/L were
rarely tolerant so these levels are almost always (in >/=
95%) diagnostic. 192
(posted Aug 18th, 2003)
-
- In the July 2004 J Allergy Clin Immunol , Perry
et al published a study entitled The relationship of
allergen-specific IgE levels and oral food challenge outcome.
For the 173 peanut challenges, 59% passed, and the medians for
those who passed or failed were 0.5 kUA/L and 1.9 kUA/L,
respectively (P < .001).
- -For patients with a clear history of a peanut reaction , the
trend for increasing failure rate with increasing peanut-specific
IgE level was statistically significant (P < .01), with 76% of
patients passing the challenge with an IgE level of less than 0.35
kUA/L, 44% passing with a level between 0.36 and 2 kUA/L, 40%
passing with a level between 2 and 4.9 kUA/L, and none passing
with a level greater than 5 kUA/L.
- -For those patients without a clear reaction history, 88%
of patients passed with a negative peanut-specific IgE level of
less than 0.35 kUA/L, 71% passed with a level of 0.36 to 2
kUA/L, 33% passed with a level of 2 to 4.9 kUA/L, and 77%
passed with a level greater than 5 kUA/L.
- Conclusions: For peanut, we recommend that patients with
a clear history of reaction be challenged when the IgE level is
less than 2 kUA/L, whereas a cutoff level of 5 kUA/L is
recommended for those without a clear history of reaction.
Cutoff levels for these 2 reaction groups most likely differ
because many patients who were avoiding peanut solely on the
basis of a positive test result might never have truly had
peanut allergy. Allergen-specific IgE concentrations to peanut
serve as useful predictors of challenge outcome and should be
considered when selecting patients for oral challenge to these
foods.228
(posted July 12th, 2004)
-
-
- -L'allergie à l'arachide: une observation
exemplaire202
(Allergy to peanuts: a perfect example) is the title of an
article published in Revue Française d'Allergologie et
d'Immunologie Clinique vol 43, numéro 8, 2003 by
Scaramuzza et coll. According to the authors, "it enderlines the
need to analyse the characteristics of this food allergy:
- the increase of sensitization which appears at a younger age
and often occult.
- the risk factors (including genetic predisposition)
- the risk of cross reactions with other legumes or with
nuts
- the severity of clinical manifestations, which could be
biphasic.
- diagnostic features and management".
- They report the case of Eric, aged 7 years, who
underwent an oral challenge with peanut. He had never
eaten peanuts, having avoided nuts and peanuts because of
his homozygous twin having presented angioedema caused by
cashew nut at age three...The family history is positive
and Eric himself had atopic dermatitis till age 18 months,
and now has asthma since age three, controlled...Skin
prick allergy tests were positive to house dust mites,
cockroaches, but also to peanut (4mm) and to mixed nuts
(2mm)..Peanut-specific IgE was: 1.81 kU/l, cashew:
1.54 kU/l, and 0.44 for hazelnut.
- The oral challenge was open with increasing doses of peanut
every 20 minutes. It was positive at the cumulative dose of 777
mg. Fifteen minutes following the provoking dose (1/2 a
peanut) Eric became lethargic, had a fall in blood pressure,
abdominal pain and generalized urticaria. He was treated with an
injection of epinephrine, loratadine, and betamethasone orally. A
second injection of epinephrine was administered one hour later
because of recurrence of anaphylaxis, along with salbutamol for
associated asthma. Eric was discharged five hours later with
Anapen (epinephrine kit for self administration) and told to avoid
nuts, peanuts and peanut oil.
- Discussion:
- -The prevalence of peanut allergy in France is 1%128
- -It is the 2nd cause of food allergy in children under 3
years of age after egg, and the first cause after age
three.
-Food allergy seems to be a condition occurring in
developped countries, a notion attributed to the hygiene
hypothesis and to different ways of processing peanuts, roasted
or raw peanuts being more allergenic than fried or boiled.
120
- -Sensitization at an earlier age to peanut has become more
and more frequent in the last ten years..33,
13,
163
Incriminating factors being: peanut has become a staple food in
a big way everywhere, in particular by pregnant and
breast-feeding women,2,
115
and its introduction at a much earlier age in the diet of
children, also use of body creams containing peanut oil or
almond oil, and of topical medications containing peanut
oil..33
Other risk factors: atopic personal and family history-
siblings have a 7% chance of becoming allergic to
peanut. The risk increases in homozygous twins up to
64%.
-Authors' conclusion: The diagnosis of peanut allergy is
based on the history, allergy skin tests, specific IgE titres.
It must be concluded with an oral challenge under strict
hospital supervision in a patient having never reacted to or eaten
peanut, with a positive skin test and peanut-specific IgE less
than 14kU/l, as in the case of our young patient. A positive skin
test (which has an excellent negative predictive value) could only
indicate sensitization. An IgE titre of more than 14 kU/l has a
predictive positive value of 95%, but if the IgE titre is less
than 0.35kU/l its predicitve negative value is NOT
100%.121
(posted Dec 15th, 2003)
-
- -Dr Ham Pong presented his clinical research findings on
Peanut allergy at the XI International Food Allergy
Symposium held at the American College of Allergy, Asthma &
Immunology meeting in New Orleans in 2003. The research is
summarized in the Allergy and Asthma News, issue 2, 2004 of the
Allergy/Asthma Information Association:
- -'Research has found that peanut allergy can resolve in up
to 20% of children.
- -Knowing which children will outgrow their peanut allergy
and who should be given a peanut challenge is a constant trial
for allergists...'
- -Dr Pong chose to do a study to attempt to further
delineate which children can be safely challenged.
- -60 children , aged 4 to 13, were chosen on the
following criteria:
- -the peanut-specific IgE (p-IgE) was less or equal to
5ku/L
- -history of immediate IgE type allergic reaction and
a positive prick skin test (PST) to peanut OR a positive
PST but the child had never ingested peanut
- -the child has had no allergic reaction in the past
two years.
- -The majority of the challenges started as a single
blind challenge for the first four doses and proceeded to
open challenges when the dose of peanut equalled or exceeded
one peanut.
- -A negative challenge was indicated by tolerance of a
cumulative dose of 21-28 peanuts over a three hour period, with
a single final dose of 12 peanuts.
- -A challenge was considered positive if there were
objective signs suggestive of an IgE-mediated allergy e.g.
urticaria (hives), angioedema (swelling), bronchospasm
(wheezing), immediate vomiting, etc. Positive oral
challenges occurred in 17 of the 60 children, or 28% of the
cases. There was one equivocal challenge from the
group.
- -Negative oral challenges occurred in 42 of the 60
children, or 70% of the cases. In this group, 31 or 74% had
a positive SPT. As a group, these children had lower
SPTs and p-IgE than the positive challenges. On an
individual basis, PSTs and/or p-IgE did not separate
those with negative or positive challenges, or anaphylaxis
except for a negative SPT that always resulted in
a negative challenge.
- -Of the 60 children, 28 had negative p-IgE. Six of these
28 had positive challenges. Therefore a negative p-IgE
still resulted in a positive challenge in 21% of the children.
While a negative p-IgE often implies that the peanut allergy
may be gone, it is not always so.
-Of the 6 children with a negative p-IgE who had reactions
on challenge, 3 resulted in mild anaphylaxis, easily reversed
with treatment.
- Final result of the study found that Unicap testing
predicted a larger number of peanut allergy resolvers than
prick skin testing. In general, PST size and p-IgE were
lower in the negative challenge versus the positive
challenge groups. However, on an individual basis, neither
were predictive of negative challenges, or anaphylactic
response during a positive challenge. The only exception was
a negative PST which predicted a negative challenge,
irrespective of the p-IgE....This study clearly confirms
that 70% of children who have not had a reaction for over
two years and who also meet the criteria for lowered p-IgE
and based on prick skin testing may have outgrown their
peanut allegy....follow-up of these apparent peanut
resolvers is important to ensure they have truly outgrown
their allergy. (posted July 26th, 2004)
-
-
-
-
- -At the AAAA&I Annual Meeting in San Antonio, March
18-22, 2005, Te Pas, et al presented Predicting the
resolution of peanut allergy in children using skin prick testing
and RAST: A systematic review. Of the 567 articles
reviewed....a negative skin prick test was slightly better than
a negative RAST at predicting which children have outgrown their
peanut allergy. However, they concluded, using these cutoffs,
one misses approx. 40% of kids who have a positive test but would
pass a peanut challenge. (posted April 22nd, 2005)
- -At the same meeting (San Antonio, Texas, 2005),
Borici-Mazi et al. presented Monitoring of peanut allergic
patients with serum-specific. IgE. They looked at the optimum
frequency of measuring the levels of the peanut-specific IgE.
Based on their results looking at 118 patients, from 1997 till
present, they concluded that "it is probably adequate to measure
the levels every 3 to 5 years as part of screening for developing
of tolerance to ingested peanut and predict the results of future
peanut challenges." (posted April 24th, 2005)
- - In the June, 2005 J Allergy Clin Immunol,
Roberts G and Lack G published Diagnosing peanut allergy
with skin prick and specific IgE testing. Objective: To
determine the predictive value of a wheal >/= 8 mm or serum
specific IgE >/= 15 kU A /L for clinical allergy and
investigate whether results are generalizeable. Results: a skin
prick result >/= 8 mm or a specific IgE >/= 15 kU A /L have
a high predictive value for clinical allergy to peanut and that
these cutoff figures appear generalizeable to different
populations of children undergoing an assessment for peanut
allergy.246
(posted June 12th, 2005)
- In the July 2003 J Allergy Clin
Immunol, Beyer et al had a publication (which should have been
posted much earlier) entitled Measurement of peptide-specific
IgE as an additional tool in identifying patients with clinical
reactivity to peanuts. As the authors note in the abstract of
the article,"Diagnostic decision levels of food-specific IgE
antibody concentrations have been described" (as seen in the above
postings). "However, many patients still need to undergo oral
peanut challenges because their IgE levels are in the
nondiagnostic level".The aim of their study was to determine
whether differences exist in IgE-binding epitope recognition
between sensitized children with and without symptomatic peanut
allergy. Eight peptides representing the immunodominant sequential
epitopes on Ara h 1, 2, and 3 were synthesized ... Individual
patient labeling was performed with sera from 15 patients with
symptomatic peanut allergy and 16 patients who were sensitized but
tolerant. Ten of these 16 patients had "outgrown" their allergy.
- RESULTS:
- Regardless of their peanut-specific IgE levels, most
patients with symptomatic peanut allergy showed IgE binding to the
3 immunodominant epitopes on Ara h 2.
- In contrast, each of these epitopes was recognized by <
10% of the tolerant patients.
- In addition, tolerant patients did not recognize 2
immunodominant epitopes on Ara h 1.
- At least 93% of symptomatic, but only 12.5% of tolerant
patients, recognized 1 of these "predictive" epitopes on Ara h 1
or 2.
- Moreover, the cumulative IgE binding to the peanut peptides
was significantly higher in patients with peanut allergy than in
tolerant patients.
- With up to 50% of patients with peanut-specific IgE levels
below diagnostic decision levels still being clinically reactive,
oral food challenges could be avoided in ~90% of these patients
through determination of peptide-specific IgE.
- CONCLUSIONS: Determination of epitope recognition provides
an additional tool to diagnose symptomatic peanut allergy,
especially in children with peanut-specific IgE below diagnostic
decision levels. (posted only March 14th, 2004)214
-
- -In the Oct. 2004 Pediatr Allergy Immunol. Odijk
J. et al have an article entitled Specific immunoglobulin E
antibodies to peanut over time in relation to peanut intake,
symptoms and age. The authors found that..."Increased IgE
antibody levels during follow-up was related to age...Exposure to
peanut during the study did not seem to affect the result...
During the follow-up period 34% increased their IgE antibody
class...The subjects over 6 yrs of age showed a decrease in
peanut-specific IgE class over a 5-yr period...our results suggest
that follow-up and renewed testing is recommended, since there may
be a change in IgE antibody classes and clinical sensitivity over
time."234
(posted Oct. 18th, 2004)
-At the annual AAAA&I meeting held in San Diego, CA Feb. 23-27, 2007, Naimi et al. presented The Utility of Combining Skin Prick and specific IgE Antibody Testing as a Predictor of Clinical Reactivity to Milk, Egg and Peanut. For peanut, the specific IgE levels of <3kU/L and skin prick test wheal size of <5mm were associated with a 89% chance of passing an oral challenge to peanut. The authors conclude that by this combination they establish values for peanut with excellent predictive value but with higher cut-off values than has previously been reported. With these criteria, many children who are not truly allergic to peanut will be more likely to undergo a negative challenge, thereby preventing the unnecessary avoidance of the food (posted May 5th, 2007)
-Wainstein BK et al have an article entitled Combining skin prick, immediate skin application and specific-IgE testing in the diagnosis of peanut allergy in children in Pediatr Allergy Immunol. 2007 May;18(3):231-9. In their study, skin prick test specificity was 67% at >or=8 mm and 100% at >or=15 mm. The I-SAFT was 82% specific. A peanut specific-IgE level of 0.37 kU/l was 98% sensitive but 33% specific. A level of 10 kU/l was 100% specific. Combinations of a skin prick test of >or=8 mm with a positive I-SAFT (immediate skin application food test) and a peanut specific-IgE >or=0.37 kU/l were 88% specific with a sensitivity of 38%. Using challenge outcomes as the standard, available in vitro and in vivo diagnostic tests for peanut allergy have poor sensitivity and specificity and combining them does not significantly improve their clinical usefulness. Previously described diagnostic cut-off levels do not have general applicability. Allergy practitioners may need to interpret results of allergy tests in the context of their own practices. (posted May 27th, 2007)271
Previous studies have suggested various diagnostic cut-offs of allergy tests for the diagnosis of clinical peanut allergy in children. There are few data relating to the use of combinations of these tests in children. We aimed to determine the validity of previously reported diagnostic cut-off levels of peanut allergen skin tests and peanut specific-immunoglobulin (Ig) E, as well as the usefulness of combinations of these, for predicting clinical peanut allergy in our Allergy Clinic. Children attending the Allergy Clinic with a positive peanut skin prick test (SPT; n = 84) were included in the study. Immediate skin application food tests (I-SAFT) using 1 g of peanut butter (positive if any wheals were detected at 15 min), peanut specific-IgE levels and open-label peanut food challenges were performed. Fifty-two of 85 peanut challenges were positive.
-
-
Increase (?) in the
frequency and severity of reactions to
peanuts.
-The current increase in the prevalence of food allergies appears
to have several causes including better screening, improved
diagnosis and changes in both the techniques used by food
manufacturers and eating habits (1997).1
-Experience over the past decade suggests that the ready
availability and early introduction of highly allergenic foods (e.g.
peanuts and nuts) into the diet will only increase the number of
individuals suffering from hypersensitivity reactions to foods.
11
-Peanut and tree nut allergies are potentially life-threatening. .
. and appear to be increasing in prevalence
13.
-Increase in frequency of peanut allergy and fatal
cases have been reported
23.
Comment:
Dr. Rhoda Sheryl Kagan: The known prevalence of
the frequency and severity of reactions to peanuts is 0.6%-1.0%.
The medical literature suggests an increase, but no figures are
given. Bock, in a talk given in Montreal last June (1998) said
that the prevalence has not changed. (posted Oct. 1998)
-According to Emmett, Angus, Fry. et Lee, from Surrey, UK . . .
Peanut allergy is reported by 1 in 200 of the population and is
commoner in those reporting other allergies. The fact of similar
rates in children and adults argues against a recent marked rise in
prevalence.. . . . 73
(posted July 12th, 1999)
-Zeiger, in the Jan 2000 J Pediatr Gastroenterol
Nutr writes. . ."food allergy has increased in prevalence
during the past decade, and thus represents a major burden to our
young. . . Identifying and developing effective strategies to prevent
food and other allergic diseases represents a high priority for
medicine at this time because of the unbridled increase in the
prevalence and morbidity attributed to them."
90 (posted Jan 23d, 2000)
-The prevalence has increased substantially,
one in two-hundred 4-year-olds32
...related probably to the doubling and trebling of the prevalence of
allergic asthma, rhinitis and eczema in certain, mainly
"westernized," populations, according to Pamela W.
Ewan33.
-Drs Gideon Lack, and Jean Golding,
in a letter published in the British Medical Journal of Aug
1996, made the following comments about her article, "
Pamela W. Ewan makes the important statement that the incidence
of peanut and nut allergy is rising and that sensitisation seems
to occur early in life. Regrettably, she does not provide any
evidence to back her recommendation that "young allergic children
should avoid peanuts and nuts to prevent the development of this
allergy" and her extraordinary suggestion that avoidance should be
practised until the age of 7. There is no evidence that
avoiding foods during lactation or early childhood prevents
allergic sensitisation to these foods. 96
(posted July 26th, 2000)
-As mentioned earlier in this article, Dr Hugh A. Sampson, in the
editorial entitled, 'What should we be doing for children with
peanut allergy?' published in the Dec 2000 Journal of
Pediatrics begins with these words: "Most pediatric allergists
agree that the prevalance of food allergies, and peanut allergy in
particular, is increasing, although appropriate epidemiologic data to
substantiate this belief are lacking. The reason for this apparent
rise continues to elude us." 107
(posted Jan 6th, 2001)
-Rising prevalence of allergy to peanut in children: Data from
2 sequential cohorts is the title of a study published in the
Nov 2002 J Allergy Clin Immunol, by Grundy et al. To
determine whether allergy to peanut is on the increase, the authors
looked at changes in 2 sequential cohorts in the same geographic area
6 years apart. Of 2878 children born between Sept 1994 and Aug. 1996,
living on the Isle of Wight, 1273 completed questionnaires, 1246 had
skin prick tests at the age of 3 and 4 years. Those with positive
skin tests to peanut were subjected to oral challenges, unless there
was a history of immediate systemic reaction. The data was compared
with information on sensitization and clinical allergy to peanut
available from a previous cohort born in 1989 in the same
geographical area32.
- Results: There was a two-fold increase in reported
peanut allergy (0.5%[6/1218] to 1.0%[13/1273],
but the difference was nonsignificant. Peanut sensitization
increased 3-fold, with 41 (3.3%) of 1246 children sensitized in
1994 to 1996 compared with 11 (1.1%) of 981 sensitized 6 years
ago. Of 41 sensitized children in the current study, 10
reported a convincing clinical reaction to peanut, and 8 had
positive oral challenge results, giving an overall estimate of
peanut allergy of 1.5% (18/1246). Conclusions: Sensitization
to peanut had increased between 1989 and 1994 to 1996. There
was a strong but statistically nonsignificant trend for
increase in reported peanut alleregy.163
- -At the EAACI (European Academy of Allergology and Clinical
Immunology), Dr Arshad, co-author of the above study, presented
their findings as reported in DG Dispatch by Jill Stein:
Peanut
Allergy May Decrease with Age . He stated that contrary to
public opinion, peanut allergy does not necessarily start early
in life and children who are sensitized to peanuts at an early
age often lose this sensitivity in later childhood.' (posted
June 20th, 2003)
-
-
- Press Release, Dec 9th,
2003: Prevalence
of Peanut and Tree Nut allergies on the rise:New
research from the Journal of Allergy and Clinical
Immunology
The above press release is a follow-up to the following two articles published in the Dec, 2003 Journal of Allergy and Clinical Immunology:
- 1. Prevalence of peanut and tree nut allery in the
United States determined by means of a random digit dial
telephone survey: A 5-year follow-up study by Sicherer,
Munoz-Furlong and Sampson. .... in 2002 by sex and age and to
compare the results with prevalence estimates obtained 5 years
earlier.65
Out of 13,493 individuals involved, peanut allergy, tree nut
alleregy, or both was self-reported in 166 individuals (1.2%).
The overall prevalence rates were similar to those reported in
1997, also as far as severity, Applying conservative rules to
adjust for persons with unconvincing reactions and a
false-positive rate of the survey instrument, a final
prevalence estimate of 1.04% was obtained...Although the
rate of peanut allergy, tree nut allergy, or both was not
significantly different from 1997 to 2002 among adults, the
rate increased from 0.6% to 1.2% among children, primarily as a
result of an increase in reported allergy to peanut (0.4% in
1997 [12 of 2998] to 0.8% [26 of 3127] in
2002).198
- 2. The second article is by Kagan, et al, entitled
Prevalence of peanut allergy in primary-school children
in Montral, Canada. The prevalence of peanut allergy was
estimated by administering questionnaires re peanut allergy
to children in kindergarten through grade 3 in randomly
selected schools. The respondants were stratified as
follows: (1) peanut tolerant, (2) never-rarely ingested
peanut, (3) convincing history of peanut allergy, and (4)
uncertain history of peanut allergy. Groups 2, 3, and 4
underwent peanut skin prick tests (SPTs), and if the
responses were positive in groups 2 or 4, measurement of
peanut-specific IgE were undertaken. Children in group 3
with a positiv SPT response were considered allergic to
peanut without further testing. Children in groups 2 and 4
with peanut-specific IgE levels of less than 15kU/l
underwent oral peanut challenges.
- Results: Of the 7768 children surveyed, 4339
responded, 94.6% in group 1. The prevalence of peanut
allergy was 1.50%. When multiple imputation was used to
incorporate data on those responding to the questionnaire
but withdrawing before testing, the estimated prevalence
increased to 1.76%. When data re the peanut allergy status
of nonresponders (as declared to the school before the
study) were also incorporated, the estimated prevalence was
1.34%.199
-
- Conclusion of the authors: Our prevalence
study is the first in North America to corroborate
history with confirmatory testing and the largest
worldwide to incorporate these techniques. We have
shown that, even with conservative assumptions,
prevalence exceeds 1.0%
In the discussion of the paper, the authors state:
-
-
"Our study shows that the prevalence of peanut allergy is
higher than what has previously been reported in the only
other North american study65 (mentioned in the Sicherer et al study summarized above)
and in three European surveys, one of which is Tariq et
al reporting a 1.2% incidence of peanut allergy in
children32,
another is Emmett et al study that concludes
that "Peanut allergy is reported by 1 in 200 of the
population and is commoner in those reporting other
allergies. The fact of similar rates in children and
adults argues against a recent marked rise in
prevalence.. . . 73,
and the third being the Kanny et al 2001 paper where the
authors conclude that the prevalence of food allergy
is estimated at 3.24% in France, the study
emphasizing the increasing risk of food
allergy...128.
- They further state: It is possible that our study
suggests that the increasing peanut allergy prevalence
reported on the Isle of Wight is also occurring in
Norh America. The study they refer to is the Grundy et
al, paper entitlled Rising prevalence of allergy to
peanut in children: Data from 2 sequential cohorts
published in the Nov 2002 J Allergy Clin
Immunol. There was a two-fold increase in
reported peanut allergy (0.5%[6/1218] to
1.0%[13/1273], but the difference was
statistically nonsignificant. 163
(posted Dec 11th, 2003)
-
-
- -Here's an answer to a question posted on the Net in June
2003. "Are
peanut allergies for real?" It makes for a good read. Take a
look. here are some hightlights.
-
- -"Peanut allergies have been around forever, but peanut
phobia blew up out of nowhere. Ninety-four percent of the
journal articles I turned up by searching on "peanut" and
"allergy" in an on-line medical database (165 out of 176) were
published since January 1995. Now a week doesn't go by without
some new sign that peanut butter is to the 21st century what fleas
and rats were to the 14th."
-
- -"Is the danger real or just hype? Probably both. The
number of deaths in the U.S. due to food-related anaphylactic
shock is small, at most 200 annually, 80 percent of which
are due to peanuts or "tree nuts" (walnuts, pistachios, pecans,
etc). One UK study estimates that the annual risk that a
food-allergic child will die from a reaction is 1 in 800,000.
Food allergies aren't as common as people think. Surveys have
found that as many as 30 percent of respondents believe they
have a food allergy of some kind; the actual prevalence is 4 to
8 percent for kids and 1 to 2 percent for adults. Still, that's
a lot of people. An estimated 1.5 million Americans have peanut
allergies, and emergency rooms treat about 30,000 cases of
food-related anaphylactic shock each year. "
-"Are peanut allergies becoming more common? Many
researchers think so, but the evidence isn't overwhelming." (posted Jan 23d, 2004)
-
-
- -Grundy et al. presented a paper at the annual AAAA&I
Meeting held in San Francisco, Mar 19-23, 2004 entitled
Sensitization rates to food and aeroallergens amongst 1 year
olds in UK &endash; a population based study. The authors
state: "The reported prevalence of various manifestations of atopy
appears to be increasing. Early sensitization to various allergens
would be expected to parallel this rise. Many studies have
described the rates of sensitization in high-risk populations but
there is a paucity of large population based studies. We undertook
a whole population cohort study, investigating the rates of
sensitization to foods and aeroallergens in an unselected
population at the age of 1 year. Conclusion Despite the
rising prevalence of reported atopic manifestations, the rates of
sensitization to food and aeroallergens remain low in an
unselected population at the age of one year."
219
(posted April 26th, 2004)
-
- -"The apparent increase in peanut allergy has occurred
along with the apparent increase in allergic diseases in
children. This opinion was expressed by Gideon Lack, MD, of
the Imperial College, London, in The New England Journal of
Medicine (2003; 348:977-985) article on peanut allergy in
childhood. 171
-At the annual general meeting of the Canadian Society of Allergy and Clinical Immunology (CSACI) held in Montreal Oct. 26-29, 2006, Dr Scott Sicherer in his conference entitled 'Peanut Allergy: New Insights with Practical Implications for Diagnosis and Management' commented that the apparent increase in peanut allergy is not an isolated increase but a reflection of the increase in allergy in general, including food and respiratory allergies. (posted Oct 29, 2006)
-Here's an item that I just happened to hit on, that appeared in the Boston Globe Jan 30th, 2006: Peanut allergy epidemic may be overstated
By Dr. Darshak Sanghavi . In case the link is no longer accessible, here's a pdf version. (posted Oct 13th, 2007)
-
-
- The
impact of peanut allergy on children and
adults
-
- -At a poster session during the Annual Meeting of the
AAAA&I, Feb 26-March 3, 1999 in Orlando, MN Primeau,
RS Kagan, C. Dufresne, Y. St-Pierre, H. Lim, and A. Clarke
presented their evaluation of the impairment in quality of
life and family relations experienced by individuals with a
confirmed diagnosis of peanut allergy (PA) based on history and
skin test or RAST , compared with the impairment experienced by
patients with a chronic musculoskeletal disease (MSD). Impairment
of quality of life was assessed by the vertical visual analogue
scale (VVAS) [anchored from 0 (no disruption of daily
activities) to 100 (most disruption imaginable) and the Impact on
Family Questionnaire [0 (no impact) to 24 (maximum
impact)]. One hundred and thirty eight PA children with
disease duration of 4 years were compared with 61 MSD children and
37 PA adults and 41 MSD adults. . . Peanut allergic children
compared to MSD children with little physical disability have much
more impairment in their quality of life and family relations.
More importantly, even when compared with MSD children overall,
the impairment of peanut-allergic children is greater, attesting
to the substantial impact of peanut allergy.
-
- -A second element of this aspect was to evaluate which
factors were involved. Their conclusions were:
- Younger age of the children, closeness to the first
reaction, past history of anaphylactic reaction and presence of
other atopic conditions were all associated with increased
impairment of quality of life or family relations. Age at
the first allergic reaction, severity of the first allergic
reaction, presence of asthma and presence of other food
allergies were not associated with the severity of impairment
of quality of life and family relations. (posted March 13th,
1999)
-
- Dr. Marie-Noël Primeau asked to make the following
changes to the work cited above, i.e. that the patients in their
control group of musculoskeletal disease did not have MSD. The
adults ( >80%) had disseminated lupus erythematosus (LED or
SLE) and the children, (>70%), juvenile rheumatoid
arthritis.(posted March 24th, 1999)
-
This study has now been published in Clin Exp Allergy, in
Aug. 2000: The psychological burden of peanut
allergy as perceived by adults with peanut allergy and the parents
of peanut-allergic children. The authors conclude: "Given the
considerable disruption in daily activities and family relations
reported by the parents of peanut-allergic children, accurate
diagnosis of peanut allergy is essential. Our work should make
health care professionals dealing with children with confirmed
peanut allergy more aware of the support that these families may
require. Furthermore, we hope to motivate the food industry to
offer more 'peanut free' products to decrease the dietary
restrictions of these patients while minimizing their potential
for accidental ingestion. " 97
(posted Aug. 23d, 2000)
-
- -The following comment was published in the Dec 2001
Ann Allergy Asthma Immunol by Sicherer et al: Parental
perceptions of physical and psychological functioning were
measured with the Children's Health Questionnaire. "Childhood
food allergy has a significant impact on general health
perception, on the parents, and limitation on family activities.
Factors that influence reductions in theses scales include
associated atopic disease and the number of foods being
avoided."143
(posted Jan. 18th, 2002)
- -"Assessment of quality of life in children with peanut
allergy" is the title of an Oct. 2003 article in
Pediatric Allergy and Immunology by Avery NJ et al. The
authors measured the quality of life (QoL) of 20 children with
peanut allergy (PA) and 20 children with insulin-dependent
diabetus mellitus (IDDM) using two disease-specific QoL
questionnaires. Cameras were given to the subjects to record how
their QoL is affected over a 24 hr. period. Mean ages of subjects
was 9.0 and 10.4 years for PA and IDDM. Results:
- -Children with PA reported a poorer quality of life than
children with IDDM.
- -PA children reported more fear of an adverse event and
more anxiety about eating, especially when eating away from
home.
- -Most photographs related to food and management issues
and revealed difficulties for both groups regarding food
restrictions.
-PA subjects felt more threatened by potential hazards
within their environment, felt more restricted by their PA
regarding physical activities, and worried more about being
away from home. However, they felt safe when carrying
epinephrine kits and were positive about eating at familiar
restaurants.
-
- The authors concluded: The quality of life in
children with PA is more impaired than in children with
IDDM. Their anxiety may be considered useful in some
situations, promoting better adherence to allergen avoidance
advice and rescue plans. 197.
-
-At the annual AAAA&I Meeting held in San Francisco Mar
19-23, 2004, Stone et al have a poster entitled Parental
coping with childhood food allergies. Rationale Food allergies
affect up to 8% of children. Childhood food allergy can create
parental anxiety and alter family dynamics. A better understanding
of the extent of this problem is important for developing improved
educational and support methods for these families. Questionnaires
were distributed to parents attending a private allergy office
(n=135) or a food allergy support group (n=155). In addition to
demographic data, the questionnaires contained 20 questions
relating to parental coping. Three open-ended questions were also
asked regarding strengths and weaknesses of attending lectures on
food allergies. Results:
- 290 questionnaires were completed. The average age of the
children was 5.8 years (0.25-18 yrs); 70% were male, 30%
female.
- 94% of parents reported thinking about their children's
allergies daily, although it did not have a significant impact
on their sleep and did not impair their family's functioning.
- More parents feared for their child's safety because of
food allergies than riding in a car.
- The majority of parents actively sought information on food
allergies, including reading books and attending lectures on
food allergy.
- Most felt they had support from spouses and extended
families.
- Most parents did not feel that their child's psychological
or social development was affected by the food allergies.
- Conclusions: While most parents in this survey think about
their children's food allergies frequently, most actively seek
information on food allergies and appear to be reassured by this
information. Availability of educational material and support
groups is an important aspect of improving the care of children
with food allergy. 212
(posted Feb.16th, 2004)
-
- -ANTONIA C. LYONS & EMER M. E.FORDE, from Massey
University, New Zealand and Aston University, UK, in July
2004 published Food Allergy in Young Adults: Perceptions
and Psychological Effects in the Journal of Health
Psychology.
- The study examined the differences in awareness and
perceptions of food allergy and anxiety between young people
with and without a food allergy. Participants completed a
questionnaire which asked about their perceptions and knowledge
of allergies, perceived health competence and anxiety. Of
the 162 participants, 24 reported they were allergic to at
least one food; these people perceived that their
allergy had significantly less of an impact on their lives than
others believed it would. Allergy status interacted with
perceived health competence to affect anxiety. People with
an allergy and with high health competence reported the
greatest anxiety levels. Very few of the sample knew the
meaning of the term 'anaphylaxis'. Findings are discussed
in terms of health education implications and
possibilities.238
(posted Nov 20th, 2004)
- -At the annual AAAA&I meeting held in San Antonio, Texas,
Mar.18-22, 2005, Verreault, Kagan, Hourihane et al
presented Quality of life of Children with peanut allergy.
Using the QoL1(Quality of Life) Peanut Allergy
Questionnaire developed by Hourihane (Pediatric Allergy and
Immunology 2003;14:378-382) for children aged 4-6 yrs, a
parental perception of the child's QoL was elicited, and for
children > 7 yrs, the child's own perspective was elicited.
Children were considered peanut allergic if they had a clinical
reaction or a preanut-specific IgE > 14kU/L. Of 129
participants, 42 were aged 4-6 yrs; 21 had never ingested peanut,
27 had a mild reaction, 55 a moderate, and 26 a severe. The mean
age was 8.5 yrs. For all participants, the mean QoL1
was 58.2 (range 25-100; 100= worst outcome). Two visual analog
scales (QoL2 and QoL3) were also used (range
0-100; 100 = worst outcome). Results: 32.9 and 23.5 respectfully.
- Conclusions: Peanut allergic children experience
impaired quality of life. Best predictors of quality of
life did not include any characteristics of previous allergic
reactions or any demographic features. (posted April 24th,
2005)
-
-
- Is it a lifelong
allergy?
Contrairy to previous publications, peanut allergy is not
necessarily life-long.The following are publications that
appeared since 1998, studies that have shown that peanut
allergy can be outgrown:
1) to determine whether there are any differences between
children who remain mildly or moderately allergic to peanut (15
subjects) and children with similar histories but a negative
reaction on challenge with peanut (also 15 subjects) Hourihane
and coll. (1998) found that of the children that had lost
their allergy , 13 had allergy tests and 8 showed no allergy, the
other 5 still showed a positive test but reactions were not >
than 5 mm. IgE levels were the same in both groups. The group still
allergic showed allergies to other foods more so than the negative
group. The conclusion was: appropriately trained clinicians must be
prepared to challenge preschool children with peanut as some will be
tolerant despite a history of reactions to peanut and a positive skin
prick test to peanut 12.
See
complete article
Electronic
responses to this article:
- Confused parent
- Challenges for children with severe peanut allergic
responses
- Author's reply
- Too many questions
- How do you know for sure?
- Negative response to nut challenge does not mean nuts are safe
to eat.
- Comments:
- Dr. Rhoda Sheryl Kagan, and Dr. Anne Des Roches:
There's doubt as to the diagnosis of true peanut allergy in the
fifteen patients that have lost their allergy, which was based on
history only from the referring doctors. They don't seem to get to
the central allergy clinics until approx. 3 years later for
confirmation +/- challenge. One has to wonder. Also, there is
worry that the airplay this article will get will lead to a degree
of unrealistic optimism, until it is duplicated by others or its
methods clarified. (posted Oct. 1998)
- In a letter to the Editor of the British Journal of
Medicine Nov 7h, 1998, by T. David, professor of
Child Health, Manchester. Eng. entitled "Patients have not been
proved to grow out of peanut allergy," he too questions the
allergy histories of the patients in Hourihane's study - were they
really allergic in the first place? He refers to two studies, one
being Bock's 1987 article "Prospective appraisal of complaints of
adverse reactions to foods in children during the first three
years of life" where parents' reports could be confirmed in only
28% of 133 children with reported food intolerances29.
In the author's reply, referring to the "unresolved question" he
states that "our results suggest with some caution that some
children grow out of peanut allergy, and we accept that absolute
proof of resolution is absent." 30.
- 2) L'Actualité (Vol: 23 No: 10 15 juin
1998 62) in their section on Health and Medicine, had a
short paragraph entitled: "Une allergie reversible?" (A reversible
allergy?) The translation reads as follows: "Is your child
allergic to peanuts? Do not despair: he/she has a 40% chance of
not being allergic to peanuts at age four. British researchers
followed 14,210 children from birth to four years of age. One out
of 200 infants becomes allergic to peanuts by 20 months of
age.Nevertheless, at age four, two out of five spontaneously
outgrew the allergy.25
-
- A search of Medline did not reveal any mention of this
study, but:
- the study (ALSPAC or Avon Longitudinal Study of
Pregnancy and Childhood birth cohort study) was presented at
the annual AAAA&I meeting in Washington, DC, in March, 1998
by Golding, Fox and Lack on 14,210 children born over 21
months collated via questionnaires. Peanut allergy was identified
on the basis of questionnaires, skin testing and/or anti-IgE to
peanut, and confirmed by double-blind placebo-controlled food
challenges (DBPCFC).
- The cumulative prevalence of peanut allergy at 24 months
was 0.21% and at 48 months was +/- 0.31%.
- The mean age at first reaction was 20.5 months.
- All allergic children reacted upon first known exposure
to peanuts.
- 75% of reactions were due to eating and 25% to touching
peanut.
- Peanut butter was responsible for 40% of reactions, whole
nut for 41% and peanut containing foods for 19%.
- 11% of the group had siblings with peanut allergy.
- Allergy to other foods was reported by 50% and 38% of
children had egg allergy.
- The most common symptoms on DBPCFC were:
- nasal symptoms (62%),
- urticaria (hives) (54%),
- vomiting (31%).
- wheeze (15%)
- and stridor (difficult breathing) (7%).
- Two patients required intramuscular epinephrine and one
patient had a late-phase reaction.
- 41% (9/22) of children challenged were demonstrated to
have outgrown their allergy.
- Children who outgrew their allergy tended to present
earlier than those with persistent peanut allergy.
- The ones not having outgrown their allergy were
significantly more allergic with
- higher rates of eczema (100% vs 44%)
- asthma (85% vs 11%) and
- other food allergies (70% vs 33%) and they were more
sensitive on allergy tests.
-
- Conclusions:
Peanut allergy represents a significant problem by 2
years of age and that by 5 years nearly half of these children
will lose their allergy. (posted March 13th, 1999)
- This is not quite what was reported in an earlier study,
Bock and Atkins in 1989 published their evaluation of 32
patients that had a positive DBPCFC as well as a positive
skin test to peanuts. Follow-up challenges, conducted 2 to
14 years after the original challenge, showed that all
retained their sensitivity, confirming the peanut
sensitivity can be quite long-lasting 17
Peanut and tree nut allergies are potentially
life-threatening, rarely outgrown . . 13
56.
3) At the 1999 American
College of Allergy, Asthma & Immunology Annual Meeting held in
Chicago, Nov 11-17th, among the New Findings in Food Allergy Research
presentations, Dr Sami Bahna reported on:"Outgrowing"
Peanut Allergy. Recent studies indicate that peanut allergies,
which afflict approximately 1% of the US population, can be
"outgrown" by adolescence.12
Indeed, findings presented by J.M. Spergel, MD, PhD, suggest that
resolution is more likely to occur in patients with smaller skin test
reactions and clinical reactions limited to the epidermis. Spergel's
group subjected 38 patients with a clinical history of reaction prior
to evaluation and with a positive skin test, to peanut challenge.
Twenty-one patients persisted with positive challenge (PC) and 18
patients had a negative challenge (NC) despite positive skin
tests. One patient became tolerant by challenge while another
patient's reaction went from positive to negative. Both PC and NC
groups had equivalent medical backgrounds although none of the
patients with anaphylaxis became tolerant within the follow-up period
of 2 to 6 years. The most significant difference occurred, however,
in the size of the skin test -- the PC group experienced larger wheal
and flare (P < .005).This study confirms the findings of a few
other recent reports demonstrating that peanut sensitization can be
outgrown. Favorable factors include onset during childhood, low
degree of reactivity, and clinical manifestations other than systemic
anaphylaxis. (posted Nov 18th, 1999)
This study has since been published in the Dec 2000
Annals of Allergy, Asthma and Immunology 109
(posted Jan 21, 2001)
4) "The natural history of food allergy documents
that allergy to cow's milk, egg and soy frequently remit whereas
allergy to peanut, nuts and fish typically persist to
adulthood, although exceptions exist. Food allergen
avoidance subsequent to sensitization and manifestation of symptoms
appears to hasten tolerance; however, the immunologic mechanism
responsible for tolerance to one food group and not another is poorly
understood.90
(posted Jan 23d, 2000)
5)
At the annual meeting of the AAAA&I held in San Diego,
Mar 3-8th, 2000, Vander, Leek, Liu and Brock state: "Previous
studies have shown that peanut allergy is rarely outgrown, although
recent observations suggest that younger children with milder
reactions may lose their reactivity." The objectives of the study
they report on, were to "observe the frequency and nature of adverse
reactions due to accidental peanut exposure in young children with
previous clinical hypersensitivity, and to determine the potential
value of serum peanut-specific IgE antibody levels for ongoing
follow-up." Eight-two (82) children were identified with clinical
peanut hypersensitivity diagnosed before their 4th birthday. All had
positive skin tests. They were followed over a median 5.6 yrs (range
1.2 to 22.1 yrs), contacted yearly to track adverse reactions due to
accidental peanut exposure. IgE antibody levels were obtained in
42/82 subjects.
- The majority of young children with clinical peanut
hypersensitivity will have adverse reactions due to accidental
peanut exposure within 3 yrs of their initial evaluation.
In addition, it appears that young children who present with
only skin reactions are at risk for respiratory and/or
gastrointestinal involvement with subsequent peanut
exposure. Children who have had only cutaneous reactions
to peanut have lower peanut-IgE levels than those who have
respiratory and/or gastrointestinal involvement. (posted Mar
9th,2000)
6)
A joint group from Johns Hopkins (Skolnik et al) with H.
Sampson from Mont Sinai, at the annual AAAA&I meeting in San
Diego, Mar 3-8th, 2000, also reported on the duration of
peanut allergy in a study whose purpose was to determine the number
of children diagnosed with peanut allergy who became tolerant later
in life. Peanut-specific IgE (PN-IgE) quantification was done and
the ones with a titre of < 20 kU/L and no history of reaction in
the past year were asked to participate in a double-blind
placebo-controlled peanut challenge (DBPCPC) (unless the previous
reaction was severe, in which case a cut-off of < 10 kU/L was
used.) Some patients had open challenges. To date, 103 patients, age
range 4-17.5 yrs (median 6.5) have participated in the study. These
patients were diagnosed with peanut allergy from age 2 months to 10
yrs (median 1.5 yrs). Forty-four patients (43%) were identified as
definitely peanut allergic since their PN-IgE was > 20kU/L.
Twenty-one patients with a PN-IgE < 20 kU/L refused the challenge.
The remaining 38 patients participated in either a DBPCFC or an open
challenge. Skin tests were repeated before the challenge in 13/38
patients and four had turned negative. The median range of PN-IgE
of the patients challenged was 0.75 kU/L (range < 0.35
(undetectable) to 20.4 kU/L). Overall, 26 patients had a negative
challenge and are believed to have outgrown their peanut allergy
(ages 4-11.5 yrs (median 6), PN-IgE < 0.35 to 20.4kU/L (median
0.54). The remaining 12 experienced a positive challenge (ages 4-9.5
yrs ; median 5), PN-IgE < 0.35 to 11.6 (median 1.24 kU/L). 71% of
patients with a PN-IgE < 2 kU/L had a negative challenge. Of those
challenged, PN-IgE level for those who passed versus those who failed
were not different at the time of diagnosis or challenge. The
severity of the initial reactions were also similar, with both groups
including patients with moderate to severe anaphylaxis.
Conclusion : This study demonstrates that peanut
allergy is not necessarily life-long. Patients with very low
PN-IgE levels should be challenged in a medical setting to
determine whether they can now tolerate peanuts. (posted Mar
9th, 2000)
This study was continued and
published in the Feb 2001 J Allergy Clin Immunol
issue by Skolnik, Conover-Walker, Barnes Koerner, Sampson, Burks,
and Wood.106
- A total of 223 patients were evaluated, and of those,
- 85 participated in an oral peanut challenge.
- Forty-eight (21.5%) had a negative challenge, and were
believed to have outgrown their peanut allergy (aged 4-17.5
years [median 6 years]).
- Thirty seven failed the challenge (aged 4-13 years
[median 6.5 years]) Both groups had an IgE level less
than 20 kU/L.
- 41 patients with levels of IgE less than 20 kU/L declined
to undergo the challenge
- 97 were not eligible because their IgE levels were higher
than 20 kU/L or they had had a recent reaction
- 67% of patients with IgE levels less than 2 kU/L and 61%
with levels less than 5 kU/L had negative challenge
results.
-
- Conclusion:
- This study demonstrates that peanut allergy is outgrown
in about 21.5% of patients.Patients with low IgE levels should
be offered a peanut challenge in a medical setting to
demonstrate whether they can now tolerate peanuts.112
(posted Feb. 14th, 2001)
7) Rommy Koetzler, M.D. and Alexander C. Ferguson, M.D.
published their study entitled Outcome of Peanut Allergy in
Infancy: An Oral Challenge Study in School Age Children, in the
Canadian Journal of Allergy & Clincal Immunology, July
2000, Vol. 5 No.6. Fifteen children with documented peanut
reactions, and positve skin tests as infants were challenged with
increasing doses of emulsified peanut butter in serial doses of 10
µg to 5 g. increasing until symptoms or signs developed, or the
maximum dose reached. Results: 8 children had a mild reaction,
3 moderate, and none severe. Reactivity was unrelated to age at first
peanut contact or to current age. Current skin test size (wheal
diameter) was smaller in those with negative challenges, and
anti-peanut IgE was lower. Symptoms were elicited by doses of
10µg or greater (abdominal pain, tingling tongue, itchy throat,
nausea, itchy lips) whereas objective signs (vomiting, urticaria,
pruritis, facial oedema, and cough) required 100mg or more of peanut
butter. One subject had no reaction, and three had symptoms but no
objective signs with a 5 gm dose. If objective signs are taken as
evidence of persistent peanut allergy, 4/15 (27%) subjects appeared
to be tolerant to peanut. They conclude that "whereas allergy to
peanut tends to persist, the severity of reactions decreases - more
than trace amounts may be required to elicit a significant reaction
and a substantial proportion of children may be tolerant. A much
larger cohort of children and repeated challenge testing will be
required to confirm and validat theses findings. " (posted July 27th,
2000)
8) At the Sept.8-10, 2000 Annual Meeting of the
Canadian Society of Allergy and Clinical Immunology, Kerr PE and
Kagan RS, from the Dept of Allergy and Immunology, Montreal
Children's Hospital, presented, at the Poster Session, Resolution
of Peanut Allergy: A Case Report, the abstract of which appeared
in the Canadian Journal of Allergy and Clinical Immunology, Vol 5,
No 7, Sept 2000.
- They report the case of a 9-year-old boy who was diagnosed
with peanut allergy at 18 months of age (swelling and erythema
of the face, eyes, mouth, and lips 15 minutes after ingestion
of peanut butter; skin prick test was positive: 15/22
wheal/flare) Since diagnosis, he had avoided all nuts and
peanut products completely. Recently, he ingested a sauce with
a small amount of peanut in it and had no reaction. His parents
requested a re-assessment....A repeated skin prick test at age
9 remained positive for peanut: 9/18...At the family's request,
the child underwent an oral challenge. He tolerated graded
amounts of peanut flakes and subsequently ate a portion of
peanut butter on cookies without any symptoms. Since then, he
has resumed eating peanuts with no adverse reactions. This
case illustrates that a diagnosis of peanut allergy based on
clinical history and skin test can disappear over time.
Further studies are needed to identify the determinants of
lifelong versus resolving peanut allergy in order to guide
physicians as to which patients can safely be retested and
challenged. (posted Sept 12th, 2000.)
-This study was published in the Feb 2002 Annals of
the RCPSC (Royal College of Physicians and Surgeons of
Canada)
9) In the Oct 2000 J Allergy and Clin
Immunol , Dr. J. M. Kelso reports on the Resolution of peanut
allergy in a 3 year-old girl, diagnosed with documented peanut
allergy at 8 months of age after having reacted to peanut butter
with generalized urticaria. She was seen after having eaten a food
made with peanut flour. The test done with commercial peanut extract
and crude peanut were negative. She was challenged with peanut
butter to which she did not react. Dr Kelso "advised the parents
to re-introduce peanut products in her diet but to continue to be
prepared, for the time being, to treat a reaction." (see
'worsening of reaction after prolonged avoidance has been
described', below) ...that although previous studies have
suggested that peanut allergy is usually life-long, this patient
suggests that in rare cases the allergy can in fact resolve. It
will be interesting to see whether peanut allergy re-develops in this
child. Given the large burden that peanut avoidance imposes on
children and families (e.g. reading labels and carrying
epinephrine), it would seem reasonable to repeat peanut skin tests
in children allergic to peanut at some interval, especially if they
believe they have had uneventful accidental ingestions in the
interim." 98
(posted Oct 29th, 2000)
10) In the Dec. 2000 Pediatrics, Bock et
coll. followed 84 children with clinical peanut hypersensitivy
diagnosed before their fourth birthdays, contacted yearly for 5 years
to track adverse peanut reactions. Serum peanut-specific IgE
levels were determined in 51 of 83 subjects.
Results: fifty-eighy percent (31/53) of subjects
followed up to 5 years experienced adverse reactions from
accidental peanut exposure. Regardless of the nature of their
initial reaction, the majority with subsequent reactions (52%,
31/60) experienced potentially life-threatening symptoms. The
group with isolated skin symptoms (11/51, 22%) had lower serum
peanut-specific IgE levels than the group with respiratoiry and/or
gastrointestinal symptoms. (40/51, 78%)... Four selected
subjects had negative double-blind placebo-controlled food
challenge responses to peanuts during follow-up.105
(posted Dec. 21st, 2000)
11) At the Oct 2001 annual meeting of the CSACI
(Canadian Society of Allergy and Clinical Immunology) Dr. Rhoda Kagan
of the Allergy and Immunology Division, Montral Children's Hospital,
gave a talk on The Natural History of Food Allergy. Some of the
highlights: "8% of young children have food allergies but less than
2% of adults, suggesting that many children outgrow their allergies
as they get older. It varies with individual foods and its mechanism
remains unclear. Previously held beliefs that some food allergies are
always life-long have recently been challenged, leaving a greater
sense of optimism for the resolution of food allergy presenting in
early childhood." She cites Hourihane's article that appeared in 1998
and other studies since (see postings above). "The evolving
recognition of the natural history of peanut allergy offers a glimmer
of optimism for families and individuals with peanut allergy. Because
individuals with peanut allergy and their families carry the burden
of anaphylaxis risk and its attendant psychological consequences, the
possibility of resolution is encouraging." (taken from
Anaphylaxis Canada Newsletter- Winter 2001) (posted Dec 7th,
2001)
12) Spergel and Fiedler in the Dec 2001 Current
Opinion in Pediatrics published 'Natural history of peanut
allergy' in which they state..."studies in the past year have shown
that a subset of patients with peanut allergy can become tolerant
to peanut. The patients with the milder reactions on presentation
have a better chance to develop tolerance to peanuts than the
patients whose first reaction is anaphylaxis...the natural history of
peanut allergy is evolving."139
(posted Dec 31st, 2001)
See
also: Prognosis
of Severe Food Allergies
Discussion
on outgrowing peanut
sensitivity
by Dr. Barry Zimmerman
13) "Peanut allergy may resolve in
approximately 15% of selected children atttending an allergy
clinic run by general paediatricians in a district general hospital.
Food challenge constitutes the appropriate way of removing the burden
that comes with a diagnosis of peanut allergy and enables dietary
restriction to cease." according to Rangaraj S et al, authors of a
publication in Pediatr Allergy Immunol Oct.
2004.232
(posted Oct. 18th,
2004)
14)"Resolution of peanut allergy
following bone marrow transplantation for primary immunodeficiency"
is the title of a publication by Hourihane, JO et al, in
Allergy April 2005. They report the case of "a boy with
peanut allergy who required a bone marow transplant (BMT) for
combined immunodeficiency. A food challenge, 2 years after
transplant, showed that his peanut allergy had resolved. Allergic
disorders constitute a form of immune deviation and while we do not
advocate BMT as a treatment for peanut allergy, we believe this case
provides an insight into the basic mechanisms involved in food
allergy." 244
(posted May 9th, 2005)
-Early clinical predictors of remission of peanut allergy in children. Ho MH, Wong WH, Heine RG, Hosking CS, Hill DJ, Allen KJ. studied consecutive patients less than 2 years of age with peanut allergy were identified on the basis of skin prick test (SPT) wheal size of 95% positive predictive value or greater. Baseline SPT responses to peanuts, tree nuts, and sesame and serum peanut-specific IgE antibody levels were documented, and follow-up studies were conducted at 1- to 2-year intervals for up to 8 years. Peanut food challenges were performed when SPT responses decreased to less than the 95% positive predictive value for peanut allergy.
RESULTS: SPT wheal diameters to peanut extract of 6 mm or greater and peanut-specific IgE antibody of 3 kUA/L or greater before the age of 2 years were independent predictors of persistent peanut allergy. Mean SPT wheal diameters of nonremitters increased whereas those of remitters decreased between 1 and 4 years of age. Twenty-one percent of young children with peanut allergy became clinically tolerant by age 5 years.
CONCLUSIONS: Remission of peanut allergy can be predicted by low levels of IgE antibodies to peanut in the first 2 years of life or decreasing levels of IgE sensitization by the age of 3 years. 283(posted Feb 17th, 2008)
Peanut
Allergies, Thought Outgrown, Can
Return
-(HealthScoutNews)=followiing the Nov 7,
2002 correspondance in the New England Journal of Medicine
by Sicherer SH et al. entitled Recurrent
peanut allergy
where the authors offer an
institutionally approved research protocol for double-blind,
placebo-controlled oral food challenges for use in children older
than 3.5 yers of age who have been allergic to peanuts and who have a
clinical profile consistent with potential resolution of peanut
allergy, as defined by the absence of recent reactions and a serum
peanut-specific IgE antibody concentration of less than 10
kU/:L.112
- They describe 3 patients who
tolerated peanuts during such a challenge...who went on to
have recurrence of peanut allergy. In the year after
having no allergic reaction on oral challenge, the boys ate
peanuts infrequently and in small quantities. The
recurrence of peanut allergy was documented in one patient
by a repeated challenge that elicited a generalized
reaction, in the second patient by repeated mild reactions
and a concentration of peanut-specific IgE antibody (15kU/l)
that was highly (>95%) predictive of clinical reactions,
and in the third patient by a severe reaction and recurrence
of sensitization.
- The authors can only speculate as to
why these children became resensitized. Although they were
not reactive, they were ingesting only small amounts of peanut
intermittently - a regimen that is typically considered to be
sensitizing. This regimen contrasts with typical regimens
designed to build tolerance (which entail the continuous
administration of small doses or the intermittent
administration of large doses). These 3 patients were
evaluated after 44 children entered the authors' ongoing study
of the resolution of peanut allergy. At that time, 26 children
had no allergic reaction on oral challenge, and follow-up (mean
duration, 15 months) in 21 children revealed that only 10
routinely ate peanuts. This observation is worrisome if the
aforementioned hypothesis is correct.
- The clinical ramifications of
the authors' observations are profound and may apply to
other foods as well as to peanuts. Recurrence of peanut
allregy is possible even when it has been shown to have
resolved. It seems prudent to maintain access to emergency
medications, such as self-injectable epinephrine, for
patients with resolved peanut allergy until peanuts are
routinely tolerated in relevant quantities for at least one
to two years. 164
(posted Nov 15th,
2002)
-
- -Here's an interesting item that
appeared in The Medical Post April 8,
2003: Tell
kids who outgrow allergy to eat more peanuts. Continued
exposure may keep them from becoming allergic again.
"Recent studies have shown about 20% of children outgrow
their allergy to peanuts. However, new evidence is emerging
that some of those children become allergic again. To avoid
that, Dr. Jeffrey Factor thinks kids who outgrow their allergy
should eat more peanuts." (posted July 4th, 2003)
Monthly
Ingestion Appears To Boost Peanut Tolerance In Children Who
Outgrow Peanut Allergy. According to researchers
at the Johns Hopkins Children's Center, children who outgrow
peanut allergy have a slight chance of recurrence, but
the risk is much lower in children who frequently eat peanuts
or peanut products. J Allergy and Clin Immunol
Nov 2004: Peanut allergy: Recurrence and its
management-David M. Fleischer, MD, Mary Kay Conover-Walker,
Lynn Christie, MS, RD, LD, A. Wesley Burks, MD, Robert A. Wood,
MD237
(posted Nov 10th, 2004)
-In the July 2003 J Allergy Clin
Immunol, Fleischer et al have an article entiltled The
natural progression of peanut allergy: Resolution and the
possibility of recurrence where they extend the data
reporting that 20% of youngsters with peanut allergy,
especially when diagnosed at a young age, might lose their
reactivity over time (summerized above106)
They report the loss of reactiviy at various levels of
specific peanut antibody in serum.
- Patients with peanut-IgE levels of 5 or less were offered a
peanut challenge. Those who passed were further evaluated by
questionnaire to assess reintroduction of peanut into their
diet and whether any recurrence has occurred.
- Results:
- -Eighty-four patients were evaluated, and 80 underwent
complete analysis.
- -Fifty-five percent with peanut-IgE levels of 5 or
less and 63% with peanut-IgE levels of 2 or less passed
challenges, compared to 61% and 67%, respectively, in
our previous study.
-The 4 additional patients passed peanut challenges in
this study after previously failing.
- -Three patients with initial anaphylactic
reactions and 2 patients with initial peanut-IgE levels
greater than 70 passed their challenge.
Follow-up of those who passed in both studies showed that
the majority of patients reintroduced peanut into their
diet, but that continued label reading, infrequent/limited
ingestion, and aversion to peanut were all common in this
population. Two patients had suspected subsequent reactions to
peanut after passing their challenge.
- Conclusions:
- Patients with a history of peanut allergy and
peanut-IgE levels of 5 or less have at least a 50% chance of
outgrowing their allergy. Recurrence of peanut allergy may
occur but appears to be uncommon.178
(posted July 11, 2003)
-
-
-
- -At a poster session at the AAAA&I Annual Meeting held
in San Francisco Mar 19-23d, 2004, Kerr PE and Ham Pong
A presented Peanut re-sensitiztion after negative skin tests
and negative oral challenge. They report 4 patients, three
of which had never ingested peanut but had positive
prick-skin tests between the ages of 13 months and 3 years.
The fourth patient had hives with peanut and a positive skin
test at 13 months. All patients developed negative skin
tests at ages 4-5.5 yrs at which time they all tolerated oral
challenge. Three patients refused to eat peanuts after the
challenge but between 1-6 yrs later ingested peanut and had
allergic reactions... nausea, vomiting, wheezing and sore
throat, or throat swelling. The fourth patient tolerated
peanut twice within a week of the oral challenge then
developed abdominal cramps and vomiting on two further
ingestions of peanut.
- Discussion: ...These cases highlight the need for parent
and patient education regarding the possibility of
re-sensitization after negative prick-skin tests and negative
challenge. Patients need to be instructed to continue to carry
epinephrine until they are regularly consuming peanut without
reactions.208
(posted Feb 15th, 2004)
-
- -At the same AAAA&I Meeting in San Francisco, Mar
19-23, 2004, Lidman, Watson, Simons and Becker had a poster,
Reactions to food in children recurs after negative oral
challenge. To determine if patients sensitized to food
remain tolerant after negative food challenge, they looked at
302 children < 16 years of age who had negative food challenges
between 1996 and 2003. They randomly reviewed 107 of them
(35%) with 121 challenges. 14 (12%) < 6 months from
challenge were excluded. 28 (23%) were lost to follow-up.
Complete data were available for 59 (47%):
- 40/59 (68%) regularly ate the food with no problem.
- 4/59 (7%) subsequently reacted, all with egg (4/18;
22%), and all to raw or less well cooked egg;
- 1/4 completely avoided egg and 3/4 tolerated egg in baked
goods.
- In spite of no reaction, 2/26 previously peanut allergic
continued to completely avoid peanut and 10/26 had peanut
< weekly.
- All 15 patients with negative milk challenge tolerated
and continued to regularly consume milk.
-
- Conclusions: Subjects with negative egg challenge
were more likely to react again than subjects with negative
peanut or milk challenge. Peanut allergy remains a concern
for many patients, even with a negative challenge.
Allergists should consider a second challenge for egg and/or
peanut allergic patients. 209
(posted Feb 15th, 2004)
-
- -Again, at a poster session of the same AAAA&I Annual
meeting, Mar 19-23, 2004, Fleischer, Conover-Walker and
Wood presented Peanut allergy: Recurrence and its
management. Rationale: Since peanut allergy may recur and
recurrence risk may be increased due to limited consumption
of peanut after allergy resolution, they re-examined
children who outgrew their allergy over the past 7 years to
determine their current allergy status. Thirty-one patients
(aged 5.5-21.4 years) with a follow-up period of 0.8-5.7 years
(after a negative challenge) were evaluated.
- One patient with a peanut IgE level of 1.1 kU/l at
initial challenge at age 4.5 years and who rarely consumed
peanut after resolution, had anaphylaxis to peanut 1.8 years
later and has a current peanut-IgE level > 100.
- Seven patients with peanut -IgE levels from <0.35 to
17.1 eat peanut frequently and continue to tolerate
it.
- Six patients with peanut-IgE levels from < 0.35 to 54
and eat peanut rarely passed DBPCFCs to peanut.
- Seventeen patients with peanut-IgE levels from 0.35 to
7.3 eat peanut rarely, have yet to undergo a DBPCFC.
-
- Conclusions: Children with resolved peanut allergy
may be at risk for recurrence. Monitoring peanut CAP-RASTs
of children with resolved peanut allergy may not be useful
because some children continue to be peanut tolerant despite
high peanut-IgE levels. 210
(posted Feb 15th, 2004)
- The authors (along with Christie L.and Burks AW)
published their findings in the Nov 2004 J Allergy
Clin Immunol. Their results:
- Sixty-eight patients were evaluated. Forty-seven
patients continued to tolerate peanut, of whom 34
ingested concentrated peanut products at least once per
month and 13 ate peanut infrequently or in limited
amounts but passed a DBPCFC.
- The status of 18 patients was indeterminate because
they ate peanut infrequently or in limited amounts and
declined to have a DBPCFC.
- After excluding 12 patients originally diagnosed with
peanut allergy based solely on a positive skin prick test
or peanut-specific IgE level, 3 of 15 patients who
consumed peanut infrequently or in limited amounts had
recurrences, compared with no recurrences in the 23
patients who ate peanut frequently ( P = .025). The
recurrence rate was 7.9 (95% CI, 1.7% to 21.4%).
- CONCLUSION: Children who outgrow peanut allergy
are at risk for recurrence, and this risk is
significantly higher for patients who continue largely to
avoid peanut after resolution of their allergy. On
the basis of these findings, we now recommend that
patients eat peanut frequently and carry epinephrine
indefinitely until they have demonstrated ongoing peanut
tolerance.239
(posted Dec 6th, 2004)
-In Pediatr Allergy Immunol. 2006 Dec;17(8):601-5. Eigenmann et al have an article entitled Continuing food-avoidance diets after negative food challenges. Here's part of the abstract: 'Negative food challenges for follow-up in patients previously diagnosed with food allergy should logically be followed by a normal diet. However, all patients do not reintroduce the food.Patients with a negative food challenge were sent a questionnaire by mail. Items in the questionnaire included the symptoms at diagnosis, the duration of the diet, the fear of an accidental reaction during the avoidance diet and how it influenced the social life. Patients were also asked if the food was reintroduced after the negative food challenge, and if not, for which reasons. In 25.4% of the questionnaires (18/71) respondents reported that the food was not reintroduced. Patients with a previous diagnosis of peanut allergy tended to reintroduce the food less frequently than patients allergic to other foods. However, neither the severity of the initial reaction, the anxiety of an accidental reaction during the avoidance diet, nor a prolonged avoidance diet did influence the decision to reintroduce the food. Among other reasons listed, fears of persistence of allergies, with recurrent pruritus or non-specific skin rashes after eating the food, were reported in 12.7% of the total number of questionnaires. Patients who reintroduced the food reported that their social life generally improved. One quarter of previously allergic patients continue a food avoidance diet despite a negative challenge. We suggest reassessing food consumption in all patients after a negative food challenge, and in those still avoiding the specific food to consider a repeated challenge test. (posted Jan. 5th, 2007)
-
-Worsening of reaction
after prolonged avoidance:
-An interesting feature of food allergy in general, although
unusual, "worsening of reaction after prolonged avoidance has been
described.27
. .David reported 4 children with atopic dermatitis (eczema) who
had foods to which they were allergic re-introduced into their diets,
and they experienced anaphylactic reactions74.
. ." These are comments made by the authors (Oppenheimer JJ, and
Bock, SA) in a report about an 8 year-old child with a history of
milk-induced exacerbation of atopic dermatitis who, after 18 months
of avoidance, experienced significant increase in her reactivity. The
communication is titled"The ice cream parlor challenge could be a
killer" published in the J Allergy Clin Immunol
1998;102:325-6. 75
(posted July 8th, 1999)
Link
between asthma and peanut allergy
- Is there a link between having asthma
and the intensity of the allergic reaction caused by peanut?
- According to the medical publications on
this aspect, particularly regarding anaphylactic reactions
reported to peanuts, the severity of the reaction seems to be
directly related to the atopy the patient has (presence of total
allergies), in other words, the most severe reactions reported
occurred in patients that had other food allergies and
environmental allergies, the latter ones responsible in great part
for the asthma.
- In 1988, Yunginger et al, of the
Dept of Pediatrics, Mayo Medical School, Clinic and Foundation,
published their findings on fatal food-induced anaphylaxis (rarely
reported at that time.) . . . in 16 months, they identified 7 such
cases (5 males and two females, aged 11 to 43 years). All
victims were atopic with multiple prior anaphylactic episodes
after ingestion of the incriminated food (peanut (4); pecan
(1); crab (1); fish (1). Factors contributing to the severity of
individual reactions included denial of symptoms, concomitant
intake of alcohol, reliance on oral antihistamines alone to treat
symptoms, and adrenal suppression by chronic glucocorticoid
therapy for coexisting asthma (reduction of immune defense due
to long-term use of inhaled cortisone preparations). . . each case
showed elevated levels of IgE antibodies to the incriminated
foods.62
- In 1992, Sampson, Mendelson and
Rosen, of the Division of Pediatric Allergy, Johns Hopkins
University School of Medicine, identified 6 chldren and
adolescents who died of anaphylactic reactions to foods and seven
others who nearly died and required intensive care. . . Of the 13
children and adolescents (age range, 2 to 17 years) 12 had
asthma that was well controlled. All had known food allergies,
but had unknowingly ingested the foods responsible for the
reactions. The reactions were to peanuts (four patients),
nuts (six patients), eggs (one patient) and milk (two
patients), all of which were contained in candy, cookies, and
pastry. 63
- Hourihane, Kilburn, Dean and Warner, in their 1997
publication: Clinical characterisitcs of peanut allergy
2
support this. There is no figure or table in the paper, but in a
personal communication Dr Hourihane sent the following
information: in 525 subjects who have had more than one
reaction to peanuts: mild reactions occurred in 47
non-asthmatics versus 45 in asthmatics; moderate reactions in 65
asthmatics versus 168 in non-asthmatics, but severe reactions
occurred in 187 asthmatics versus 78 in non-asthmatics!!. In
total, reactions occurred in 335 asthmatics versus 190 in
non-asthmatics.
- Pumphrey en 1996 also showed an association between atopy
including asthma, with reactions to foods and with younger age in
a series of anaphylactic reactions.64
- Sicherer, Burks et Sampson, in 1998, in
Pediatrics, showed 74% of subjects had asthma but the link
with severity of reaction was not reported. 13
- "I think the link between asthma and severe reactions is
convincing and is widely supported by those in the field
(admittedly anecdotally). It is certainly taken seriously by all
the leaders as an index of the need for adrenaline rescue
medication supply and training." (Hourihane, personal
communication) (posted April 8th, 1999)
- -See also the study from Sweden in the chapter on
'prevalence of peanut allergy' (above) posted May 13th, 1999
68
- -See more on peanut allergy and asthma further down in
the section on 'dealing with peanut allergy', when to give
epinephrine (Dr Hugh Sampson's article)
- -See the excellent review of this topic by Dr. Barry
Zimmerman: The
association between anaphylaxis and asthma
(posted Nov 6th, 2002)
- In the July 2003 J Allergy Clin Immunol , Graham
Roberts, et al. published : Food allergy as a risk factor for
life-threatening asthma in childhood: A case-controlled
study where they conclude that this study demonstrates that
poorly controlled asthma and food allergy (mostly to peanuts) are
significant risk factors for life-threatening asthma. More
intensive management of this high risk group of children might
help to reduce future morbidity and mortality.179
(posted July 11th, 2003)
- - in Pediatr Pulmonol. 2007 Jun;42(6):489-95, Simpson AB, Glutting J, Yousef E. published Food allergy and asthma morbidity in children. The authors ' studied the independent effect that allergy to egg, milk, fish, and peanut has on the number of hospitalizations and courses of systemic steroids in children with asthma.'
RESULTS: Peanut and milk allergies were both associated with increased number of hospitalizations (P=0.009, 0.016), and milk allergy was associated with increased use of systemic steroids (P=0.001). CONCLUSION: Peanut and milk allergies were associated with increased hospitalization and steroid use and may serve as early markers for increased asthma morbidity. 277(posted Aug 3d. 2007)
-
What
about reactions occurring by simply being in the presence of peanuts
or exposed to the odor of
peanuts?
-There's no mention in the above references regarding contact with
peanuts other than by ingestion and by contact with intact
skin10
, although Hourihane refers to "anecdotal reports (not supported
by challenge studies) of subjects reacting strongly to the smell of
peanuts or to being in the vicinity of an open jar of peanut butter.
58.
59
The dose of presumably airborne peanut protein involved in these
reactions must be very low. The more common scenario is an
allergic reaction after a minimal contact with peanuts 2
, through intact skin (e.g., being touched by someone who has handled
peanuts, accidental ingestion of small amounts of peanut protein, or
eating bread buttered with a knife previously used to make a peanut
butter sandwich for someone else)." (1996)
-In the May 2001 Ann Allergy Asthma Immunol , Tan,
Sher, Good, and Bahna report on "Severe food allergies by skin
contact." According to the authors, "while ingestion is the
principal route for food allergens, yet some highly sensitive
patients may develop severe symptoms upon skin contact." Five
cases, infants, are described with severe reactions to
milk, egg white, lentils, peas, and peanut butter occurring by
skin contact, or inhalation, while being breast-fed in four cases.
The symptoms reported range from eczema, urticaria, angioedema and
breathing problems. Each case had a strong family history of
allergy, early age of onset, very high total serum IgE, and strong
reactivity to the foods involved by skin prick test or RAST.
- Conclusion: Severe food allergic reactions can occur
from exposure to minute quantities of allergen by skin contact
or inhalation.129
(posted Aug 1st, 2001)
-On Feb 23d, 2002, the AQAA (Association
Québécoise des Allergies Alimentaires) held its annual
Allergy Day at Hôpital Ste-Justine de Montréal. Dr
Marie-Noël Primeau, pediatric allergist of the hospital,
gave a talk on Anaphylaxis and adverse reactions to the odor of
foods. "ANAPHYLAXIE ET RÉACTION À L'ODEUR DES
ALIMENTS". The question of adverse reactions to the odor of certain
foods is not clear. Firstly, there is little information on this in
the medical literature. Furthermore, because such reactions are
rare, the data reported can be applied to only a small number of
allergic individuals. Management and recommendations cannot be
defined specifically at this point in time. Each case must be
evaluated separately. Studies have shown that allergenic particles
of certain foods could be air-borne. But this does not mean that
these particles will cause a reaction in individuals allergic to the
particular food by inhalation. Dr Primeau's conclusion was
that adverse reactions can occur by simply being exposed to the
odor of foods, but they are exceptional. Because this type of
reaction is usually mild, limited to the skin or respiratory
system, Dr Primeau suggested that the approach in the
treatment of such reactions should be conservatory, and no strict
avoidance measures undertaken especially if the allergic individual
has never reacted to the odor or being in the presence of the food in
question. If this type of reaction does occur, it should be
brought to the attention of the allergist who will be able to assess
its importance and prescribe accordingly. (translation of comments
posted at the Allergique.org website Mar 11, 2002) (posted here
Mar 22, 2002)
- -In the July 2003 J Allergy Clin Immunol,
Simonte et al report a study, Relevance of casual contact with
peanut butter in children with peanut allergy the objective
being to determine the clinical relevance of exposure to peanut
butter by means of inhalation and skin contact in children with
peanut allergy. Children with significant peanut allergy (recent
peanut-specific IgE antibody concentration >50 kIU/L or
evidence of peanut-specific IgE antibody and one of the following:
clinical anaphylaxis, a reported inhalation-contact reaction, or
positive double-blind, placebo-controlled oral challenge result to
peanut) underwent double-blind, placebo-controlled, randomized
exposures to peanut butter by means of contact with intact skin
(0.2 mL pressed flat for 1 minute) and inhalation (surface area of
6.3 square inches 12 inches from the face for 10 minutes). Placebo
challenges were performed by using soy butter mixed with histamine
(contact), and scent was masked with soy butter, tuna, and mint
(inhalation).
- Results: Thirty children underwent the challenges (median
age, 7.7 years; median peanut IgE level, >100 kIU/L; 13 with
prior
- history of contact and 11 with inhalation reactions).
None experienced a systemic or respiratory reaction.
Erythema (3 subjects),
- pruritus without erythema (5 subjects), and wheal-and-flare
reactions (2 subjects) developed only at the site of skin
contact
- with peanut butter. From this number of participants, it
can be stated with 96% confidence that at least 90% of highly
sensitive children with peanut allergy would not experience a
systemic-respiratory reaction from casual exposure to peanut
butter.
- Conclusions: Casual exposure to peanut butter is
unlikely to elicit significant allergic reactions. The
results cannot be generalized to larger exposures or to contact
with peanut in other forms (flour and roasted
peanuts).180
(posted July 11th, 2003)
-
- -In the Bangor News, Sept 28, 2004, Dr.Paul A.Shapero,
M. D., an allergist in Bangor, Maine wrote "Some
perspectives on peanut allergy". where he states "inhalation
of peanut protein can cause allergic reactions but usually not
systemic anaphylaxis while odors can cause conditioned physiologic
responses... odors are not capable of causing allergic reactions."
(posted Oct 1st, 2004)
-
Commercial
airlines and peanuts
- -At the annual meeting of the AAAA&I (Feb. 1999 in
Orlando) Sicherer, Furlong, DeSimone, and Sampson presented a
paper entitled: "Peanut Allergic Reactions on Commercial
Airlines." The purpose of the study was to describe the
clinical characteristics of allergic reactions to peanut (PN) on
airplanes. Participants in the National Peanut and Tree Nut
Allergy Registry (PAR) who indicated an allergic reaction were
interviewed by telephone.
- 62 of 3,704 PAR registrants indicated a reaction on an
airplane.
- 42 patients or parental surrogates consented to further
questioning (median age of affected: 2 yrs, range 6
mo-50yrs).
- Of these, 31 reacted to PN, 3 to tree nuts, and 8 to uncertain
exposures, suspected PN.
- Exposures occurred by mouth (20), skin (8), and inhalation
(14).
- Reactions generally occurred within 10 minutes of exposure
(32/42).
- Reaction severity correlated with exposure route (mouth >
inhalation > skin).
- The causal food was generally served by the airline
(37/42).
- Medications were given in flight to 20 patients (epinephrine
to 6) and to an additional 14 on landing/gate return (including IV
to 2, one forcing a return to the gate), totaling 81%
treated.
- Flight crews were notified in 33% of reactions.
- During 10 PN allergic inhalation reactions, > 25 passengers
were estimated to be eating PN at the time of reaction.
- Initial symptoms generally involved the upper airway with
progression to skin or further lower respiratory reactions (no
gastrointestinal symptoms).
- 2 subjects were given epinephrine in flight.
- Asthma was previously diagnosed in 6 patients.
Conclusion: Food (peanut and nut) allergic reactions
occurred during commercial flights but airline personnel were
notified in only 33% of cases. Reactions were frequently severe,
requiring medication including epinephrine. Severe reactions were
primarily due to accidental ingestion, but respiratory reactions
occurred from inhalation when many passengers were consuming PN.
(posted April 2nd, 1999)
I e-mailed Dr. Hourihane, asking his opinion on the
importance of peanut odor, and this was his response: "I am not
personally aware of proven anaphylaxis associated with the smell
but it is often related by parents that the child has become
lethargic and clingy after entering a room with peanuts open in
the room. This cannot be called anaphylaxis with any
confidence. My feeling is that some people really do
degranulate on inhaled exposure (Dr. Hourihane is referring to
degranulation of cells involved in allergic reactions,
specifically mastocytes, meaning they have a typical allergic
reaction) but the reactions are minor - usually upper airway
and eyes with some urticaria (hives) maybe. The major problem
when exposed like this is panic especially on planes and in
other confined spaces." (posted April 8th, 1999)
The paper presented at the Orlando Meeting of the AAAA&I
(summarized above) has now been published in the J Allergy and
Clin Immunol, July 1999, vol 104, 186-9.
Further comments from the authors: Allergic reactions to
peanuts and tree nuts caused by accidental ingestion, skin
contact, or inhalation occur during commercial flights. . .
most of the inhalation reactions described were not
life-threatening. However, when one considers the whole group
experiencing acute allergic reactions by ingestion and inhalation
to peanuts or tree nuts while on commercial airliners, the
importance of exercising caution and having emergency medication
available becomes apparent. 76(posted
Aug. 1st, 1999)
-In the same issue of the journal, John M. James, M.D. summarizes
the 'airline-peanut allergy' problem in an artilcle entitled
Airline snack foods: Tension in the peanut gallery. Here are
some of his remarks:
-. . . "there has been increasing concern and debate
about the potential for individuals with peanut allergy to
experience an allergic reaction while on a commercial airplane
that is serving peanuts and/or peanut-containing food. . . .The
cabin of a plane in flight is certainly a less than ideal
environment in which to recognize and properly manage a
potentially severe allergic reaction. . . In mid-1998, the
Department of Transportation (DOT) issued a proposal that would
have mandated that the 10 major US commercial airlines must
provide "peanut-free zones" for passengers with allergic reactions
to peanuts. . . This met great resistance from the Air
Transportation Association. . . the US Congress. . .the mandate
was never implemented, one of the reasons cited by members of the
Congress was the lack of published, scientific data describing
passengers with peanut allergy who had experienced allergic
reactions caused by airborne peanut allergen on commercial
airliners."
-Citing the paper by Sicherer and co-workers summarized above,
Dr James underlines that this paper "represents the first
published investigation describing the clinical characteristics of
allergic reactions to peanuts on commercial airliners in subjects
with peanut allergy. . . the self-reported allergic reactions,
however, were very consistent with allergy. . .this investigation
does not provide all the data needed to resolve this ongoing
debate, but it certainly provides a solid foundation to better
address these potentially life-threatening exposures and allergic
reactions."
-"There are some disturbing findings in this investigation.
First, why was there such a low level of notification of flight
crews and airline personnel?. . .Second, could other potential
irritants (eg. strong perfumes, passive tobacco smoke on clothing
of smokers, and cleaning agents) have contributed to the
inhalation reactions in some of the subjects, especially those
with asthma? . . Finally, 5 subjects received epinephrine while in
flight to manage severe allergic reactions. This observation
relates to another relevant debate focusing on the availability of
injectable epinephrine on board commercial airliners and the
availability of trained flight personnel to administer this
medication."
-"Two things are very clear to me as this debate continues to
develop: education and preparedness should prevail. . . In the
final analysis, more objective data and proper education will help
guide us in the ultimate resolution of this important debate and
lower the tension in the peanut gallery." 77
(posted Aug. 1st, 1999)
- -See also:
- -Out
of the Blue: Peanut allergies are a little-known
danger
(posted April 1st,
2002)
-
-
- Peanut
oil
-refined peanut oil (heat processed) is not allergenic (in
other words, it will not cause an allergic reaction in the
peanut-allergic individual). Of 10 peanut-allergic patients
challenged with peanut oil, none reacted to the protein-free oils.
Subsequent reports have indicated that oils contaminated with
peanut protein may indeed produce significant allergic reactions
in peanut-sensitive individuals. Cold-pressed oils are more likely
to contain peanut proteins than hot-pressed oils. (1997)
15
-Hourihane and co-workers evaluated two grades of peanut oil for a
large group of subjects with proven allergy to peanuts, in a
double-blind, crossover food challenge with crude peanut oil and
refined peanut oil. None of the 60 subjects reacted to the refined
oil; six (10%) reacted to the crude oil. They concluded that
crude peanut oil should continue to be avoided. Refined peanut oil
did not pose a risk to any of the subjects. Change in labeling to
distinguish the two grades are recommended 18.
-Another later study confirms these findings, and examined several
brands of walnut, almond, hazelnut, pistachio, and macadamia nut
oils. The oil extracts known to be from oils that had undergone less
processing at lower temperatures tended to demonstrate qualitatively
greater IgE binding (blood test proof of peanut-specific antibody)
and higher protein concentrations, posing a threat to patients with
allergy 19.
-On the other hand, Olszewski and coll. reported an allergy to
peanut oil by skin test, and by double-blind placebo controlled
challenges, concluding the presence of residual allergenic
proteins in crude and refined peanut oil, and that the increase
consumption of allergens in the form of peanut oil and fats can
contribute to the occurrence or persistence of symptoms and may be
suspected to increase the risk of sensitization 23,24.
- -How about peanut oil in vitamin A and D preparations:
according to a Feb 1999 Swedish study, sensitization to
peanut during childhood through consumption of vit A adn D in
oil-based solution seems unlikely.78
-
- -In a 1994 J Allergy Clin Immunol paper, Hoffman
and Collins-Williams studied various makes of peanut oil, and
found that refined, hot-pressed peanut oils are free of protein
but cold-processed peanut oils could cause reactions in peanut
allergic individuals. They concluded that: "Highly reactive
individuals should avoid foods prepared in or with peanut oils,
especially "health foods," which may be prepared with cold-pressed
or unrefined peanut oil that may be contaminated with peanut
protein." 95
(posted June 10th, 2000)
-
- -On June 7th, 2001, there was a item in the Montreal
Gazette entitled, "Doctors skeptical about peanut-allergy
theory." It dealt with comments by two Montreal doctors (Dr.
M. Katz and B. Moroz) regarding the theory proposed by Dr Gideon
Lack, from St Mary's Hospital in London, Eng. following the
findings of his study of children with peanut allergy. He told the
Royal Society of London that 9 out 10 children with peanut
allergy had previously suffered from eczema...and that children
who developed peanut allergies were 8 times more likely to have
been treated with creams containing peanut oil than kids who were
allergy-free. The peanut oil containing creams would be an
ideal way of setting up the allergy *. Lack also dismissed the
widespread belief that expectant mothers who eat nuts during
pregnancy risk passing the allergy to their babies. In fact, he
argued that avoiding peanuts during pregnancy might have the
opposite effect- encouraging the emergence of allergies when
children come into contact with nuts (this based on a follow-up of
14,000 mothers-to-be since 1991)...He estimates that peanut
allergy affects one in 100 children. (posted June 9th, 2001)
- *-See chapter above on 'sensitization to peanut -
other possible sources of sensitiztion'. Lack and others
presented a paper on this at the March 1998 Annual
Meeting of the AAAA&I held in Washington, DC.
-
- -In the Aug. 2001 publication of Cutis,
Yunginger and Calobrisi analyzed a topical cream containing
fluocinolone and refined peanut oil, among other ingredients and
reactivity in 14 peanut-allergic subjects. No immediate or delayed
skin test reactivity was demonstrated in any of the subjects
tested. This suggests that a refined peanut oil-containing
dermatologic preparation is safe to use, even in persons who are
sensitive to peanuts.132
(posted Sept 20th, 2001)
-
-
-
Link between
peanuts and other legumes, tree nuts, and soy
re other legumes:
- -peanut is a legume along with peas, beans, soy,
lentils, alfalfa. The very allergic individual may also react to
one or more of the other legumes, mostly to peas. Avoiding all
the legumes in the peanut allergic individual is not warranted,
and will not change the peanut sensitivity.
- -A peanut-allergic subject usually tolerates most members
of the legume family 36,
67
(posted April 18th, 1999).
- -In the Dec 2001 issue of the J Allergy Clin
Immunol, Sicherer SH in his article 'Clinical implications of
cross-reactive food allergens' has a guide depicting the
likelihood of reacting to a related food based on studies with
DBPCFC (challenges). If one is allergic to a legume, the risk
of reaction to at least one other legume is 5%. If allergic to a
tree nut, the risk of reaction to at least one other tree nut is
37%.144
(posted Jan 29th, 2002)
-
-
- re nuts:
-A questionnaire survey, examination, and blood levels of
peanut-specific IgE antibody of a total of 122 patients (63%
males; median age 8 years at time of study) with convincing histories
of at least one acute reaction (and at least one organ system
involved within 60 minutes of ingestion) reported in July 1998
by Sicherer, Burks and Sampson, showed the following:
- 68 had reactions only to peanuts.
- 20 only to nuts.
- 34 to both peanuts and nuts.
- Of those reacting to nuts, 34 had reactions to one, 12 to two,
and 8 to three or more different tree nuts, the most common being
walnut, almond and pecan.
- Initial reactions usually occurred at home (median age, 24
months for peanuts, and 62 months for nuts.)
- It was the result of first exposure to peanut in 72% of
cases.
- 89% of reactions involved the skin (urticaria [hives],
angioedema [swelling of throat, difficulty
swallowing])
- 52%: the respiratory tract (wheezing, throat tightness,
repetitive coughing, dyspnea [shortness of breath] )
- 32%: the gastrointestinal tract (vomiting, diarrhea).
- Two organ systems were affected in 31% of initial
reactions.
- All three systems in 21% of the reactions.
- 38 of the 190 first reactions to peanuts or nuts were
treated with an injection of epinephrine (adrenaline).
- Accidental ingestion
occurred in 55% of peanut allergic children (average of two
accidents per patient with an accidental ingestion) and in 30% of
tree nut allergic children over a median period of 5.5 years.
- Symptoms after accidental exposure were generally similar
to those at initial exposure. Accidents occurred commonly in
school but also at home and in restaurants. Modes of accidental
ingestion included sharing food, hidden ingredients,
cross-contamination and school craft projects using peanut butter.
- 83% of the children were breast-fed, with > 90% of the
mothers ingesting peanuts and at least one tree nut during
lactation.
- Among patients reporting no history of exposure (>60% of
patients for each tree nut), IgE antibodies were found to a
particular nut in 50% to 82% of patients and to peanuts in 100% of
patients.
- Conclusions:
-
- Acute allergic reactions to peanuts occur early in
life.
- Peanut and tree nut allergic reactions coexist in one third
of peanut allergic patients.
- Reactions frequently occur on first known exposure and
may be life-threatening requiring emergency treatment.
- Accidental ingestion is common, occurring frequently
outside the home and often requiring emergency treatment.
- Consequently, early diagnosis followed by education on
avoidance and treatment measures (including self-administered
epinephrine) is imperative 13.
- -More on the incidence of accidental ingestion of
peanuts:
-
-It is mentioned in many of the postings throughout this article, that accidental ingestion or exposure is very frequent (e.g. 13 above). At the AAAA&I Annual Meeting held in San Antonio, Texas March18-22, 2005, Yu et al reported their findings: Accidental ingestions in peanut allergic children. Of 129 children...12 children had 15 accidental exposures, yielding an annual rate of 9.3%....Seven reactions were mild, 5 moderate and 3 severe. (posted April 22nd, 2005).
- This study was continued and is published in J Allergy Clin Immunol. 2006 Aug;118(2):466-72. Epub 2006 May 30. Of 252 children, 62% were boys, with a mean age of 8.1 years (SD, 2.9). The mean age at diagnosis was 2.0 years (SD, 2.1). Thirty-five accidental exposures occurred in 29 children over a period of 244 patient-years, yielding an annual incidence rate of 14.3%. (posted Aug. 29th, 2006)
-
- These findings confirm my personal experience: on
follow-up visits of peanut-allergic children, accidental
ingestion occured rarely. Of 582 children seen between 1992
and 2001, only 9 reported accidental ingestion, or a little
over 1.6%.
-
- -In the July 2005 Ann Allergy Asthma Immunol.,
Goetz DW, Whisman BA, Goetz AD published Cross-reactivity among
edible nuts: double immunodiffusion, crossed
immunoelectrophoresis, and human specific igE serologic surveys.
- OBJECTIVE: To survey serologic cross-reactivities among
7 tree nuts (walnut, pecan, hazelnut, cashew, Brazil nut,
pistachio, and almond) and peanut.
- RESULTS: Among tree nuts, 2 groups with allergen
cross-reactivity were defined: (1) walnut, pecan, and hazelnut
and (2) hazelnut, cashew, Brazil nut, pistachio, and
almond...the same groupings of cross-reactive tree nuts
identified several less prominent nut-nut antigen
cross-reactivities between groups and with peanut.
- CONCLUSION: With few exceptions (notably limited
peanut cross-reactivity with pistachio and walnut), peanut
antigens did not serologically cross-react with tree nuts.
- Walnut, pecan, and hazelnut form a group of strongly
cross-reactive tree nuts. Hazelnut, cashew, Brazil nut,
pistachio, and almond form a group of moderately
cross-reactive tree nuts. Cross-reactivities between these
groups are less pronounced (notably limited cross-reactivity
of walnut and pecan with Brazil nut). The strongest
cross-reactivities among tree nuts follow botanical family
associations: (1) walnut and pecan in the family
juglandaceae and (2) cashew and pistachio in the family
anacardiaceae.256
(posted Nov 14th, 2005)
See also: "Prevalence of peanut and tree nut (TN) allergy in
the US determined by a random digit dial telephone
survey."65
(further down)
-
- -Pumphrey and coll. in the Sept 1999 Clin Exp
Allergy, "explored the pattern of specific IgE to three
distantly related nuts in patients of all ages with nut allergy
(peanut, hazelnut and brazil nut). From 1994 to 1998: 731
patients (age 7 months to 65 years, median 6.6 yrs) had
specific IgE (> 0.35kUA/L) to at least one of these
three nuts: 282 had IgE to one nut, 130 to two nuts, and 319
to all three nuts. . . very similar patterns were found in all
subgroups. .
- Conclusion: the probability of a patient with nut allergy
having specific IgE to a particular combination of peanut,
hazelnut and brazil nut is similar, whatever their age or sex.
The apparent increase in multiple nut reactivity with increasing
age may therefore be due to exposure of previously unchallenged
sensitivity. The frequency of multiple-nut specificity is
sufficiently high that patients should always be tested for
allergy to a range of nuts if they have a history of reacting to
any nut. " 83
(posted Sept 6th, 1999)
-
- The natural history of tree
nuts
-
- -Fleischer et al have an article with the above
title in the Nov 2005 J Allergy Clin Immunol. The
abstract reads...'Although 20% of children outgrow peanut allergy,
the natural history of tree nut (TN) allergy has not been well
studied... Two hundred seventy-eight patients with TN allergy were
identified. One hundred one (36%) had a history of acute
reactions, 12 (12%) of whom had reactions to multiple tree nuts
and 73 (63%) of whom had a history of moderate-to-severe
reactions. Nine of 20 patients who had previously reacted to a TN
passed challenges, so that 9 (8.9%; 95% CI, 4% to 16%) of 101
patients with a history of prior tree nut reactions outgrew their
allergy. Fourteen of 19 who had never ingested TNs but had
detectable TN-specific IgE levels passed challenges. One hundred
sixty-one did not meet the challenge criteria, and 78 met the
criteria but declined challenges. Looking at specific TN-IgE
cutoffs, 58% with TN-IgE levels of 5 kU(A)/L or less and 63% with
TN-IgE levels of 2 kU(A)/L or less passed challenges.
- CONCLUSIONS: Approximately 9% of patients outgrow tree
nut allergy, including some who had prior severe reactions.
Although ideal cutoffs for challenge cannot be firmly
recommended on the basis of these data, patients aged 4 years
or older with all tree nut-IgE levels of 5 kU(A)/L or less
should be considered for challenge.' 255
(posted Nov 14th, 2005)
-In the Dec 2003 issue of Allergy, Rance F. et
al. are the authors of Cashew allergy: observations of 42
children without associated peanut allergy. The mean age at
diagnosis of cashew allergy was 2.7 years. One in five children
(12%) had a prior history of exposure to cashew nuts.
Clinically 56% had skin reactions, 25% respiratory, 17% digestive.
Eighteen children had associated food allergies: pistachio,
seven (same biological family as cashew nuts); egg, five; mustard,
three; shrimp, two, cow's milk, one.
- Conclusion: The increase in cashew allergy is worrying
because it affects young children who may have a reaction without
ever having been exposed to cashews..196
(posted Nov 22, 2003)
-According to the publication in the Oct 2005 Arch Dis
Child by Davoren M and Peake J. Cashew nut allergy is
associated with a high risk of anaphylaxis. The abstract reads:
Cashew allergy is an evolving clinical problem. A retrospective chart
review of 213 children with peanut or tree nut allergy was undertaken
over a 42 month period. Anaphylaxis to cashew nut was more common
than to peanut (74.1% v 30.5%). Children with cashew allergy are
at risk of anaphylaxis.251
(posted Sept 26th, 2005)
- Clark AT, Anagnostou K, Ewan PW published in Allergy. 2007 Aug;62(8):913-6, Cashew nut causes more severe reactions than peanut: case-matched comparison in 141 children.
Results: A total of 47 children in the cashew group were matched to 94 in the peanut group. There were no differences in clinical features between groups for matching criteria, except asthma (more prevalent in the peanut group). Wheezing and cardiovascular symptoms were reported more frequently during reactions in the cashew compared with the peanut group...
Conclusions: Previous studies show cashew nut can cause severe reactions; this is the first study to show by case-matching that severe clinical reactions occur more frequently in cashew compared with peanut allergy. The nut type which caused the worst reaction to date should be considered when providing emergency medication.274 (posted Aug. 3d, 2007)
re
macademia nuts :
-At the Annual AAAA&I meeting in San Diego, Mar 3-8th,
2000 RM Harris,MD reported on a case of macademia nut induced
anaphylaxis (macademia nut is an Australian tree nut, originating
from macademia intergrifolia, tetraphylla, and their hybrids).
Macademia nut oil is reportedly used as a dietary sutbstitute for its
health benefits. No testing extracts of macademia were available and
skin tests were done using fresh food. A 4+ positive result was
obtained not from the outer surface of the nut but from the pulp of
the nut. This is the first reported case of macademia nut
anaphylaxis, and it points out the need to consider "fresh food
testing" when prepared testing resources are not available. (posted
March 9th, 2000)102
- -At the same meeting, Sutherland M. et al, also reported on
anaphylaxis in an 18 year old female after eating a flourless
orange cake made with macademia meal. Skin test to raw
macademia nut was very positive (wheal of 30mm) one month later
and immunolgic immunoblot experiments showed the presence of a
protein related partly to hazelnut. The authors recommend that
macademia allergic patients should also avoid hazelnuts.
(posted March 9th, 2000).
- The author had previously published this report in Oct. 1999,
in the J Allergy Clin Immunol 1999;104:889-890, and had
found no cross-reactivity with peanut protein 103
(posted Dec 10th, 2000)
-In the Sept-Oct 2000 Allergy & Clinical Immunology
International , Falk et al report two cases of severe allergic
reactions following ingestion of macadamia nuts. The first
patient, a 48 year-old woman, had no other nut or peanut allergies
but did have a history of asthma and perennial allergic rhinitis,
related to cat dander, house dust mite, and grass pollen; she reacted
with oral allergy symptoms within minutes after eating 6-8 macadamia
nuts, and in 10 minutes developed palpitations, dyspnea, dizziness,
flushing and severe itch. Allergy tests showed a strong positive
reaction to macadamia nut, but nothing to other nuts and peanut. The
second case was a 34 year-old man, with a known allergy to tree nut
allergy, including hazelnut, who reacted within minutes after eating
one single macadamia nut, with tongue swelling, itchy hot palms,
swollen hands, and throat tightness, which resolved without specific
treatment. His skin tests revealed a strong allergy to hazelnut,
macadamia nut, and smaller, borderline, reactions to Brazil
nut and peanut.104 (posted Dec 21st, 2000)
-Another case of allergy to macadamia nuts was reported by
Pallares in the Nov. 2000 Annals of Allergy, Asthma and
Immunology. No mention of a link with peanut is mentioned,
and contrary to a link with hazelnuts mentioned by Sutherland in
their report posted above, this patient tolerated hazelnuts.123
(posted June 28th, 2001)
-In the Sept 2005 Pediatr Allergy Immunol , Clark AT
and Ewan PW have a publication entitled The development and
progression of allergy to multiple nuts at different ages. Seven
hundred and eighty four nut-allergic children, with evidence of
sensitization (presence of nut-specific IgE and positive skin prick
tests (SPT) to peanut, Brazil, almond, hazel and walnut were
prospectively enrolled. By 2 years of age at least 19% were
multi-sensitized, and 2% multi-allergic. Increasing proportions were
exposed to multiple nut types with increasing age (23% at 2 yr to 73%
by 10 yr) and greater proportions were multi-sensitized (19% at 2 yr
to 86% at 5-14 yr) and multi-allergic (2% at 2 yr to 47% at 14 yr).
This study is the first to define the natural history of multiple nut
allergies in childhood. New findings are that a large proportion
of those aged 0-1 yr with nut allergy are already sensitized (have
specific IgE) to multiple nut types, implying in utero or early life
sensitization; those who present later in childhood are increasingly
likely to be sensitized and clinically allergic to multiple nuts.
This is related to increased duration of allergy and exposure to
multiple nut types with age. Children with nut allergy should avoid
all nut types from the onset. 249
(posted Sept 25th, 2005)
re soy:
- -From Sweden, a survey on severe food allergies, published in
1999 by Foucard T, and Malmheden Yman I: A study on
severe food reactions in Sweden--is soy protein an underestimated
cause of food anaphylaxis? 68
The abstract reads as follows:
- "Because of a fatal case of soy anaphylaxis occurring in
Sweden in 1992, a study was started the following year in which
all physicians were asked to report fatal and life-threatening
reactions caused by food. The results of the first 3 years of the
study are reported here, including results from another ongoing
study on deaths from asthma during the same period.
- RESULTS: In 1993-6, 61 cases of severe reactions to food
were reported, five of them fatal. Peanut, soy, and tree nuts
seemed to have caused 45 of the 61 reactions, and four of them
were fatal. If two cases occurring less than a year before our
study started are included, we are aware of two deaths caused
by peanuts and four deaths caused by soy. All four
youngsters who died from soy anaphylaxis with asthma were
severely allergic to peanuts but had no previously known
allergy to soy. In most cases, there was a rather
symptom-free period for 30-90 min between early mild symptoms
and severe and rapidly deteriorating asthma.
CONCLUSIONS: Soy has probably been underestimated as
a cause of food anaphylaxis. Those at risk seem to be young people
with asthma and peanut allergy so severe that they notice symptoms
after indirect contact. " (posted May 13th, 1999)
-
- -In an article published in Revue Française
d'Allergologie et d'Immunologie Clinique, Vol. 43, no. 8,
2003, entitiled Allergie à l'arachide, la
cacahuète est-elle dangereuse?203
(Peanut allergy: are peanuts dangerous?) Bidat et al.
report a reaction that occurred in two children with an almost
identical history, aged 9 and 12 years,. They each have asthma
caused by environmental allergies, with a known peanut allergy,
one reacting also to peas, the other with a dislike of other
legumes, and both having a sensitivity to soy (not by skin
tests which were negative, but by elevalted soy-specific IgE
titres). Neither one has ever knowingly eaten or reacted to soy
products. They both had an anaphylactic reaction (asthma with
generalized urticaria) after eating lamb meat balls for lunch at
school. The lamb meat balls were later reported to have contained
a 27% mixture of "vegetable proteins derived from rehydrated
soy".
- Discussion: -In peanut allergic individuals, sensitization
to soy is frequent, (10-53%) but this sensitisation is manifested
clinically in only 2.3 to 11% of sensitized children. They
underline the risks of soy allergy and such accidents in peanut
allergic individuals reported in the Swedish study that is
summarized above.(posted Dec 15th, 2003)
-
Link
with lupine
-At the annual AAAA&I meeting held in San Diego, Mar
3-8,2000, Kanny reported on Acute asthma due to lupine
(lupinus albus, a legume) in a patient allergic to peanuts. The
patient has a severe allergy to peanuts, presenting as acute asthma.
Lupine flour is present in certain foods, authorized in France
in 1997. Skin tests to raw and cooked lupine flour were positive as
well as a high specific IgE titre to lupine flour. An oral challenge
test was also positive with 965 mg of lupine flour (this quantity is
present in 100 grams of bread.) Also published in Rev Med Interne
94.
(posted April 2nd, 2000)
-A search of Medline resulted in a few publications re the
association of lupine and peanut allergy:
-Hefle, Lemanske, and Bush reported an Adverse
reaction to lupine-fortified pasta in 1994 in a 5-year-old
girl with peanut allergy, in the form of urticaria and angioedema
after ingesting a spaghetti-like pasta fortified with sweet lupine
seed flour. The pasta was extracted and used in immunologic
studies in patients with peanut sensitivity to determine whether
such individuals are at similar risk. Skin prick tests done with
lupine pasta extract were positive in 5 of 7 peanut-allergic
subjects, also reporting adverse reactions to green peas; RAST
tests were also highly positive, and immunologic studies
corroborated this allergy in peanut sensitive individuals.
91
(posted Mar 12th, 2000)
-Toxicity to lupine was also reported.
- -In Oct 1999, in the J Allergy Clin Immunol,
Moneret-Vautrin et al studied the risk of cross-allergy
to lupine in patients allergic to peanut and lupine
allergenicity. Results: the skin prick test responses with
lupine flour were positive in 11 of 24 subjects (44%); challenges
positive in 7 of 8 subjects; the major lupine flour allergen (mol.
wt, 43kd) is present in peanuts.
- Conclusion: the risk of peanut-lupine allergy is high,
contrary to the risk with other legumes. The inclusion of 10%
lupine flour in wheat flour without mandatory labeling makes
lupine a hidden allergen, presenting a major risk of
cross-reaction in subjects already allergic to peanut products. A
high sensitizing potential can also be postulated for this
legume.92
(posted March 12th, 2000)
-In Nov 1999, a group from Spain (Matheu et al) published
in the Annals of Allergy, Asthma and Immunology, a case of
lupine-induced anaphylaxis. Skin tests and immunological
work-up showed a positive skin prick test to lupine and
cross-reactivity with other legumes, yet the patient tolerated a
peanut challenge as well a a green bean challenge, but not with
pea.The authors conclude that "discrepancies were found between
the clinical aspect and in vitro study of peanut allergy. Factors
determining the wide variability in cross-reactivity among
individuals are still obscure." 93(posted
March 11th, 2000)
-Occupational allergic symptoms were also reported after
exposure to lupine seed flour. 131
(posted Sept 3d, 2001)
-Monert-Vautrin in a discussion published in the Bull
Acad Natl Med 2001;185(5):943-57, again
brings up the lupine flour-peanut association, and the
increased use of lupine flour in baked goods.140
(posted Jan 14th, 2001)
- -In the July 2004 Int Arch Allergy Immunol.
Faeste et al have a publication entitled A Case of Peanut
Cross-Allergy to Lupine Flour in a Hot Dog Bread. In a case
monitored by the Norwegian National Register for Severe Allergic
Reactions to Food, a patient with peanut allergy experienced an
allergic reaction after eating a particular brand of hot dog
bread. Extracts from the hot dog bread and reference material from
peanut, lupine and lupine-fortified food products were analysed by
immunochemical methods with patient serum and a new polyclonal
anti-lupine antibody.
- Results: Evidence could be provided that the hot dog bread
contained proteins from lupine but not from peanut.
- Conclusion: Crossed peanut-lupine allergy can have
clinical significance. A peanut-allergic patient reacted
against hidden lupine protein in a hot dog bread. Presented
with our results, the producer confirmed the use of lupine
flour and changed the ingredient list. (posted Aug. 7th,
2004)231
-
- -Moreno-Ancillo et al have a publication in the Sept
2005 Pediatr Allergy Immunol entitled Lupine
inhalation induced asthma in a child. Here's part ot the
abstract:
- The ingestion of lupine seed flour has been reported as a
cause of allergic reactions. There is some evidence of its
allergenic potential after inhalation. An 8-year-old asthmatic
child, who was allergic to peanut, was studied in our clinic
because he suffered an asthma attack while playing with his
brother, who had been eating lupine seed as a
snack....The skin tests showed a positive result with
Lupinus albus extract, peanut, garbanzo bean, navy bean,
pea, green bean, lentil, soy, Olea europea pollen, grass pollen
and Plantago lanceolata pollen. The prick-by-prick tests
both from dried seeds and those preserved in salt and water
were strongly positive. Serum specific IgE antibodies
were positive to Lupine albus (1.43 kU/l), peanut (4.32
kU/l), soy (2.15 kU/l), lentil (3.12 kU/l) and garbanzo (0.7
kU/l). After informed consent, salbutamol was well tolerated
but the patient had asthma in 5 min of manipulation of the
lupine seeds. In our case, reactivity with other legumes
was also demonstrated, but only peanut allergy was relevant
because boiled legumes were tolerated. It is also notorious
that anamnesis is so important to assess the true etiological
agents of asthma.250
(posted Sept 26th, 2005)
- In the J Allergy Clin Immunol. 2007 Jul 14 Peeters KA et al published Lupine allergy: Not simply cross-reactivity with peanut or soy.
-
CONCLUSION: Lupine allergy can occur either separately or together with peanut allergy, as demonstrated by 3 patients who are cosensitized to peanut and lupine. CLINICAL IMPLICATIONS: Lupine flour is allergenic and potentially cross-reactive with peanut allergen, thus posing some risk if used as a replacement for soy flour. 273(posted Aug 3d, 2007)
-Wassenberg J, Hofer M in Ann Allergy Asthma Immunol. 2007 Jun;98(6):589-90, published Lupine-induced anaphylaxis in a child without known food allergy. The authors conclude ' To our knowledge, we describe the first case of an anaphylactic reaction after ingestion of lupine flour in a child without known allergy. In the case of peanut allergy or any anaphylactic reaction without evident cause, especially after industrially prepared food ingestion, lupine should be considered in the list of allergens tested. Lupine is increasingly used in industrially prepared food but is not regularly declared in the composition, leading to difficulties in allergen avoidance.' 275(posted Aug. 3d, 2007)
-In the J Dtsch Dermatol Ges. 2007 Sep;5(9):who 774-6, Brennecke S et al published Anaphylactic reaction to lupine flour. The authors report a case of a 52-year-old woman developed facial and mucosal edema, followed by dizziness and shortness of breath a few minutes after ingestion of a nut croissant containing lupine flour; she required emergency care. Allergy diagnostic tests revealed a total IgE of 116 kU/l, a highly elevated concentration of IgE specific for lupine seed (42.9 kU/l) and birch pollen IgE of 2.57 kU/l. Skin prick test with native lupine flour was strongly positive. Allergy against lupine seeds may develop de novo or via cross-reactivity to legumes, particularly peanuts, the latter being detectable in up to 88% of cases, founded on a strong sequence similarity between lupine and peanut allergens. In our patient, no cross-reactivity could be detected indicating a rare monovalent sensitization to lupine flour. Treatment consists of avoidance of lupine flour-containing products. Patients with proven peanut allergy should also avoid lupine flour because of the major risk of cross-reaction. (posted Oct 6th, 2007) 279
-
-
-
-
-
- What
about sesame seeds and oil?
-
-Birnaum and coll. presented a case of a 52 year old woman
having had hives on several occasions after eating
sesame seeds, Indian bread, Chinese, Greek or Indian meals in
restaurants, and facial swelling after local application of
creams which were found to contain sesame oil. She tested
positive to sesame on skin tests but not by RAST. (AAAA&I
Annual Meeting, 1997) (posted Feb 13th, 1999)
-Levy and coll. made a survey of sesame allergy in
Israel by doing RAST tests and skin tests on 234 patients
referred for food allergy evaluation during 1995-1996. RAST test
results: 13 (5.5%) were positive to sesame. Of patients referred
to a food allergy clinic with a history of angioedema, 15 of 61
were found to be skin test positive. Six patients from this group,
aged 14 months to 26 years, were open challenged with sesame. Five
were positive: urticaria (5), rhinitis/conjunctivitis (3), nausea
and tachycardia (1). (AAAA&I Annual Meeeting, 1998)
(posted Feb 13th, 1999)
-Sesame allergy, although less common than peanut allergy,
can be every bit as severe. Sesame is used extensively
in the food industry, and the seeds present a danger because of their
versatility 51.
With the increasing demand for vegetarian food, the consumption of
vegetable burgers as an alternative to beef burgers has now become
widespread
52.Sesame seed and sesame seed oil contain masked
allergens of growing importance 53and
a cause of occupational asthma54.
(posted Feb 13th, 1999)
- NB. There was no mention of sesame being related to
peanut in any of these papers, but:
- allergy to kiwi, poppy seeds, and/or sesame seeds often
occurs in patients with a simultaneous sensitization to nuts
and flour 45.
- A review of the database of results of allergen skin tests
by the dept of Allergy, Royal Children's Hospital, Melbourne,
Australia during 1990-96, sensitization to peanut was found
in 1601 infants and children, to a tree nut (almond, brazil,
cashew, hazelnut, or walnut) in 590; 491 to both: representing
a combined prevalence of sensitization of at least 0.2%.
Sensitization occurred early: 920 children aged under 24 months
were sensitized to peanut and 270 to a tree nut. But 531
children were found allergic to sesame seed, higher than
the number sensitized to any tree nut; sensitivity occurred in
60% of the children (317) before age 2. 55
(posted Feb 13th, 1999)
- A comment by Dr Rhoda Kagan, submitted in Oct. 1998.
when this article was started, was posted in the section on
'peanut oil'. It is now added to this section on sesame:
- Sesame oil, derived from sesame (which is not
a nut) used frequently, will often contain
considerable amounts of peanut proteins.
-
- -In the Nov 24th, 2001 The Pharmaceutical
Journal, vol. 267, Maggie Spirito Perkins has an article
entitled, Raising
Awareness of Sesame Allergy, where she states....'it is not
uncommon for sesame allergy to co-exist with peanut allergy.'
(posted Nov 20th, 2002)
- -In the Aug 2003 Pediatr Allergy Immunol, Binson
et al published The pattern of sesame sensitivity among infants
and children. ...although the main clinical
manifestation was urticaria/angioedema, anaphylaxis was the
presenting symptom in 30% of cases, all of them younger than one
year. 70% were found to be allergic to other foods, and other
atopic diseases were identified in 78%. These patients outgrew
their allergy within 1-2 years....Early exposure may cause sesame
to share eventually the same 'noteriety and fate' as peanut .
No mention is made of a relationship between sesame and peanut.
189
(posted Aug 15th, 2003)
-
-In the Ann Allergy Asthma Immunol. 2006 Oct;97(4):443-5, Beausoleil, JL, and Spergel JM have a publication entitled 'Late diagnosis of tree nut and sesame allergy in patients previously sensitized but tolerant to peanut.' Quoted from their abstract:
Recent studies have indicated that tolerance to peanut can occur in patients with a history of peanut allergy. Tree nut and sesame allergies have been reported to occur at increased incidence in patients with peanut allergy. Although the coexistence may be simply due to a predisposition to food allergy in these individuals, cross-reactivity has been demonstrated between peanut and tree nuts and between peanut and sesame seed. OBJECTIVE: To describe 3 patients previously sensitized but tolerant to peanut who were subsequently diagnosed as having either tree nut or sesame allergy. METHODS: All the patients had a clinical history of peanut sensitivity and underwent follow-up peanut skin testing to commercial extracts using a bifurcated needle followed by a graded peanut challenge. One patient had a previous positive radioallergosorbent test reaction to sesame and underwent a graded sesame challenge. RESULTS: All the patients had negative peanut challenge results. Two patients subsequently had exposure to tree nuts at home and had systemic reactions and positive skin test reactions to the incriminated tree nut. One patient had a positive challenge reaction to sesame. CONCLUSION: Demonstration of tolerance to peanut may falsely reassure patients and physicians that patients no longer need to avoid tree nuts or sesame. Tree nut and sesame allergies can exist or develop in patients despite the development of tolerance to peanut. (posted Nov 1st, 2006)
-
-
-
- What
about sunflower seeds and oil?
- -Sunflower seeds have been reported causing severe allergic
reactions in sensitive individuals48
Sunflower oil is not allergenic to sunflower seed-sensitive
patients 49.
- -Hefle et al at the AAAA&I Annual Meeting in 1997
presented a paper about their experience in the identification and
characterization of sunflower seed allergens: scant knowledge so
far. Relationship of sunflower pollen and other pollens of the
Compositae family, including short ragweed50(posted
Feb 13th, 1999)
-
- What about
coconut?
-
- -In the June 1999 J Allergy Clini Immunol,
issue, Teuber et Peterson report a "Systemic allergic reaction
to coconut (Cocos nucifera) in 2 subjects with hypersensitivity to
tree nut and demonstration of cross-reactivity to legumin-like
seed storage proteins: new coconut and walnut food allergens.". .
. The reduced coconut protein. . . was previously shown to be
immunologically similar to soy glycinin.They conclude that
coconut allergy in patients with tree nut allergy is rare;
these are the first two patients ever reported, and therefore
there is no general indication to advise patients eith tree nut
allergy to avoid coconuts. 70.
(posted June 14th, 1999))
-
-
Identification
of the allergenic peanut proteins
-
- -According to Clarke and coll., in the Oct. 1998
Clinical Experimental Allergy, there are 19 peanut
proteins. . . the major ones being Ara h 1 and Ara h 2 to
which 70% of subjects reacted. Their study, however, highlights
the diversity of the peanut allergens, and because the
percentage of cases with sensitivity to a 15kDa protein was
found to be higher in patient groups with severe reactions to
peanut, they conclude that diagnostic extracts containing a
high proportion of this 15kDa component may aid in
diagnosis39.
-
- -". . . following our characterization of the two peanut
allergens Ara h 1 and Ara h 2, we have isolated a cDNA clone
encoding a third peanut allergen, Ara h 3. . . recognized . . .by
serum IgE from approximately 45% of our peanut-allergic patient
population . . . " 57
(posted March 12th,
1999)
-
- -Kleber-Janke, and coll. report in
Int Arch Allergy Immunol Aug 1999, that sera of 40
peanut-allergic individuals detected at least one of six
identified recombinant allergens which can be used to
establish individual patients' reactivity profiles. A comparison
of these profiles with the clinical data will possibly allow a
further insight into the relationship between clinical severity
of the symptoms and specific IgE levels toward the six peanut
allergens. 82
(posted Sept 6th, 1999)
- -In the Apr 2004 Clin Exp
Allergy, Koppelman SJ et al have a publication entitled
Relevance of Ara h1, Ara h2 and Ara h3 in peanut-allergic
patients, as determined by immunoglobulin E Western blotting,
basophil-histamine release and intracutaneaous testing: Ara h2 is
the most important peanut allergen....'previously identified
peanut proteins with molecular weights of somewhat smaller than 15
kDa may be important allergens as well....'215
(posted April 10th, 2004)
-Current developments in peanut allergy is the title of a pulication in the June 2006 Curr Opin Allergy Clin Immunol. by Palmer K, Burks W. Citing the abstract, 'Peanut sensitization may be both a Th1- and Th2-driven process, and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) may play a role in regulating the response intensity. Preliminary work shows that the food matrix is important in the immune response to peanut and that purified peanut allergens may have little intrinsic stimulatory capacity. Studies characterizing peanut allergens have revealed Ara h 1 and Ara h 2 as the most potent allergens, but Ara h 3 may be more allergenic than previously thought. There appears to be a relationship between the diversity of IgE-binding patterns and the severity of clinical symptoms. 259 (posted May 26th, 2006)
- In Clin Exp Allergy. 2007 Jan, Peeters et al published 'Does skin prick test reactivity to purified allergens correlate with clinical severity of peanut allergy?'The authors concluded: Ara h 2 and Ara h 6 appeared to be more potent than Ara h 1 and Ara h 3. Both SPT reactivity to low concentrations of Ara h 2 and Ara h 6 and to higher concentrations of Ara h 1 and Ara h 3 were shown to be indicative of severe symptoms. (posted May 26th, 2007)
- In Clin Exp Allergy. 2007 Aug;37(8):1221-8, Flinterman AE et al in their study concluded that Children with peanut allergy recognize predominantly Ara h2 and Ara h6, which remains stable over time. 272 (posted Aug 3d, 2007)
-
-
Effect of roasting on peanuts
-
- -According to a study reported in the
Oct. 2000 J Allergy Clin Immunol, thermal
processing such as roasting, may play a part in enhancing the
allergenic properties of peanuts. 99
(posted Oct. 29th,
2000)
-
- -In the June 2001 J Allergy
Clin Immuno, Beyer et al reported on the "Effects of
cooking methods on peanut allergenicity". Their concluson is
that the methods of frying and boiling peanuts, as practiced in
China, appear to reduce the allergenicity of peanuts compared
with the method of dry roasting practiced widely in the United
States. Roasting uses higher temperatures that appararently
increase the allergenic properties of peanut proteins and may
help explain the difference in prevalence of peanut allergy
observed in the the two countries. 120(posted
June 10th, 2001)
-
- -Because of the serology of peanut
allergy seeming to be different in vaious parts of the world, a
study from The Netherlands showed that peanuts of different
varieties contain similar proteins, including Ara h 1 and Ara h
2. 113
(posted Feb. 15th, 2001)
- -See
CBS news 'Cracking a peanut's deadly secrets' and video on
research being done on some 14,000 different types of
peanuts. (posted Dec 4th,
2002)
-
- -Maleki et al in the July
2003 J Allergy Clin Immunol have an article entitled
The major peanut allergen, Ara h 2,
- functions as a trypsin inhibitor, and roasting enhances
this function.
- Results: Ara h 2 purified from peanuts is
homologous to and functions as a trypsin inhibitor.
Roasting caused a 3.6-fold increase in trypsin inhibitory
activity. Functional and structural comparison of the Ara h
2 purified from roasted peanuts to native and reduced Ara h 2
from raw peanuts revealed that the roasted Ara h 2 mimics the
behavior of native Ara h 2 in a partially reduced form.
- Conclusions: The data indicate that thermal processing
might play an important role in enhancing the allergenic
properties of peanuts. Not only has it previously been
shown to affect the structural and allergic properties of
peanut proteins but also, for the first time, the functional
characteristics of an allergen. These structural and
functional alterations are likely to influence the
allergenicity of peanuts.181
(posted July 12th, 2003)
- -Maleki et al. have another publication in the July
2003 J Agric Food Chem: Linking peanut allergeniciy
to the processes of maturation, curing, and roasting. Besides
roasting (as reported above) that seems to have an effect on
allergenicity, Other processes (maturation and curing) were
evaluated.
Results showed that mature roasted peanuts exhibited a higher
IgE binding and advanced glycation end adducts (or AGEs) than
immature roasted peanuts.... so did curing at higher
temperatures.187
(posted Aug 3d, 2003)
-
- -In the Revue française d'allergologie et
d'immunologie clinique 2003 - Volume 43 - Numéro
8 - pp: 486-491, Mondoulet et al. have an article entitled
Influence des procédés thermiques sur
l'allergénicité de l'arachide (Influence of thermal
processing on the IgE binding capacity of peanut allergens).
The authors found that roasting peanuts does not modify
their allergenicity while boiling decreases it considerably.
This decrease of boiled peanut allergenicity comes from a loss of
some allergens into the boiling water. It may also be due to
structural modifications of peanut proteins that occur in boiling
water. 201
(posted Dec. 14th, 2003)
-
- -At the Annual AAAA&I meeting held in San Francisco,
Mar 19-23, 2004, Maleki et al had a poster entitled
Roasting may alter the IgE binding epitopes and sensitizing
ability of peanut allergens. Their results indicate that many
of the IgE binding, digestion resistant fragments are modified
with sugar by-products that occur as a result of roasting. Also,
in some occasions roasting alters the IgE-binding fragments that
survive digestion, and therefore, quite possibly, the allergenic
epitopes. These altered epitopes may be responsible for in vivo
data that demonstrate mice are more likely to be sensitized to
roasted than raw peanuts.220
(posted April 28th, 2004)
- -In the July 2004 J Agric Food Chem. Chung SY,
Maleki SJ, Champagne ET. have a publication called Allergenic
properties of roasted peanut allergens may be reduced by
peroxidase. The authors have shown that a significant decrease
was seen in the levels of the major allergens, Ara h 1 and Ara h
2, in roasted peanuts after peroxidase treatment...helping to
reduce the allergenic properties of roasted peanut
allergens.230
(posted July 20th, 2004)
- -Kopper et al published Peanut protein allergens: the
effect of roasting on solubility and allergenicity in the
Jan 2005 Int Arch Alleergy Immunol:
"Progressive roasting of peanuts results in a significant
decrease in protein solubility...The presence of these
insolubilized proteins provides a continuous source of major
allergens to the gastrointestinal mucosal immune system." (posted
April 22nd, 2005)243
Immunotherapy
(hyposensitization or desensitization)
-The question of desensitization (immunotherapy) has been brought
up many times because of the increasing problem of peanut allergy, to
try and help the patients diminish their allergy to peanuts, one
reason being the large number of accidental ingestions. Over the
years, trials have been published, the last one by Nelson, Bock et
al, in June 1997. They recruited 12 patients with immediate
hypersensitivity to ingestion of peanuts. Half were treated with
injections of peanut extract: a maintenance level of tolerance was
first achieved by a rush protocol, then maintained with weekly
injections for at least a year. The other six were untreated control
subjects. All patients underwent double-blind, placebo-controlled,
oral peanut challenges initially, after approximately 6 weeks, and
after 1 year. Only three patients remained tolerant of the full
maintenance dose. The increased tolerance to oral peanut challenge
was maintained in the three subjects who received full maintenance
doses, but there was partial or complete loss of protection in the
patients who required dose reduction because of systemic reactions
(allergic symptoms following desensitization injections). The
authors conclude that injections of peanut extract increase the
tolerance of patients with peanut allergy to oral ingestion of
peanuts. Injections result in repeated systemic reactions in most
patients, even during maintenance injections. For clinical
application of this method of treatment, a modified peanut extract is
needed3.
In summary: at this point in time, desensitization for
peanut allergy, although promising, is not recommended because of
the dangers involved during treatment in the form of severe
reactions. More research is needed before such treatment can be
considered.
- -In a communication in the Nov
1998 issue of the Canadian Journal of Allergy &
Clinical Immunology, Dr. Joseph Greenbaum recounts his
experience with food immunotherapy, including one case of
peanut immunotherapy. Although the author was encouraged with
the results, the editor of the journal, Dr. Gordon Sussman,
warns in his note, that "although well tolerated and appearing
efficacious in this report, several pitfalls and possible
dangers of this type of treatment need to be addressed...It
is impossible to assess efficacy without a control
population...The major concern is patient safety. Food
immunotherapy may be an extremely dangerous procedure and
can create a false sense of security. Several severe
reactions and deaths have been reported using food
immunotherapy, even in well-designed studies. Food
immunotherapy, as outlined in these case studies sets a
dangerous precedent which could have disastrous
consequences. We agree that the treatment of food
anaphylaxis using avoidance is not ideal -- but it is
presently the only proven treatment we have. Let's work
together to develop a better treatment through properly
designed research protocols that give us reliable and
reproducible information."
40.
(posted Dec 8th, 1998)
-
-
- -"Scientists develop vaccine strategy for peanut allergy"
is a commentary by Scott Gottlieb, from New York, published in
the April 3d, 1999 British Medical Journal 60,
referring to the work of Dr Kam Leong, and associates at the Johns
Hopkins School of Medicine in Baltimore, reported in Nature
Medicine 66
"Researchers believe that they may be close to developing a new
strategy to combat anaphylactic allergies - such as the
increasingly common allergy to peanuts- in which doctors induce
tolerance using an oral formulation containing a gene from the
offending allergen. . .the DNA from peanut was administered orally
to mice. . . the severity of anaphylaxis was blunted. . .the
findings are a long way from being used in clinical
applications." . . "The immune system of mice is also quite
different from that of man. . . One can envision that this model
would be an interesting approach to generate mucosal immunity for
a variety of allergens" said Dr Leong. (posted April 5th and 18th,
1999)
-
- To see an example how such research could be interpreted
differently:
- BBC
News on line, April 1st, 1999
- Also, relevant news stories:
- Food
producers play safe with nuts(20 Jul 98 | Health .
- Food
allergy clinic opens for mums-to-be (29 Jun 98 |
Health.
- Women
can 'pass peanut allergy to their children' (01 Apr 99 |
Health.
- (posted April 6th, 1999)
-
-In the Aug. 1999 J Allergy Clin Immunol, Hong,
Michael, Fehringer and Leung report on their experience with a
pepsin-digested peanut extract that could eventually be
used in desensitization. Previous immunotherapy (desensitization)
studies of peanut-allergic patients (one of which is summarized
above) showed a high incidence of systemic allergic reactions during
treatment, making such treatment very dangerous, and not practical at
this point in time. Researchers are constantly looking for a modified
peanut extract to lower allergenic properties (in other words,
resulting in much less systemic reactions.) Laboratory evaluation of
this extract suggests that it may be useful in peanut immunotherapy
because "pepsin digestion eliminates IgE reactivity but maintains
T-cell reactivity" (less systemic reactions yet still
effective)81
(posted Aug 23d, 1999)
-Bannon et al, in their Jan 2001 article
in Int Arch Allergy Immunol: entitled Engineering,
Characterization and in vitro Efficacy of the Major Peanut Allergns
for Use in Immunotherapy, report their results with modification
of the peanut proteins and conclude that ..."These modified genes
and proteins should provide a safe immunotherapeutic agent for the
treatment of peanut allergy.".119
- Wild LG and Lehrer SB, in the Jan 2001 Curr Allergy
Rep, (posted in Medline only in April 2002,!?) summarize the
ongoing research on desensitization in food allergy in their artilcle
Immunotherapy for food allergy. "With better characterization
of allergens and better understanding of the immunologic mechanism,
investigators have developed several therapeutic modalities that
potentially are applicable to the treatment and prevention of food
allergy. Therapeutic options currently under investigation include
peptide immunotherapy, DNA immunization, immunization with
immunostimulatory sequences, anti-IgE therapy, and genetic
modification of foods. These exciting developments hold promise
for the safe and effective treatment and prevention of food allergy
in the next several years."153
(posted April 29th, 2002)
-See:
Effect of Anti-IgE Therapy in Patients with Peanut Allergy.
(discussed below in the section on "Recent studies" posted Mar
28th, 2003.
-From the San José Mercury News, in
the Nov 2004 on line edition of Allergy, lead
researcher Dale T. Umertsu describes its canine vaccines, the first
to block food allergens in an animal larger and more complex than a
mouse...Researchers manipulated the immune system of the dogs to
mimic a human allergic response. Before being vaccinated, the dogs
could barely eat one peanut before breaking out in a skin rash. But
10 weeks after immunization, the animals devoured, on average, more
than 37 peanuts before developing symptoms....This vaccine could
one day enable millions of food allergy sufferers to fearlessly bite
into a peanut butter sandwich. The study appears in the Feb
2005 Allergy entitlled, Allergen immunotherapy with
heat-killed Listeria monocytogenes alleviates peanut and food-induced
anaphylaxis in dogs. Heat-killed Listeria monocytogenes (HKL)
potently stimulates interferon (IFN)-gamma production in CD4
T-lymphocytes, and when used as adjuvant for immunotherapy, reduces
immunoglobulin (Ig)E production and reverses established
allergen-induced airway hyperreactivity (AHR) in a murine model of
asthma. We asked if such treatment could decrease established
peanut-induced anaphylaxis.. in highly food-allergic dogs.The dogs
were then vaccinated once subcutaneously with peanut or milk and
wheat with HKL emulsified in incomplete Freund's adjuvant.
Conclusions: Thus, HKL plus allergen treatment
markedly improved established food allergic responses in dogs,
suggesting that such an immunotherapy strategy in humans might
greatly improve individuals with food allergy and
anaphylaxis.240
(posted Jan 15th, 2005)
-Dr Wesley Burks, chief of the division of
Pediatric Allergy and Immunology at Duke University Medical Center,
is working on desensitization (similar to the above Nov. 1998 report,
by Dr J. Greenbaum, commented by Dr Sussman) by progressively
administering increasing quantities of peanut protein (2005).
See Fighting
Food Allergies.
(includes audio) (posted April 30th,
2005).
-More on Dr Wesley Burks's encouraging study : Can Deadly Peanut Allergies Be Cured ? (ABC News, including a video) June 23d, 2006) (posted June 26th, 2006)
-At the annual AAAA&I meeting held in San Diego,CA in Feb 2007, Dr Burks' group presented Oral Peanut Immunotherapy for Peanut Allergic Patients. It's presumably a report of the work posted above in 2005. The study included children with a convincing history of peanut allergy and an IgE >7kU/L . The study protocol was divided into three phases: a modified rush initial day of multiple doses (0.1 mg to 50mg peanut doses), a build up phase of daily doses, increasing the dose every 2 weeks, and a daily maintenance phase of up to 18 months (dose of 300 mg peanut protein). An open food challenge to peanut flour (7.8 gms) was performed at the end of the study...Eight children completed the initial protocol and have undergone an open food challenge. Seven tolerated the maximum dose in the challenge. One subject had mild allergic symptoms treated with antihistamines after 4.2 gms of peanut flour. During the modified rush phase most subjects had mild symptoms but some subjects had more significant, systemic allergic symptoms. Adverse events related to the build up or maintenance phases were minimal. The initial mean peanut-specific IgE was 62.64kU/L with a significant decrease at 24 months to 21.92 kU/L. The authors conclude: ...peanut oral immunotherapy is safe and effective for decreasing the risk of a significant reaction with peanut ingestion... and a peanut-specific IgE level decrease. (posted May 6th, 2007)
- -In
the Nov 2005 J Allergy Clin Immunol, Enrique E et al have a
publication entitled Sublingual immunotherapy for hazelnut food
allergy: a randomized, double-blind, placebo-controlled study with
a standardized hazelnut extract. Efficacy was assessed...after
8-12 weeks of treatment.
- Results: Systemic reactions were
observed in only 0.2% of the total doses administered. Mean
hazelnut quantity provoking symptoms increased from 2.29 g to
11.56 g in the active group versus 3.49 g to 4.14 g in the placebo
group. Moreover, almost 50% of patients who underwent active
treatment reached the highest dose (20g), but only 9% in the
placebo.
- Conclusion: Our data confirm
significant increases in tolerance to hazelnut after
sublingual immunotherapy....258
(posted May 7th,
2006)
-In the Dec 2005 Curr Opin Allregy Clin Immunol,
Pons, Palmer and Burks published Towards immunotherapy for peanut
allergy.
Taken from the abstract: Based on extensive
characterization of food allergens and a better understanding of
the immunological mechanisms underlying allergic disease,
promising therapeutic modalities for food allergy treatment and
prevention are being developed. RECENT FINDINGS: Immunotherapeutic
strategies include peptide immunotherapy, mutated protein
immunotherapy and DNA immunization, which all strive to decrease
the deleterious Th2 response. Another approach already in clinical
trials for peanut allergy is the anti-IgE therapy which prevents
circulating IgE from binding to effector cells, consequently
decreasing clinical symptoms after peanut ingestion. In order to
be applicable, these strategies must be well tolerated,
inexpensive and easily administered. Realistic treatment options
would likely involve a combination of different
approaches.254
(posted Nov 11th, 2005)
Dealing with peanut
allergy:
position
statements.
-
- More on
anaphylaxis:
- Anaphylaxis
- Dr. Peter Vadas of the University of
Toronto has been comparing blood samples from people who had
mild peanut reactions to samples from people who died from the
allergy. He has found, he said, that those who died had low
levels of an enzyme that breaks down chemicals that contribute to
the severity of a reaction.In the short run, Vadas said,
measuring levels of the enzyme ''can help stratify people, to
point to those most at risk for having severe reactions.''
Those people would know they needed to take extreme precautions,
he said, and others with the allergy could be liberated from the
constant worry that a sudden reaction could kill them.What's more,
he said, if patients' levels of the enzyme can be increased,
that could, theoretically, protect them from fatal reactions.
(posted Oct 7th, 2002)
- Platelet-Activating Factor, PAF Acetylhydrolase, and Severe Anaphylaxis is the title of a publication in the NEJM Jan 3, 2008. Methods: They measured serum PAF (platelet activating factor) levels and PAF acetylhydrolase activity in 41 patients with anaphylaxis and in 23 control patients. Serum PAF acetylhydrolase activity was also measured in 9 patients with peanut allergy who had fatal anaphylaxis and compared with that in 26 nonallergic pediatric control patients, 49 nonallergic adult control patients, 63 children with mild peanut allergy, 24 patients with nonfatal anaphylaxis, 10 children who died of nonanaphylactic causes, 15 children with life-threatening asthma, and 19 children with non–life-threatening asthma.
Results: serum PAF levels were significantly higher in patients with anaphylaxis than in patients in the control groups and were correlated with the severity of anaphylaxis. The proportion of subjects with elevated PAF levels increased from 4% in the control groups to 20% in the group with grade 1 anaphylaxis, 71% in the group with grade 2 anaphylaxis, and 100% in the group with grade 3 anaphylaxis (P<0.001). There was an inverse correlation between PAF levels and PAF acetylhydrolase activity (P<0.001). The proportion of patients with low PAF acetylhydrolase values increased with the severity of anaphylaxis (P<0.001 for all comparisons). Serum PAF acetylhydrolase activity was significantly lower in patients with fatal peanut anaphylaxis than in control patients (P values <0.001 for all comparisons).
Conclusions: Serum PAF levels were directly correlated and serum PAF acetylhydrolase activity was inversely correlated with the severity of anaphylaxis. PAF acetylhydrolase activity was significantly lower in patients with fatal anaphylactic reactions to peanuts than in patients in any of the control groups. Failure of PAF acetylhydrolase to inactivate PAF may contribute to the severity of anaphylaxis. These data provide the rationale for the development of drugs to selectively block the actions of PAF, both as rescue therapy in cases of acute anaphylaxis and potentially as long-term preventive treatment for those at highest risk for fatal anaphylaxis. Demonstration of the efficacy of such agents would serve to ensure that PAF is a link in the chain of causality between allergic events and the anaphylactic phenotype. Although these data show that elevated levels of PAF and decreased PAF acetylhydrolase activity correlate with anaphylaxis, further studies will be required to assess the usefulness of PAF acetylhydrolase as a biochemical marker to identify patients at highest risk for fatal anaphylaxis, so that appropriate risk-reduction strategies20 can be implemented. 282(posted Jan 3d, 2008)
-Editorial by Dr A.Wesley Burks in the same issue of the NEJM, Jan 3, 2008: Factoring PAF in anaphylaxis.
The results could have long-term implications in the development of biomarker assays for diagnosing the occurrence and risk of anaphylaxis. Currently, the diagnosis of anaphylaxis is based primarily on clinical history and supporting laboratory tests. Patients can have hives, itching, flushing, swelling, difficulty breathing, hypotension, or gastrointestinal symptoms. Anaphylaxis can be difficult to recognize because, although the majority of cases involve skin symptoms, not all do, especially those in patients with life-threatening symptoms, and patients can have diverse symptoms between episodes. Anaphylaxis is also difficult to recognize if it is triggered by a new agent, is a person's first episode, or occurs in an uncommunicative patient, such as an infant. Symptoms can also be resolving or masked by medications by the time patients present for treatment. Standardized risk assessment for reactions does not exist, and patients with confirmed sensitivities to certain triggers are counseled to avoid them and to treat themselves with epinephrine should an exposure occur. Sensitive and specific biomarkers of anaphylaxis and evolving anaphylaxis could be used to establish the presence of the disorder or the likelihood of its future occurrence. In addition to PAF, mast-cell mediators that have been correlated with anaphylaxis and could be included in a biomarker panel include histamine, tryptase, chymase, and mast-cell carboxypeptidase A3.Finding additional biomarkers of disease and developing genetic testing for the prediction of disease, its severity, and the response to treatment should be a priority. With further understanding of the mechanisms involved in anaphylaxis, we can hope that some certainty can be provided toward managing such an uncertain condition. (posted Jan 3d, 2008)
- Jeffrey Linzer, MD , Pediatrics,
Anaphylaxis
- In the Sept 2002 J Allergy
Clin Immunol Anaphylaxis:
A review of causes and
mechanisms,
Kemp SF and Lockey RF, write re
incidence of anaphylaxis:
- "overall, approximately 154 annual
fatal episodes per 1,000,000 hospitalized subjects occur
internationally. (Epidemiology 1998;9:141-6)
- The estimated risk of anaphylaxis
per person in the United States is 1% to 3%.
87
- An estimated 150 fatalities from
food-induced anaphylaxis occur each year in the United
States80;
peanuts and tree nuts accounted for 30 (94%) of 32 fatal cases
voluntarily reported to a national registry for fatal
anaphylaxis."110
- Re peanuts, they further
state...Anaphylaxis to peanuts and tree nuts is of
special concern because of its life-threatening potential,
especially in subjects with asthma, and the propensity
for life-long sensitivity to these foods. Investigators have
reported that the majority (52%) of children with peanut
allergy experience life-threatening symptoms with subsequent
reactions, even when atopic dermatitis previously has been
the only adverse clinical manifesation105
(posted Nov 13h, 2002)
- Epineprhine
dispensing patterns for an out-of-hospital population: A novel
approach to studying the epidemiology of anaphylaxis.is
the title of an article in the Oct 2002 J Allergy Clin
Immunol by Simons FER, Peterson S, and Black CD.
- -The true rate of occurrence of anaphylaxis from all
triggers (foods, latex rubber, insect venoms, et
medications) is unknown, according to the authors....'not
as rare as is generally believed and that more than 1% of
the US population might be affected...uncommon but
increasing.'
- -The object of the study was to obtain a perspective on
the epidemiology of anaphylaxis in a defined general
population by studying epinephrine dispensing patterns.
These are their findings:
- -During the five-year period, 0.95% of this
defined general population had injectable epinephrine
dispensed for out-of-hospital treatment.
- -There were substantial variations in epinephrine
dispensing rates across subsets of the population,
ranging from 1.44% for individuals younger than 17
years of age, to 0.9% for individuals 17 to 64 years of
age (inclusive), to 0.32% for those age 65 years or
older.
- -In infancy, childhood, and early adolescence boys
were more likely to have epinephrine dispensed than
girls.
- -Beginning at age 15 years and continuing into
adulthood, girls and women were more likely to have
epinephrine dispensed than boys and men.
- -In the elderly there were no differences in
dispensing patterns between the sexes.
- -The highest epinephrine dispensing rate (5.3%)
was found for boys age 12 to 17 months.
- Conclusions: Epinephrine dispensing data provide a
novel and practical approach for studying and monitoring the
epidemiology of anaphylaxis in a community. Using this
approach, we provide evidence that anaphylaxis from all
triggers peaks in early childhood and then gradually
declines into old age. 162
(posted Nov 13th, 2002)
-
- Demographics of Children Dispensed Injectable Epinephrine
in Three Massachusetts School Districts is the title of an
oral presentation at the American College of Allergy, Asthma and
Immunology held in Boston Nov 12-17,2004, by P. J.
Hannaway.
- Methods: School nurses in 44 schools (grades PK-12)
enrolling 21,870 students recorded the characteristics of
students prescribed injectable epinephrine including the number
and racial mix of students in each school, student age, grade
level, race, sex, and allergic disorder requiring epinephrine.
Surveyed school districts were two predominately white (98%)
suburban districts enrolling 5,855 students and one urban area
with a minority population of 60% enrolling 16,020 students.
The use of epinephrine for peanut allergy was analyzed in
detail.
- Results: A total of 181 of 21,875 (0.83%)
students in three school systems were dispensed injectable
epinephrine. Males outnumbered females (110 to 71). Whites
outnumbered non-whites 153 to 28. Two thirds (n=116) of
children dispensed epinephrine had peanut allergy. The
second most common allergy was stinging insect allergy
(n=34). The rate of dispensed epinephrine for peanut allergy
was lowest in the urban school district (0.30%) versus the
two suburban districts, 1.1% and 1.26% respectively. Whites
with peanut allergy outnumbered non-whites 99 to 19. Males
outnumbered females 69 to 49. The lowest rate of prescribed
injectable epinephrine for peanut allergy in all three
school districts was found in 9,612 non-white school
children-0.17%. Eighty-nine of 118 (75%) school children
with peanut allergy were enrolled in grades PK through 5.
There were twice as many white versus non-white (32 to 16)
school children in the urban system with prescribed
injectable epinephrine for peanut allergy. Only eight (.11%)
of 7,209 Hispanic and Asian students in the study were
dispensed injectable epinephrine for peanut allergy.
Conclusions: This is the first study to suggest that
there may be a racial disparity in the prevalence of
childhood peanut allergy. One possible explanation for this
disparity is that varied feeding practices in minority infants
and children may induce a state of tolerance and lead to a
lower incidence of peanut allergy. (posted Dec 15th,
2004)
- EpiPen epidemic: Suggestions for rational prescribing in
childhood food allergy is the title of a publication by Kemp A
from New South Wales, Australia, in the July 2003 J
Paediatr Child Health.
- The abstract reads as follows: "There has been a marked
increase in community concerns of the risk of food induced
anaphylaxis in children and a consequent increase in the
provision of the self or carer injectible epinephrine
(EpiPen). The Australian use of EpiPens in children under
10 years has increased by 300% over 5 years with a crude
rate of EpiPen provision of 1 per 544 Australian children
aged under 10 years. However, the risk of a fatal
reaction to food, particularly in preschool children, is
remote (in Australia, an estimated one fatality in 30 years
in the under 5-year-old population and 2 deaths in 10 years
in the entire child population). It is therefore
important to provide a perspective on the risk of death
from food induced anaphylaxis to parents and carers in view
of the anxiety generated on this issue. The indications
for provision of an EpiPen to childre are not well
defined.
- Six risk factors, which can be considered in
evaluating the risk of a life-threatening reaction
:
- 1. Age over 5 years
- 2. A history of respiratory tract involvement with the initial or subsequent reactions
3. A history of asthma requiring preventer medication
4. Peanut or tree nut sensitivity
5. Reactions induced by trace or small amounts of
allergen
6. A strongly positive skin prick test.
- It is suggested that the greater the number that are
positive, the lower the threshold for provision of an
EpiPen."188
(posted Aug 4th, 2003)
- In May 2001, there appeared in the Archives of
Disease of Childhood, a publication entitled, Adrenaline
syringes are vastly over prescribed, (complete
article accessible) by D J Unsworth. In his introduction he
states, "Death following anaphylaxis is most feared but
fortunately remains a very rare event, currently estimated at
less than one case per year per million of the UK population." ...More than 100,000 adrenaline syringes are currently available
in the community in the UK, many in the paediatreic
context....Inappropriate use is to be avoided...It seems
reasonable to prescribe adrenaline in cases where there has been a
previous life-threatening allergic reaction".204
(posted Dec 17th, 2003)
- Obviously, there were many
responses to this publication (all, by the
way, accessible) by Toni Wolff, Jonathan
Hourihane, June Abay, Pamela Ewan, et
al ). Here are some highlights:
- Wolff: We are sure we are not the only
community paediatric team who have similar concerns...We
have more experience of the practial problems...Children
having adrenaline devices can still be excluded from
certain activities...Devices at times lost on the bus, or
accidentally fired, or out of date....Often parents or
children not instructed in their use.
- Hourihane: The article is not a balanced
review of the current state of allergy
practice...Adrenaline is not the only help given in
clinic to families with an allergic child. It is part of
an integrated management plan, which appears to be
effective, though difficult to measure...Every child
has the right to best available care...Anaphylaxis is
a critical situation in which prompt administration of
epinephrine may save a life...Doctors must remember
epinephrine is prescribed to be available for response
to infrequent exposure at an uncerain future
date....The provision of epinephrine kits allows
normal life to go on...
- Abay: Unexpected exposures are
inevitable...and appropriate prescription of
epinephrine remains the best available
treatment...Any person at risk of anaphylaxis
deserves the best available protection...
- Ewan: Most of the reasons he gives and the
papers he quotes consider provision of epinephrine
autoinjector in isolation and fail to recognise that children with food allergy need a complete management
package... Intramuscular epinephrine is very
safe...Accute diagnosis is essential as well as an
assessment of the severity of the allergy. (posted Dec
26th, 2003)
-
- In the Dec 6, 2003 BMJ (British Medical Journal)
McLean-Tooke et al have an article (freely accessible on line)
entitled Adrenaline in the treatment of anaphylaxis: what is
the evidence? This review discusses the safety and efficacy of
adrenaline in the light of current available evidence. A pragmatic
approach to use of adrenaline auto-injectios is suggested. Summary
points:
- -Anaphylaxis is a severe life threatening reaction
that can affect all age groups.
- -The severity of previous reactions does not
predict the severity of subsequent reactions.
- -Intramuscular adrenaline is the first line treatment
for anaphylaxis, with intravenous adrenaline reserved
for unresponsive anaphylaxis or circulatory collapse.
- -Early use of adrenaline in anaphylaxis is
associated with improved outcomes.
-Any patient with a systemic allergic reaction should
be considered for an adrenaline auto-injector, depending on
risk of further reactions.
- -There is a clear need to improve education of
both patient and physician on the use of and indication
for adrenaline auto-injectors. 205
(posted Dec 26th, 2003)
- Lack of worldwide availability of epinephrine autoinjectors
for outpatients at risk of anaphylaxis is the titile of a
publication in the May 2005 Annals of Allergy,
Asthma and Immuinology by F. Estelle R. Simons, MD, FRCPC.
According to an investigator-designed, validated survey instrument
that was self-administered by members of the World Allergy
Organization House of Delegates for 2003 to 2005, the responses
were tabulated by country.
- Results: Completed surveys were received from all
75 representatives of all 39 countries (100% response rate).
At the time of the survey, epinephrine autoinjectors that
contained a 0.25- or 0.3-mg dose appropriate for use in
adults were available in 56.4% (95% confidence interval
[CI], 40.8%-72%) of these countries. Widespread
availability in Europe and availability in countries such as
the United States, Canada, and Australia contrasted with
limited availability in Asia, South America, and Africa.
Autoinjectors that contained a 0.15-mg dose appropriate for
use in some children were available in 43.6% (95% CI,
28%-59.2%) of the 39 countries. Autoinjectors that contained
a dose appropriate for use in infants were not available in
any country. Costs ranged from US $30 to US $110. In 27.3%
(95% CI, 8.7%-45.9%) of the countries, no financial
assistance from government or private insurance was
available to defray the cost.
- This study raises concerns about lack of availability and
affordability of epinephrine autoinjectors worldwide for
individuals of all ages, especially for the pediatric
population. (posted May 29th, 2005)
- See review
of the article.
- -Activated charcoal forms non IgE
binding complexes with peanut proteins, is the title of a
study by Vadas and Perlman in the July 2003 J Allergy
Clin Immunol. They report that activated charcoal adsorbs to
peanut proteins, forming insoluble complexes that no longer allow
the peanut proteins to bind IgE. These data suggest that
administration of activated charcoal soon after accidental
ingestion of peanut might be a useful adjunct in the management of
peanut-induced anaphylaxis. This approach is likely to be
applicable to the prevention of more severe and prolonged
anaphylactic reactions to other foods as well. 182
183
(posted July 14th, 2003)
- After some not unexpected comments from the media
following a teleconference held by the AAAA&I on July
10th reviewing this publication and others in the recent
J Allergy Clin Immunol, 2003, these warnings were
released by FAAN (Food Allergy and Anaphylaxis Network) and
the AAAA&I:
- Charcoal
is No Substitute for Epinephrine in the Treatment of
Severe Allergic Reactions to Peanuts and other Foods,
FAAN Warns
- Activated
charcoal should not replace epinephrine in treating
reactions to peanut or other food allergies (AAAA&I) (posted July 14th, 2003)
- Recurrence of
anaphylaxis
- -Mullins R in the Aug 2003 Clin Exp Allergy
studied this issue in Anaphylaxis: risk factors for
recurrence. Of 432 patients (48% male, 73% atopic, mean
27.4 years) 260 patients were seen after their first
episode; 172 experienced 584 previous reactions, 54% of
index episodes were treated in hospital. Food was the
cause in 61%...Accidental ingestion of peanut/tree
nut caused the largest number of relapses, but the highest
risk of recurrence was associated with sensitivity to wheat
and /or exercise. ....
- CONCLUSION: In any one year, 1/12 patients who have
suffered anaphylaxis will experience recurrence, and 1/50
will require hospital treament or use adrenaline.
Compliance with carrying and using adrenaline is poor.
Occasional patients develop new triggers or suffer
psychiatric morbidity. 191(posted
Aug 18th, 2003)
-
- Prévention du choc anaphylactique au cours de
l'allergie alimentaire (Preventing anaphylaxis in food
allergy) is the title of a publication by Eigenmann et
Rancé in the Revue Française d'Allergologie et
d'Immunologie Clinique 43(2003) 533-536
"meant to provide the physician with information on potential risk
situations and on the correct treatment of an eventual
anaphylactic reaction".. Among the authors' recommendations:
- -Avoidance not only of the "visible" food, but also of
the allergen present in processed foods.
- -Careful reading ot labels on all foods purchased.
- -Sticking to processed foods that the patient is
familiar with (although ingredients can be changed without
notice)
- -Help of a dietician in some cases.
- -Education is essential: particularly informing the
entourage of the allergic child (teachers, classmates,
etc.)
- -Adolescence is an age presenting particular risks that
should be addressed. 206
(posted Dec. 31, 2003)
-
-
- When
should epinephrine (adrenaline) be
administered?
-
- -This remains a difficult and touchy question.
- -There is no question that epinephrine administered by
means of a subcutaneous or intramuscular injection is the
treatment of choice for anaphylaxis;84,
85,
62
Other medications such as antihistamines, inhaled asthma
medications, or steroids, that subsequently may be given by
physicians in treating anaphylaxis should not be regarded as
first-line medications. (Position statement 34 of the AAAA&I
(American Academy of Allergy, Asthma and Immunology) Board of
Directors: Anaphylaxis
in Schools and other childcare settings)
This position of the AAAA&I, an
endorsement of a consensus statement originally drafted by the
Canadian Society of Allergy and Clinical Immunology (CSACI) with
its provincial affiliates and allergy organizations in 1996,
further states "epinephrine is the first drug that should be
used in the emergency management of a child having a potentially
life-threatening allergic reaction. . .
- -In patients who have had
anaphylactic reactions, it is recommended that epinephrine be
given at the start of any reaction occurring in conjunction with
exposure to a known or suspected allergen. In situations where
there has been a history of a severe cardiovascular collapse to an
allergen, the physician may advocate that epinephrine be
administered immediately after ingestion of the offending food
and before any reaction has begun.Anaphylaxis
in schools and other childcare services
(CSACI) (now
available in pdf
format).
-
- -The CSACI consensus further states in
the Appendix 2 section dealing with the Management of Specific
Allergens, specifically peanut, re: "Suspected or actual
contact with a known allergen": The child should be under close
and constant supervision for 4 hours after the suspected
ingestion. Administer the epinephrine auto-injector as soon as the
child develops any one of the following symptoms and take him or
her immediately to hospital. If no serious reaction occurs within
4 hours it is unlikely to occur.
- Hives
- Itching (of any part of the body)
- Swelling (of any body parts)
- Red watery eyes
- Runny nose
- Vomiting
- Diarrhea
- Stomach cramps
- Change of voice
- Coughing
- Wheezing
- Throat tightness or closing
- Difficulty swallowing
- Difficulty breathing
- Sense of doom
- Dizziness
- Fainting or loss of consciousness
- Change of colour
-
- -The Allergy Section of the Canadian Pediatric Society, in
1994 had published a similar position statement in the
Journal of the Canadian Medical Association: Fatal
anaphylactic reactions to food in
children.
Here is part of the
statement:
- The goals of pharmacologic treatment are
to maintain airway patency and systolic blood pressure. An
epinephrine injection is the initial treatment of choice for
anaphylaxis: it suppresses release of mediators of
inflammation from mast cells and basophils, and it directly
decreases vasodilation, oedema and bronchoconstriction.
Epinephrine must be administered promptly at the first warning
symptoms, such as itching or swelling of the lips or mouth,
tightening of the throat or nausea, and before respiratory
distress, stridor or wheezing occur.
-
- -See also:
- Epipen
- Many
Children Have Difficulty With Adrenaline Autoinjections. In
Archives of Disease in Childhood, Doctor's Guide reports
Jan 2, 2002, a summary of this particular problem in a
survey of 86 schools in England. The findings are interesting, and
mention is made of overprescribing adrenaline, the fact that
peanut allergy is outgrown in some cases, and the need for
guidelines. (posted Jan 2nd, 2002)
- Twinject
-
-
- -Dr Hugh Sampson in an editorial in the British
Medical Journal in April 1996, entitled "Managing
peanut allergy" and in his Dec. 1997 publication on Food
Allergy in the JAMA suggests that "food allergic
individuals at increased risk for severe anaphylactic
reactions --that is, patients with histories of previous
severe anaphylactic reactions or asthma, or both -- should
be provided with self injectable adrenaline 11
(such as Ana-Kit or Epi-Pen) and an antihistamine (liquid
diphenhydramine (Benadryl) or hydroxyzine
(Atarax).46
Dr Sampson further states "Laryngeal or pulmonary symptoms
following an inadvertent food exposure should be treated
immediately with epinephrine.63
In the June 1999 issue of the J Allergy Clin Immunol,
Dr Sampson repeats this same indication for epinephrine, and
adds that "it must be stressed to all caregivers that treatment
must be initiated without delay in high-risk patients, and they
must be transported to an emergency facility for further
evaluation and treatment. . ." 72
-
- -In the Aug. 1999 J Allergy Clin Immunol, Yocum
and coll. report on "Epidemiology of anapyhylaxis in Olmstead
County: A population-based study." 87
To classify an event as anaphylaxis, they required:
- -one symptom of generalized mediator release, such
as flushing, itchiness or numbness or tingling of lips,
armpits, hands or feet, generalized itchiness, hives or
angioedema (oral or throat swelling), and red, itchy eyes,
- -and at least one of the following additional
symptoms:
- oral and gastro-intestinal symptoms such as: oral
mucosal itchiness, oral swelling, swollen tongue, palate or
throat, nausea, vomiting, difficulty swallowing, abdominal
cramps or diarrhea.
- respiratory symptoms: rhinitis (sneezing, runny
nose) throat tightness, cough, wheezing, hoarseness, change in
voice, shortness of breath, throat swelling, cyanosis
- cardiovascular symptoms: chest pain, irregular
pulse, lowered blood pressure, rapid pulse, fainting, slow
pulse, orthostasis (unsteadiness or dizziness), seizures and
shock.
- (Only two exceptions to these criteria could classify an event
as anaphylaxis: isolated laryngeal edema or immediate shock and a
syncopal event after injection of medication or a radiocontrast
agent.)
The conclusion from the above criteria is that there's a
fine line between a mild allergic reaction and anaphylaxis, and at
times quite difficult to diagnose an event as not being
anaphylaxis! When in doubt, administer epinephrine. (posted
Sept 24th, 1999)
-In the editorial entitled, 'What should we be doing for
children with peanut allergy' by Hugh A Sampson, published in the
Dec. 2000 Journal of Pediatrics, he has this to say:
"The findings reported by Vander Leek et al105
i.e. having found that the symptoms in the initial allergic reaction
are not predictive of subsequent reactions and that patients who
experience minor symptoms initially may be as likely to develop
life-threatening symptoms during subsequent reactions as patients who
experience more severe intial reactions... ALL patients
with peanut allergy need self-injectable epinephrine immediately
available to treat future, unavoidable reactions."107
(posted Jan 6th, 2001)
-In Europe, the attitude is somewhat different. Dr Etienne
Bidat, Paris and Boulogne, on the AllergieNet website, in Prise
en charge du choc anaphylactique (Management of
anaphylactic shock) suggests the following:
- -"Anaphylaxis is a major emergency in allergy, there is no
time to waste; intervention must be immediate. Anaphylactic
shock is often preceded by signs that need immediate treatment.
These signs may be discreet, and may begin during or soon after
a meal, and treatment should be initiated immediately. . .
rather that wait for progression towards anaphylaxis!
- -These first signs can be: itchiness or swelling of lips,
hives, sneezing or runny nose, red eyes or abdominal cramps. At
this point, an antihistamine is advised taken orally and
medical help sought.
- -At times, the symptoms may be more dramatic as: cough,
wheezing, or vomiting in addition to the above-mentioned signs.
An antihistamine must be taken as well as a bronchodilator for
the respiratory symptoms. In any case, if these signs are not
rapidly ameliorated or stabilized by the treatment, cortisone
taken orally is suggested and medical help sought immediately.
If the reaction is more severe, with general malaise, loss
of consciousness associated with an asthmatic episode,
injection of epinephrine is the first-line treatment."
(posted Sept 24th, 1999)
-According to Moneret-Vautrin and Kanny's article entitled
"Anaphylaxis
in schools and other child-care settings --the situation in
France" in the May 1999 Allerg Immunol (Paris),
things are changing. The "Projet d'Accueil Individualisé"
an emergency health care form is being used by allergologists, and
countersigned by the treating physician in charge of the School
Health Department, with description of symptoms, directives and
treatment to be used. They state that "epinephrine is the first drug
to be used."86
(posted Sept. 24th, 1999)
- -In England, treatment of an allergic reaction to food
is similar. Inhaled epinephrine, now withdrawn in Europe, was
often used. Antihistamines are recommended for mild, urticarial
reactions. Epinephrine is reserved for large dose ingestion of
the implicated food and reactions that are not settling after 5-10
minutes, with the patient taken to a medical facility.
Reactions may settle with antihistamines but epinephrine should
be administered if the reaction seems to progress. (posted
Sept 24th, 1999)
-
- -In the Jan 13, 2001 issue of the Lancet, P W
Ewan, and AT Clark (from the Dept of Allergy and Clinical
Immunology, Addenbrooke's Hospital, Hill's Road, Cambridge, UK)
reported in their article entititled 'Long-term prospecive
observational study of patients with peanut and nut allergy after
participation in a management plan'. The abstract reads as
follows:
"Current advice is poor --doctors give an epinephrine injector
to patients, without training or advice on nut avoidance--so that
further reactions are common and deaths occur. We devised and
assessed a management programme providing advice on nut avoidance
and emergency medication. Unselected referrals with confirmed
peanut or tree-nut allergy were recruited. Severity of the allergy
was graded 1-5 and emergency medication allocated accordingly,
oral antihistamine with or without inhaled or injected
epinephrine. Patients, parents, and school staff received verbal
and written advice on nut avoidance as well as training in
recognition and self-treament of reactions, with a written
treatment plan. At follow-up (more than 13,610 patient months)
retraining was given and details of further reactions obtained."
Their findings are somewhat different from figures mentioned in
the editorial by Hugh A Sampson (see above, posting of Jan 6th,
2001):
- -88 (15%) of 567 patients had a follow-up reaction of
reduced severity.
- -62 of 88 were mild (grades 1-3, mainly cutaneous)
and
- -49 patients used oral antihistamine,
- -6 inhaled adrenaline
- -10 took no treatment
- -12 of 12 patients with a moderate follow-up reaction
improved after inhaled epinephrine.
- -Only 3 (0.5%) of 567 patients, aged 27-40 years, had a
severe follow-up reaction (involving dyspnea) [or
shortness of breath] compared with -12% initially.
- -Only one of 567 patients changed from a mild index
reaction to a severe follow-up reaction.
- -Patients with a moderate/severe (grade 4-5) reaction
were older (median 18 years vs 9 years) and 9 of 26 received
injected epinephrine which was always effective.
- -85% of patients had no further reactions.
- -Severity was related to the amount of nut (or peanut)
eaten.
- Interpretation: "Self-treatment was effective
(inhaled epinephrine for early laryngeal oedema and an
epinephrine injector for severe reactions) but provision
of this treatment, including who should carry
epinephrine, required assessment of allergy severity. Our
management plan was effective, and our results indicate
that patients should be referred to specialist allergy
centres for advice on nut avoidance."108
-
-In the Lancet published later, in May 2001, Bauge,
Cooper, et al. sent a letter to the editors, Management of
peanut allergy, in which they comment, in part:
"We are unsure about parts of the study....exact
duration...concern that there is no control group...without such a
group, results would be limited....presentation of the results are
confusing. We understand the imporance of this study and the
apparent usefulness of education and advice.
- -Reply of the authors (Ewan and Clark): the
duration of the study was 7 years and follow-up reached
13,610 patient-months. 21 of 23 patients with moderate
reactions used an epinephrine inhaler for mild laryngeal
oedema, which was always successful. Nine of 26 patients
with a moderate or severe reaction received an epinephrine
injection...all patients are accounted for....re control
group: acknowledged as a study limitation. A control group
of patients cannot justifiably be left to fend for
themselves when the frequency of follow-up reactions are so
high. Our study underscores the importance of providing a
complete management package for nut allergy, including
detailed advice on nut avoidance together with a treatment
plan and medication for self-administration in case of
further reactions. (posted belatedly Nov 2, 2002)
Dosage
of epinephrine
Adults:
Epinephrine USP 1:1000, 0.3 mg (0.3 mL) In the Nov
2001 J Allergy Clin Immunol , Estelle Simons studied
the absorption of epinephrine in adults and recommends "the
intramuscular injection into the thigh as the preferred route and
site of injection of this life-saving medication in the initial
treatment of anaphylaxis."145
(posted Jan 31st, 2002)
Children:
The dosage recommended is 0.01mg / kilo. What is
available today is Epipen (which delivers 0.3mg or 2ml. of a
1:1000 concentration) and Epipen Jr. (delivering 0.15mg or 2 ml of
1:2000 concentration). Ana-Kit (apparently no longer
manufactured) delivered 0.05, 0.1, 0.15, 0.2, or 0.3 mg, and
dispensed for infants as young as 4 months. Twinject is
available since 2005, in the identical dosages, but with a second
dose if needed. (see below)
-The Canadian Pediatric Society in their 1994 paper
entitled Fatal
anaphylactic reactions to food in
children.
recommended the following dosage schedule:
EpiPen Jr for children weighing 12-25 kg and 0.3 mg IM (regular
dose) for children > 25 kg.
- -The rule that is mostly now followed is the recommendation
in The Canadian Society of Allergy and Clinical Immunology
paper published in 1998, Anaphylaxis
in schools and other childcare services
(now
available in pdf format):
- -EpiPen Jr. for those weighing 15 kg (33 lb.) or less.
- -EpiPen for those weighing more than 15 kg (33
lb.)
- -When dealing with infants, a problem arises of
potentially overdosing the patient, so the practice was
prescribing an epinephrine ampule along with a sterile
syringe/needle and instructions. The question has been
raised, "When hands are shaking and a needle is exposed, will
nervous parents end up dosing epinephrine from an ampule
correctly?" Estelle Simons published her study in the
Dec 2001 J Allergy Clin
Immunol of a group of 18 parents who were "given written
instructions to draw up 0.90ml of epinephrine. They were timed
and results compared with a control group that comprised 18
resident physicians, 18 general duty nurses and 18 emergency
dept nurses.
- The conclusions were: Most parents were unable to draw
up an infant epinephrine dose rapidly or accurately. Most
health professionals drew up the dose rapidly; however, their
accuracy was compromised by inherent variations of epinephrine
concentrations in the ampules, and the inherent difficulty of
measuring low volumes of epinephrine. User-friendly
premeasured epinephrine doses suitable for infants should be
developed."146
(posted Jan 31st,, 2002)
-
-Estelle Simons again, in J Allergy Clin Immunol,
Jan 2002, compared the use of "Epipen Jr
versus Epipen in young children weighing 15 to 30 kg at risk for
anaphylaxis". Children aged 5.4+/- yrs, weighing on the
average 18+/- kgs, injected with Epipen Jr, were compared with
children aged 6.6+/- yrs and weighing 25.4+/- kgs, injected with
Epipen.
- Conclusions: Epipen raised the systolic pressure more
than did the Epipen Jr, but also caused more side effects
(palpitations or other cardiovascular effects, with headache
and nausea, beside the usual tremor, pallor and
anxiety). Dr Simons states that the beneficial
pharmacologic effects and the adverse pharmacological
effects of epinephrine cannot be dissociated. For the
out-of-hospital treatment of anaphylaxis, additional
premeasured, fixed doses of epinephrine would
facilitate more precise dosing in young
children.147
(posted Jan 31st, 2002.)
-King Pharma Canada Ltd. bought the rights to sell Epipen in Canada. Working with Health Canada, they have updated the product monograph. They now recommend Epipen Jr for children 15-30 kg (rather than 0-15 kg as previously recommended.) The regular Epipen covers 30 kg and up. (posted Jan 5th, 2007)
-First-aid treatment of anaphylaxis to food: Focus on epinephrine was published in the May 2004 J Allerg Clin Immuol by Estelle R. Simons. Here's part of her abstract: A therapeutic dilemma is examined: the issue of epinephrine dose selection in an individual for whom no optimal fixed-dose auto-injector formulation exists, and a therapeutic controversy: the issue of epinephrine injection versus an oral H(1)-antihistamine in anaphylaxis episodes that appear to be mild.
- Only two fixed doses of epinephrine (0.15 mg and 0.30 mg) are available. The latter auto-inecttor is used for adults, and recommended for children weighing 15 kilos or more. The dosage for children is 0.01mg per kilo, so for children weighing less than 15 kilos, using Epipen Jr would be overdosing. Likewise, in children weighing between 15 and 30 kilos, Epipen Jr would be underdosing, and regular Epipen overdosing. Until the pharmaceutical industry comes up with auto-injectors containing 0.05mg, 0.10mg, 0.20mg and 0.25 mg Dr Simons recommends:
-
- The decision so use Epipen rather than Epien Jr in a case study of a child weighing 22.5 kilos may be guided by the presence of one or more of the following:
- Concurrent diagnosis of asthma
- Peanut, tree nut, milk, egg, fish or seafood
anaphylaxis
- Poor access to emergency medical services, e.g.
living or vacationing in a remote rural area
- Dysfunctional/chaotic family situation
- No reliable transporation available
- History of previous life-threatening reaction (note,
however, that absence of a history of life-threatening
reaction does not eliminate the possibility of such a
reaction in the future)
-
-
- As for the role of antihistamines, Dr Simons concludes:
The onset of activity of orally ingested antihistamines
does not occur until 40 to 60 minutes after ingestion, and
maximal activity is not achieved until 4 hours. In
anaphylaxis, there are no clinical trials of oral
antihistaminies or the algorithms for their use. In
advance, there is no way to identify individuals whose
anaphylaxis manifestations will be limited to the skin
and for whom an antihistamine will suffice...In three
different cohorts, adverse reactions to peanut and tree
nut became more severe with time in 1/3 or more of
individuals. The detailed algorithms developed
to help physicians decide whether to give epinephrine or an
antihistamine in anaphylaxis are useful in health care
settings; however, in the first-aid treatment of
anaphylaxis in the community, placing the burden of decision
making on individuals without medical training or
resuscitation team backup may not be appropriate. Judgment
may be clouded by fear, panic, denial..We must not forget
that the median time to respiratory or cardiac arrest in
individuals with anaphylaxis from food is 30 minutes.
226
(posted May 24th, 2004)
-
Twinject
auto-injector is now available in Canada. As the name indicates,
it comes with a back-up dose. See video of step
by step directions and video
by Dr. Peter Vadas. (posted Oct. 14th, 2005)
-
What about outdated
Epipens?
- Nancy Wiebe, webmaster of the Calgary
Allergy Network.
has brought this question to my attention. Dr Estelle Simons
published an article addressing this question in the May
2000 J Allerg Clin Immuol entitlled Outdated
EpiPen and EpiPen Jr autoinjectors: past their
prime? The abstract reads as follows:
Twenty-eight EpiPen and 6 EpiPen Jr autoinjectors were
studied 1 to 90 months after the stated expiration date.
Most were not discolored and did not contain precipitates.
Epinephrine bioavailability from the outdated EpiPen
autoinjectors was significantly reduced compared with
epinephrine bioavailability from the in-date
autoinjectors. Her conclusions were:
- "For prehospital treatment of anaphylaxis, we recommend
the use of EpiPen and EpiPen Jr autoinjectors that are not
outdated. If, however, the only autoinjector available is
an outdated one, it could be used as long as no
discoloration or precipitates are apparent because the
potential benefit of using it is greater than the potential
risk of a suboptimal epinephrine dose or of no epinephrine
treatment at all." (posted Dec 10th, 2003)
Should beta-blockers be given to
patients with heart disease and peanut-induced anaphylaxis? A
decision analysis. In the May 2004 J Allergy Clin
Immunol, Tenbrook, JA et al asked this question and arrived at
this conclusion: For peanut-allergic patients who are
postmyocardial infarction or who have congestive heart failure,
the heart disease benefit of beta-blockers outweighs the increased
likelihood of dying from anaphylaxis. Their results suggest that
for these patients, beta-blocker use should still improve
survival. However, the epidemiology of anaphylaxis and effects of
beta-blocker therapy on anaphylaxis incidence and mortality
require further study. 222
(posted May 15th, 2004)
-At the annual AAAA&I meeting held in San Diego,CA in Feb. 2007, Oren et at presented Food-Induced Anaphylaxis and Repeat Epinephrine Treatments. The authors reviewed 40 charts of patients who presented with food-related acute allergic reactions to the Massachusetts General Hospital emergency dept over a one-year period. Of the 40 patients, 35 had an anaphylactic reaction. Forteen of the patients who had an anaphylactic reaction received at least one dose of epinephrine. Of those who received epinephrine, 3 were given a second dose... and these were in peanut and nut related reactions. Concl: among patients presenting to the emergency dept with food-induced anaphylaxis, approx. 21% of those receiving epineprhine were given a second dose. This supports the recommendation that patients at risk for food-induced anaphylaxis should carry two doses of epineprhine. (posted May 5th, 2007)
-
-
-
- Dealing
with peanut allergy in schools
-
-
- - Peanut
sniffing dog. A teenage from Jacksonville, FL asked her
mom for a service dog to deal with her peanut allergy. See the
article and the video. (posted June 12th, 2005)
- -See Peanut Detector Dogs.
Follow-up of peanut
allergic patients, following initial reaction:
- avoidance of any food that may contain peanuts
- Consult food "recalls" at the
following sites: Food
Allergy and Anaphylaxis Network-recalls
or at Canadian
Food Inspection Agency
- Hidden
content of peanut in some foods:
- -Peanut anaphylaxis is a potentially near-fatal or fatal
disease complicated by the fact that peanuts as well as
other food items are commonly used as an adulterant in the
preparation of foods, often hidden.
6,14.
Peanuts are frequently added to Chinese foods, oriental
cuisine generally, snacks, soups, cereals, and baked goods
20
- -At the Feb. 1997 annual meeting of the
AAAA&I, using an ELISA test ('enzyme-linked
immunosorbent assay') Nordlee et al reported their findings
on the analysis of commercially produced food products
labeled either:
- a) listing peanut as the last ingredient,
- b) 'may contain peanut' and
- c) label not listing peanuts.
- Their results: for a): ND (not detectable) to
5000 ppm; for b) ND to 1200 ppm; and for c) ND to
4000 ppm.
- (this means that food preparations may
contain peanut if not mentioned on the
label!!!)
- Brett GM, Bull VJ, Morgan MR
report a study on peanut and sesame allergy, using the ELISA
test. . . "the problem of detection of "hidden" allergens
in food is a major concern for both the industry and
consumers at present. Who might use such assays for
maximum benefit, and in what format they should be
provided, are key questions for food analysts, and the
issues are discussed." (posted jan.3d, 1999)
- In the Oct. 1998
Allergy, Hourihane notes... due to the severity of
reactions induced by peanuts and tree nuts... Justifiable
demands are being made for better medical guidance of the
practice of food labeling for industry and catering
businesses 38.
- In Letters to the Editor of the
Sept 2001 J Allergy Clin Immunology, Altschul,
Sherrer, Munoz-Furlong, and Sicherer, in their letter
entiltled 'Manufacturing and lebeling issues for
commercial products: Relevance to food allergy', they
state...."In January 2001, the US Food and Drug
Administration reported an investigation of food companies
in which it was found that 25% of products contained
undeclared allergenic ingredients, often from
cross-contamination. Ingredient statements such as 'may
contain peanut' are presumably helpful, but they are in fact
poorly correlated with actual risks for contamination and
are therefore frustrating for consumers. There have been
no reports to determine the impact of food labeling
procedures (undeclared allergens, label terminoloy, etc) on
food-allergic individuals and their families. We analyzed
unsolicited calls from consumers to the Food Allergy and
Anaphylaxis Network (FANN) alerting FANN of allergic
reactions from incorrectly labeled commercial products
...Seventy (32%) of the 319 logged calls were associated
with reactions due to ingestion of a product...The
implicated food proteins included milk (84), peanut
(60), nuts (31), egg (14), seeds (5), wheat (2), and
mixed or other allergens (25). Among other types of
problems/label issues reported: cross-contaminated by
unlabeled allergen, visible ingredient not disclosed on
label, allergen newly disclosed on label, completely wrong
contents in package, outer package label different from
individual package label inside, ambiguous terminology,
etc....We suggest that simple language be used (e.g.
milk instead of casein), that allergens be
declared when they are present in spices or natural flavors,
and that precautionary statements such as "may contain..."
not be used unless it is clear that there are no viable
methods of preventing contamination despite good
manufacturing practices...that the industry reduce the
introduction of unintended allergens and ensure accurate
labeling."133
(posted Oct. 10th, 2001)
- Consumer Group Wants Food
Labels to Show Allergens:
- WASHINGTON (Reuters
Health) Oct 5, 2001 - The Center for Science in
the Public Interest (CSPI) petitioned the
US Food and Drug Administration
on Thursday to require food labels to show common
allergens and develop
common manufacturing standards to prevent allergens
from contaminating food. "It's now time for the FDA to
protect those Americans who have food allergies by
requiring all companies to
disclose common food allergens,
using plain English and legible format," Michael
Jacobson, executive
director of CSPI, said in a
statement. A similar petition was filed in May 2000 by
the Attorneys General of New York, Maryland,
Michigan, Wyoming, Ohio,
Tennessee, Connecticut, Vermont, and Massachusetts.
The CSPI estimated that 4 million Americans are
allergic to foods such as peanuts, nuts, eggs,
soybeans and wheat. Each
year 29,000 people visit a hospital after an allergic
reaction, and about 150 people die as a
result. (posted Oct 11th,
2001)
-
- In the Dec 2001
Allergy, Schappi et al published Hidden peanut
allergens detected in various foods: findings and legal
measures. "Undeclared allergens in foodstuffs represent
a major health problem for sensitized persons. Until
recently, most food control authorities were not in the
position to monitor hidden allergens and to take legal
measures against their presence in foodstufs." Using
sophisticated immunoassay techniques, the authors "were able
to detect peanut allergens in various food categories,
cereals, cookies, cakes and snacks." They "legally objected
to products with more than one part per thousand of peanut
contamination. Conclusion: in most cases, food producers,
confronted with their results, were able to detect and
eliminate the sources of the contamination."
142
(posted Jan 14th, 2002)
- In the June 2002 J
Allergy Clin Immunol , Joshi, Mofidi and Sicherer have
an article entitled, Interpretation of commercial food
ingredient labels by parents of food-allergic children.
Among their findings: peanut was the most commonly
restricted food....identified correctly by 54%... while
milk and soy was the most problematic.
- Conclusions: With current
labeling practices, most parents are unable to
identify common allergenic food ingredients. These
results strongly support the need for improved
labeling with plain -English terminology and allergen
warnings as well as the need for diligent education of
patients about reading labels.
160
(posted July 15th, 2002)
- In the March-April 2002
ACI International , Steinman has an article
entitled Hidden Allergens and Nonallergenic Substances,
a follow-up to his 1996 publication in J Allergy Clin
Immunol, Hidden allergens in Foods. The findings
are surprising and very informative, and could be found at
the
AllAllergy.net website that
he manages, in the section Allergy
Advisor.
He has developed a computer software program to help in the
diagnosis and management of allergy and intolerance to
foods. (posted July 19th, 2002)
- There are four kits now
commercially available that can be used to detect peanut
protein in foods 166
(posted Dec 9th,
2002)
- Peanut
test could save lives- A new test that detects trace amounts
of peanuts in processed food could help to save
lives.(posted Feb.10th,
2003)
- In the March 2003
J Allergy Clin Immunol, appeared an article entitled
Monitoring peanut allergen in food products by measuring
Ara h 1 by Pomés A et al. They developed an
immunoassay for a major peanut allergen Ara h 1 to detect
peanut allergen in foods so that the risk of inadvertent
expossure can be reduced. Results: peanut butter contained
the highest amounts of Ara h1. Peanut extracts contained
from 0.5 to 15 mg of Ara h1 per gram of peanut...They
conclude that this new sensitive and specific monoclonal
antibody-based ELISA ... should be useful for monitoring
peanut contamination in the food manufacturing and
processing industry and in developing thresholds for
sensitization or allergic reaction in persons with peanut
allergy.174
(posted April 11th, 2003)
- In the Oct 2003 J Food Prot. Vadas
P and Perelman B have an article entitled Presence of
undeclared peanut protein in chocolate bars imported from
Europe. These are their results:
- 92 chocolate bars, of which 32 were manufactured in
North America and 60 were imported from Europe, were
tested by the Veratox assay.
- None of the 32 North American chocolate products,
including 19 with precautionary labeling, contained
detectable peanut protein.
- In contrast, 30.8% of products from western Europe
without precautionary labeling contained detectable
levels of peanut protein.
- 62% of products from eastern Europe without
precautionary labeling contained detectable peanut
protein at levels of up to 245 ppm.
- Conclusion: The absence of precautionary labeling
and the absence of the declaration of "peanut" as an
ingredient in chocolate bars made in eastern and central
Europe were not found to garantee that these products
were actually free of contaminating peanut protein.
(posted Nov 10th, 2003)194
- Wüthrich B published Lethal or Life-Threatening
Food Anaphylaxis in the Allergy Clin Immunol Int: J
World Allergy Org. vo. 15, 2003, in
which he states, "Foods with "hidden" allergens,
exotic meals in restaurants, sauces, crisps, and snacks
represent a particular risk for food allergics...There
is a need to raise awareness of food allergy and treatment
of anaphylaxis in schools and public places, such as
restaurants, and to provide increased support for those with
potentially fatal food allergies. The food industry
should ensure a policy of comprehensive labeling of
ingedients and improve the technologies for analysis so
that even the smallest amounts of potentially lethal
foodstufss can be clearly identified. A label "may
contain..." is no longer tolerable, both for people with
food allergies and the allergists who have to detect the
cause of the anaphylactic reaction of their patients".
(posted Jan 9th, 2004)207
- In the J Allergy Clin Immunol. 2007 Jul;120(1):171-6. Epub 2007 Jun 4, Hefle et al have a publication called Consumer attitudes and risks associated with packaged foods having advisory labeling regarding the presence of peanuts. Their conclusion: Consumers with food allergy are increasingly ignoring advisory labeling. Because food products with advisory labeling do contain detectable levels of peanuts, a risk exists to consumers choosing to eat such foods. The format of the labeling statement did not influence the likelihood of finding detectable peanut, except for products listing peanuts as a minor ingredient, but did influence the choices of consumers with food allergy. CLINICAL IMPLICATIONS: Allergic patients are taking risks by increasingly disregarding advisory labeling. (posted Oct 6th, 2007) 278
- -Peanut allergy test is the title of an article found on Health Minutes in which an Australian allergist recommends 'a four part strategy to minimize the chances of accidental peanut exposure, especially when eating out or at other people’s homes'. O'Hehir RE and Douglass JA. Risk-minimisation strategies for peanut allergy. Lancet 2007;370;9586:483 (posted Oct 13th, 2007) 280
The 4th recommendation of "teaching their patients to touch a trace of food on their external lip before putting the food in their mouth. If they feel a tingling, burning, or swelling then they mustn't eat anything". has been used before, and mentioned by Rance and Dutau in their 1999 article entitled Rance F, Dutau G.: Peanut hypersensitivity in children. Pediatr Pulmonol Suppl 1999;18:165-7. which was posted in the first chapter, 'Charateristics of peanut allergy' . (posted Oct 16th, 2007)
-
-
- avoidance also of tree nuts, especially mixed nuts,
which may also contain peanuts. Because of peanuts being
considered as nuts in the food industry, labeling a food as
containing nuts, may also mean peanuts. Besides, one third of
peanut allergic atopics, also are allergic to tree nuts 13.
See also: Fruits
called nuts (definitions and photos of different nuts) (posted
June 30th, 2003)
- reading all the labels, remembering that traces
of peanut are not always mentioned. Avoidance of any food
or new preparation if the ingredients are not
known.
- a peanut allergic individual may tolerate foods that
contain tree nuts, as almonds, hazelnuts, in cereals and
chocolate bars and may normally continue eating these
preparations, although sensitization can occur. Could we always be
sure that they will never contain traces of peanuts?
- if the initial reaction was an anaphylactic reaction, an
auto-injector of epinephrine (Epipen or Twinject) should be given
immediately if accidental ingestion occurs, even before evidence
of any reaction, and the patient taken to the emergency of the
nearest hospital. If the initial reaction was hives only,
accidental ingestion does not necessitate epinephrine at once, but
an epinephrine auto-injector should be on hand, and given if signs
of anaphylaxis are observed.
- once a skin test shows a positive reaction to peanuts,
whatever the size, performed on a patient having had an allergic
reaction after eating a food containing peanut, the patient is
considered allergic and should avoid all foods that may contain
peanut. If an accidental ingestion should occur and there is
no reaction, the patient should be reevaluated and if the test is
negative, a challenge should be performed by an allergist in a
hospital setting.
- See the article by Pamela W Ewan in the chapter, "When should
epinephrine be administered?"
- The
management of food allergy in children by Jeff
Williams published in Current Paediatrics, Oct
2002. Practice points:
- Avoidance of the offending allergen is of primary
importance - use dietetic help.
- Do not underestimate the anxiety level experienced by some
families.
- The establishment of local professional networks enhances
education programmes.
- Education of child and family about food allergy should be
extended to teachers and classrooms.
- The indications for the provision of self-injectable
epinephrine are controversial. If prescribed, it must be
underpinned by provision of clear guidelines for its use.
- 'May contain traces of nuts' is a frequently seen
caveat, difficult to interpret, but probably best heeded as
potentially dangerous for the affected individual.
- In the case of peanut or tree nut allergy, the best
advice is to avoid all nuts at all costs: it is often
impossible to be certain about the identification of a
specific nut and some children may be allergic to more than
one variety.
- Aerosol transmission of allergen is possible, the
presenting respiratory symptoms during air travel suggesting
strongly that aerosol spread is a genuine risk, actual
ingestion of peanuts not being necessary. 76
(posted Dec 15th, 2002)167
- Monitoring of IgE-mediated food allergy in childhood is
the title of an article by Thong BY and Hourihane JO, published in
te June 2004 Acta Paediatr. The authors conclude:
A combination of outcome measures, a multidisciplinary approach
involving a dietitian and allergy nurse specialist, and a
management algorithm are useful tools in clinical management.
- CONCLUSIONS: Prospective studies of non-selected
children, optimally from birth cohorts, are needed to
evaluate the effects of such management programmes regarding
FA in childhood.229
(posted July 20th, 2004)
-
-
In summary:
- peanut is a staple food in North America, often
hidden in many foods, without any mention on the label
- sensitization is possible during pregnancy, probable during
breast feeding, possible environmental.
- early introduction in children's diet
- increase in frequency and severity of reactions to
peanuts according to medical literature
- over 70% of initial reactions occurred in children not
having had any contact with peanut!
- learn to recognize symptoms of anaphylaxis that occur
rapidly, not necessarily in this order (hives, swelling of lips or
tongue, difficulty swallowing, tightness in the throat and chest,
itchiness, drooling, wheezing, choking, coughing, voice change,
sneezing, nausea, vomiting, cramps, diarrhea, dizziness, pallor,
loss of consciousness, etc.) anaphylaxis can proceed
rapidly. It must be treated immediately with an injection
of epinephrine (adrenaline) and patient taken to the
emergency room of the nearest hospital. Self-administering kits
are available (Epipen or Twinject)
- allergy to peanuts may be lifelong, although may
disappear in approx. 20% of cases (see postings in
article)
- skin and laboratory tests not good predictors of severity
of reactions, and may remain positive in those that have lost
their allergy,
- prevention
- education
- -An excellent article by Dr. Hugh Sampson
published April 25th, 2002 in the N Engl J Med, in
the Clinical Practice section, summarizes Peanut Allergy as
it is today. Here are some parts quoted that are worth
underlining:
- "In a patient with asthma, the acute onset of severe
bronchospasm in the absence of earlier signs of asthma must always
raise the suspicion of anaphylaxis."
- "Food allergy is the leading cause of anaphylaxis treated
in hospital emergency departments in the United States and many
westernized countries. Food allergy accounts for about 30,000
anaphylactic reactions, 2000 hospitalisations, and 200 deaths each
year in the United States. Allergies to peanuts and tree nuts
account for the majority of fatal and near-fatal anaphylactic
reactions."
- "In a recent series, over 80% of patients who died from
allergic reactions to food were not given appropriate informaton
to avoid accidental food-induced reactions or self-injectable
epinephrine to manage them."
- "People who have life-threatening reactions usually have
asthma and frequently have a history of atopy, including
atopic dermatitis and food allergy as young children."
- "Although similar to anaphylaxis due to other causes, early
symptoms of food-induced anaphylaxis often include oral pruritus
and "tingling,pharyngeal pruritus and a sensation of tightening of
the airways, colicky abdominal pain, nausea and vomiting, and
cutaneous flushing, urticaria, and angioedema."
- "Although the relative epidemic of peanut allery appears to be
a phenomenon of the past two decades, peanuts were first
cultivated in South America about 2000 to 3000 B.C... "
- "America now ranks third only to China and India in peanut
production, with over 40% of the U.S. peanut crop consumed as
peanut butter. Whereas the per capita consumption of peanuts in
China is similar to that of the United States, peanut allergy is
extremely rare in China. In addition, the prevalence of
peanut allergy appears to be rising in the U.S. and other
westernized countries." (In the UK, the prevalence of
sensitization to peanuts increased from 1.3% to 3.2% from 1989 to
1995. In a cohort of American children referred for the evaluation
of moderate-to-severe atopic dermatitis between 1990 and 1994, the
prevalence of allergic reactivity to peanuts was nearly twice as
high as that in a a similar group evaluated between 1980 and
1984....6% of Americans have serologic evidence of sensitivity
to peanuts (i.e., the presence of IgE antibodies specific for
peanut proteins), although the majority of these people will not
have an allergic reaction when they eat peanuts (data from 1988 to
1994)."
- "....fewer than 15% of peanut-allergic patients will react
to other members of the legume family. In addition, other
legumes rarely provoke severe anaphylactic reactions or result in
a lifelong allergy."
- "Infants who have peanut allergy tend to have more severe
reactions as they get older. However, recent studies suggest
that about 20% of young infants who have peanut allergy will
outgrow their allergy, especially if they have low levels of
peanut-specific serum IgE antibodies."
- "...skin tests often remain positive for many years
in children who have outgrown the allergy..."
- "...beta-tryptase levels, a hallmark of mast-cell
activation that is associated with anaphylactic reactions,
usually remain normal in patients with food-induced
anaphylaxis.,"
- "The cause of the rising prevalence of peanut allergy and
the reasons this increase appears to be confined to westernized
countries remain uncertain...A number of factors have been
suggested:
- the growing demand for highly nutritional "quick-energy"
foods has made peanut a staple of the American diet...
- breast-feeding is increasingly common, and peanut
products have increasingly been promoted as excellent
nutritional sources for pregnant and lactating
women.(According to some studies...70% had had their first
allergic reaction after their first apparent contact with
peanuts. Since reactions require previous exposure for
sensitization and since IgE antibodies do not cross the
placenta, these findings suggest that peanut protein was
encountered in utero or through breast milk.)
- Given the immaturity of the immune system at birth, food
allergies are more likely to develop during the first year of
life. The majority of American children are exposed to
peanuts (e.g., peanut butter) in the first year of life, and
virtually all have been exposed by their second birthday.
(In countries where peanut butter is rarely eaten, such as
Denmark and Norway, peanut allergy is much less
common.)
- Differences in the way peanuts are prepared may also
contribute to the increasing prevalence of peanut allergy
as well as to the variations in the rates of peanut allergy
among countries...dry-roasted in the US vs boiled or fried in
China. The higher temperatures required for dry-roasting
increase the allergenicity of the the three major peanut
proteins, more than do the lower temperatures used for boiling
or frying.
- Although genetics play a part in the development of peanut
allergy, the prevalence of peanut allergy is similar among
the children of Chinese immigrants to the US and the children
of native-born Americans.
- "All patients with peanut allergy should be given a written
emergency plan and adequate doses of liquid diphenhydramine and
self-injectable epinephrine for use in case they accidentally
ingest peanuts.
- "Whether peanut allergy can be prevented remains in
question. Nonethelss, the Dept of health in the United Kingdom
(and many allergists in the US) recommend that mothers from
"high-risk" families (those with a history of atopy) avoid eating
peanuts during pregnancy and lactation and that they not give
their infants peanut products for the first three years of
life." (posted May 1st, 2002)154
N.B. Regarding the item above on the fact that peanut allergy is rare in China,
In Clin Exp Allergy. 2007 Jul;37(7):1055-61, Chiang WC, Kidon MI, Liew WK, Goh A, Tang JP, Chay OM, reported The changing face of food hypersensitivity in an Asian community. The authors conclude: In contrast to previously reported low peanut allergy rates in Asia, in our review, peanut sensitization is present in 27% (62/227) of food-allergic children, mostly in patients with multiple food protein sensitizations. Temporal patterns of first exposure of infants to fish and shellfish are unique to the Asian diet. Shellfish are a major sensitizing food source in Asian children, especially in allergic rhinitis patients sensitized to cockroaches. 276 (posted Aug 3d, 2007)
-
- -In the April 2002 of Ann Allergy Asthma Immunol,
Dr SH Sicherer published Clinical update of peanut allergy
in which English language articles were selected from PubMed
searches and selected abstracts with a bias toward recent (3
years) studies judged to have immediate, practical clinical
implications. Results:
- Peanut allergy is an increasing problem in western diets
that include this food....
- heightened risk for those with atopic dermatitis and/or
other food allergies...
- the allergy is long-lived for most, may increase in
severity slightly over time, but approx. 20% of young children
will develop tolerance.....
- improved diagnostic and treatment modalities....
- studies on the way that are likely ot provide more definite
therapies in the near future. (posted May 15th, 2002)
155
-
-
- Recent
studies:
-
- Anti IgE drug: new treatment for
peanut allergy?
-
- -During the month of Dec. 1999, a new drug for asthma
was reported in the media, an anti-IgE monoclonal antibody,
described as acting directly on the allergic component of asthma,
IgE, following a publication the the New England Journal of
Medicine: Treatment of Allergic Asthma
with Monoclonal Anti-IgE
Antibody89.
On Dec. 28th, the Peanut Allergy
Site (PeanutAllergy.com) posted information about a clinical trial
of the drug in severe peanut allergy: "Tanox announces start of
anti-IgE clinical trial." In the same posted announcement,
comments are reproduced from members as well as from Dr Donald
Leung, and Dr Hugh Sampson, both involved in the trial. "In
this study we are attempting to determine whether or not anti-IgE
therapy will be effective in preventing anaphylactic reactions to
peanuts. If it is effective in peanut allergic patients, it is
very likely that it will actually protect allergic patients from
all food allergies. . . We are very optimistic about this
medication. . . " (posted Dec 31st, 1999)
- -Sept 24th, 2002:
FDA
Grants Tanox's Peanut Allergy Drug Fast Track
Status....it
means that the FDA will facilitate the development and expedite
the review of a drug if it is intended for the treatment of a
serious or life-threatening condition and demonstrates the
potential to address unmet medical needs for such a condition.
- Fast track status enables a pre-BLA
(Biologics License Application) meeting with the FDA to discuss
and achieve agreement on critical issues, allows for early
submission of portions of the BLA in order to expedite review
and presents performance goals for priority review of the BLA
in six months for the specified indication. (posted Oct. 7th,
2002)
- -In the Montreal
Gazette of Sat. Oct. 5th, 2002, appeared a Canadian
Press item entiltled: 'U.S. fast tracks peanut-allergy
drug', a follow-up to the above announcement. The article
states that
- "there currently is no treatment
for peanut allergy, one of the most severe forms of food
allergies... According to a conservative estimate, two per
cent of Canadians (about 600,00 people) might be affected by
potentially life-threatening allergies. The incidence might
be higher in children and it has increased dramatically in
the last decade.
- For many people with peanut
allergies, contact with even trace amounts of peanut protein
can bring on a life-threatening attack of anaphylactic
shock. People suffering an allergic reaction to peanut must
be given an immediate jab with an Epi-pen, a device that
dispenses epinephrine.
TNX-901, administered by injection,
would protect against reactions to accidental peanut exposure
by binding to the allergic antibody and blocking it from
circulating through the system.
- Despite the fast-tracking, it
could still be years before the drug passes through all the
necessary trials and hists the market.(posted Oct. 7th,
2002)
-
- -Also in the Boston
Globe, Oct 7th, 2002: 'Scientists make gains against
peanut
allergy'...''I
think that, within five years, there will be treatments that
will do two things,'' said Dr. Wesley Burks of the
University of Arkansas, who is working on the vaccine. ''One
will lessen the chances significantly that an accidental
ingestion would be life-threatening, and the second is that,
if the vaccines work appropriately, there are chances the
child would eventually no longer have the
disease.''....
'It's the first time that we have been
able to look to the future and actually believe that a cure or
a treatment is within reach,'' said Anne Munoz-Furlong, founder
of the Food Allergy and Anaphylaxis Network, a national
advocacy group that educates the public about food allergies.
''It's a very exciting time. Ten years ago, we were still
trying to figure out how big the problem was, and many people
didn't believe it was serious.''
-
-At the 60th Anniversary Meeting
of the AAAA&I held in Denver, Colo. March 7-12,
2003,
Dr Leung presented the results of the first study on
the
Effect of Anti-IgE Therapy in Patients with Peanut
Allergy..coincidingly published in the March 13th, 2003
New England Journal of Medicine. A double-blind, randomized,
dose-ranging trial was conducted in 84 patients with a history
of immediate hypersensitivity to peanut. Three different doses
(150, 300 or 450 mg of TNX-901)were given to randomly assigned
groups every four weeks for four doses. The patients underwent
a final oral challenge within two to four weeks after the
fourth injection of the vaccine.
- Results and conclusions: A 450 mg dose of TX-901
significantly and substantially increased the threshold
of sensitivity to peanut on oral food challenge from a
level equal to approximately half a peanut (178 mg) to
one equal to almost nine peanuts (2805 mg), an effect
that should translate into protection against most
unintended ingestions of peanuts.
- The authors conclude that "although these results
are highly encouraging, TNX-901 is still an experimental
drug, and approval for general use will require
confirmation of these results in additional
studies."170
(posted Mar 28th, 2003)
- -Comments from Drs RA Nicklas, and BA Chowdhury,
Division of Pulmonary, Allergy and Drug Products, US Food
and Drug Administration, published as a guest editorial
in Annals of Allergy, Asthma and Immunology,
entitiled Effect
of anti-IgE therapy in patients with food allergy
include the following:
- -"....the study contains several imporant
potential biases....which could lead to false
expectations on the part of both physicians and
patients.
- -Two patients with negative food challenges
were entered in the study.
-Open challenges were used, which automatically
introduces bias, both on the part of patients and
investigators.
- -The fact that 3 of the investigators were not
blinded to the study results enters further bias into
the study.
-There is concern that physicians will conclude
from these data that TNX-901 may offer protection for all
patients. In fact, 76% of pateints were not
protected against a reaction after ingestion of 8 g.
of peanut flour (equivalent to 24 peanuts), and
approximately 25% were not protected after ingesting
as low a dose as 0.5 g of peanut flour (approx. equal to
1.5 peanuts), despite being pretreated with the highest
dose of TNX-901.
- -Even if it is expected that TNX-901 has a
beneficial effect...it cannot be expected to
protect every patient sensitized to peanut from an
anaphylactic reaction after ingestion of even small
amounts of peanut allergen...Unless those
patients who are not sufficiently protected can be
identified, physicians will have to assume that all
patients are at risk and will still need to carry
injectable epinephrine as well as assiduously avoid
exposure to food allergens to which they are
sensitized. (posted Nov 8th, 2003)
-
A chinese herbal formula studied in a mouse
model
-In the Oct 2001 J Allergy Clin
Immunol, Li and coll. published their study entitled "Food
Allergy Herbal Formula-1 (FAHF-1) blocks peanut-induced anaphylaxis
in a murine model." Laboratory findings suggest that this Chinese
herbal formula may prove valuable for the treatment of peanut
allergy.134
(posted Nov 7th, 2001)
-The same authors (Li, Sampson and
coll.) published a follow-up study in the Jan 2005 J
Allergy Clin Immunol entitled The Chinese herbal medicine
formula FAHF-2 completely blocks anaphylactic reactions in a murine
model of peanut allergy. They removed two herbs from the original
formula (FAHF-1) and found that the new product, FAHF-2, completely
eliminated anaphylaxis in mice allergic to peanut challenged as long
as 5 weeks posttherapy. Acc'g to the abstract, 'this result was
associated with downregulation of TH2 responses. FAHF-2 may be a
potentially effective and safe therapy for peanut allergy.' 241
(posted Jan. 15th, 2005)
-
Study on oral administration of IL-12
-
-Lee, and coll. in the Nov 2001 Clin Immunol
published their study entitled "Oral administration of IL-12
suppresses anaphyactic reactions in a murine model of peanut
hypersensitivity." They also conclude that this preparation has
therapeutic as well as preventive effects on peanut allergy.
135
(posted Nov 7th, 2001)
-In the 2002 Spring Newsletter of Anaphylaxis Canada, Dr.
Peter Vadas' presentation at the Canadian Society of Allergy and
Clinical Immunology meeting held in Oct. 2001 is summarized in the
Current Research section.
- "All in all, the future looks very bright. Dr Vadas
believes that we will start to see the application of some
these experimental treatments within the next few years.
The major areas of international research are;
- Modified peanut protein vaccine The major peanut
proteins can be modified so that they do not bind with IgE
(bypassing IgE) but still stimulating an immune response
blocking a reaction should unmodified peanut protein be
introduced at a later date.
- DNA vaccines: There are four DNA-based modalities
that are currently being investigated. In one study it was
found that when mice were given the major peanut allergen gene
by mouth (i.e. the gene that directs production of one of the
major peanut protein allergens), the gene began to function
within the cells of the gut and these mice showed a reduction
in the development of anaphytlaxis to peanut.
- A chinese herbal remedy: referring to the posting
above. Studies are currently underway to understand the
mechanism and determine the role that this derivative could
play in anaphylaxis treatment of humans.
- Anti-IgE vaccine: following the research mentioned
in the above posting (going back to Dec 1999) a medication that
was developed for the treatment of asthma and allergic rhinitis
may find a new application in the pevention of anaphylaxis.
This vaccine may be capable of reducing the severity of an
anaphylactic reaction through blocking IgE. Clinicl trials are
underway and will be starting in Toronto shortly.
- Th1-Th2 shift: Certain probiotic bacteria,
such as lactobacillus, that do not cause infection in humans,
may provide some degree of protection against the development
of allergy. This is in keeping with the 'hygiene hypothesis' of
allergy whereby it is believed that the presence of certain
bacteria can shift the immune system away from the allergy
pathway... the so-called Th1-Th2 shift.' " (posted April 18th,
2002)
See also:
-CBS
news and video on the effect of roasting peanuts, and more on a
vaccine for peanut allergy-interview with Dr. Hugh Sampson
(posted Dec. 4th, 2002) At the same page, see another
video:
-In the June 2002 Curr Opin Allergy
Clin Immunol, Dr JO Hourihane has an article entitled
appropriately Recent advances in peanut allergy. (Abstract)
Highlights:
- "Peanut dominates the list of foods implicated in fatal
allergic reaction to food. 110
This dominance has understandably led to greater fear of peanut
than other foods when assessing the community care needed for
peanut allergic individuals. The reasons for this dominance are
still not clear.
- Peanut ... is highly allergenic (animal studies have
shown that peanut is more allergenic than cow's milk: higher IgE
levels in sensitized mice.)
- ...the immune response may not exclusively be committed to
IgE production.
- The major allergen Ara h2 has been sequenced, with a deduced
structure of 207 amino acid residues. The use of modified
allergens for immunotherapy depends on, among other factors,
decreasing IgE binding capacity to stimulate T cells, because
tolerance is an active immunological process, rather than simply
the absence of sensitization (shown in studies in mice).
- ...sensitization by unidentified or occult
exposure...which has led to the concept of in-utero exposure
or via breast milk. See study by Vadas et al115
...It is intriguing that only half of the participating
mothers expressed peanut (in the breast milk) and one mother
expressed peanut in breast milk more slowly and for longer than
the other 10 participants...
- The nature of the allergen may also be a significant
difference because peanut is a staple food in many developing
countries, with similar volumes of consumption to those in
North America. The american pattern of peanut consumption
is to eat peanut raw or roasted, not boiled or fried, as it is in
African and Asian populations, where peanut allergy is very
uncommon. Roasting of peanuts increases IgE binding (by
production of advanced glycation end products that render proteins
more resistant to acid digestion.) Boiling or frying decreases
IgE binding.
- Peanut consumption in Sweden (roasted peanuts, not peanut
butter which is rare) has only increased by 5% between 1996 and
1999, but the number of specific IgE tests requested for peanut
has nearly trebled (young children identified as most
affected). This is probably due, at least partly, to increased
awareness and ascertainment bias....only 60% of positive
results were associated with clinical reactivity, with
symptoms more common with higher CAP class results, as
expected.
- A major point of anxiety for parents and uncertainty for
clinicians has been what to advise for children with mild
reactions to peanut. Clinical severiy can increase over time,
acc'g to cross-sectional questionnaire reviews and studies,
supported by a longitudinal study, but a recent British study has
contrasting findings. Initial reactions occur in the home, future
reactions elsewhere (restaurants, acc'g to The Peanut Allergy
Register of the Food Allergy Network, findings showing
increased severity with subsequent exposures.)126
Vander Leek followed annually a group of 102 children
whose peanut allergy was diagnosed before the age of 4 years. Mild
initial reactions were followed by further reactions in 70% of
cases, with 44% being more severe. Even mild skin reactions
to oral contact followed the same atten on re-exposure...this
study confirmed previous findings that severe peanut allergic
reactions predict future severe allergic reactions.
.105
- ... but peanut allergy can resolve (see posted studies
above) It may be that the increased severity with age actually
partly reflects resolution in childhood of more minor degrees
of allergy to peanuts. ...initial minor skin reactors are
more likely to outgrow peanut allergy....but no individual
with severe initial reactions achieved tolerance.
- As in other studies, the prevelance of other atopic
diseases was lower in those who tolerated peanut than in those
with persistent disease.
- ...a negative skin prick test with peanut virtually
eliminates the likelihood of a positve reaction to peanut during a
challenge.
- re reactions in schools:
- most reactions in children occur outside the school
environment, at home or in restaurants (the frequency of
the latter increases with age). An allergic reaction in
school can, however, represent the first reaction in 25% of
peanut allergic individuals.
- Study in Michigan: 55% of responding schools reported more
than 10 identified food allergic pupils enrolled. Only 16%
had a written individual care plan for each food allergic
pupil. The situation is slightly better if the food
implicated is peanut: a small proportion of the 73 schools
with peanut allergic pupils provided most of the examples of
designated classrooms, use of Medic Alert identification and
personalized care plans.
- ...interesting difference between what a school reported as
their intended response to an allergic reaction and what others
found when they looked at the problem from a 'consumer' point
of view. Ninety-four percent of schools reported that they
would transfer the child to a medical facility and only two of
109 schools said they would contact the child's parents for
further assistance. In fact, schools contacted parents
to 'find out what to do' after 60% of actual reactions and in
32% the parents noticed signs of reaction simply when picking
their child up from school.
- Data from recents studies imply that the mere presence
of an information pack and action plan decreases the incidence
of allergen exposure at home and in school and day care
facilities.... A personalized care plan can decrease the
rate of re-exposure to peanut and other food allergens....they
should be reviewed regularly. Training of new members of staff
and retraining of existing staff essential. Doctors and allied
professionals should provide these programmes rather than
parents.
- Significant progress is being made using animal models and
identification and modification of peanut allergen structure,
which may soon lead to human trials of immunomodulation using
modified proteins or DNA based vaccines. "
- 157
(posted in summary form July 6th, 2002, more detailed
Oct 21st, 2002)
- He suggests:
- A better sharing of information and communication between
families, schools, restaurants, which would reduce the incidence
of severe réactions when being exposed to peanut ouside of
the home. The severity of the reactions to peanut could increase
with age but approximately 25% of young allergics could lose their
peanut allergy.
- Programs of personalized care and education which would
have an impact or the avoidance of peanuts and appropriate
responses of the care providers.
- It is important to remember that the allergenicity of
peanuts is altered by the way peanuts are prepared; roasting seems
to increase the allergenicity compared to boiling or
frying.
- An encouraging note is that immunotherapy with modified
peanut allergens et DNA vaccines are near the clinical study
stage. 157
(posted July 14th, 2002)
-
- -Likewise, Shimamoto and Bock, in the same June
2002 Curr Opin Allergy Clin Immuno issue, have
Update on the clinical features of food-induced anaphylaxis.
It is a review on food-induced anaphylaxis, its prevalance,
proposed etiology, a discussion on exercise-induced anaphylaxis
that may be triggered by specific foods, at times not, an attempt
at identification of specific food antigens responsible, and
current treatment options available (patient education, food
avoidance, acute symptom recognition, and early use of
self-administered epinephrine.) Additionally, they discuss
outcome data regarding the morbidity and mortality related to food
allergy and anaphylaxis, and information regarding experimental
immunomodulatory therapy.
158 (posted July 6th, 2002)
-
- -Update on food
allergy. Sampson HA May 2004 of J Allergy Clin
Immunol. Here's the abstract:
-
- "Tremendous progress has been made in our understanding
of food-based allergic disorders over the past 5 years.
Recent epidemiologic studies suggest that nearly 4% of
Americans are afflicted with food allergies, a prevalence
much higher than appreciated in the past. In addition, the
prevalence of peanut allergy was found to have doubled in
American children less than 5 years of age in the past 5
years. Many food allergens have been characterized at the
molecular level, which has contributed to our increased
understanding of the immunopathogenesis of many allergic
disorders and might soon lead to novel diagnostic and
immunotherapeutic approaches. The management of food
allergies continues to consist of educating patients on
how to avoid relevant allergens, to recognize early
symptoms of an allergic reaction in case of an accidental
ingestion, and to initiate the appropriate emergency
therapy. However, the recent successful clinical trial of
anti-IgE therapy in patients with peanut allergy and the
number of immunomodulatory therapies in the pipeline provide
real hope that we will soon be able to treat patients with
food allergy." 224
(posted May 15th, 2004)
-
- -In the Oct 2004 BMJ
, Wendy Hu, Andrew Kemp and Ian Kerridge, from the School of
Public Health and Community Medicine, University of New South
Wales, from the Dept of Allergy, Immunology and Infectious
Diseases, Childrens' Hospital of Westmead, and from the Centre for
Values, Ethics, and the Law in Medicine, Sidney, Australia,
published 'Making
clinical decisions when the stakes are high and the evidence
unclear'.
- The article is worth downloading- it addresses many issues
related to dealing with peanut allergy particularly its
management. In the words of the authors, 'Children with peanut
allergy are often provided with adrenaline (epinephrine) in
case of a severe reaction. The probability of a
life-threatening reaction is low, however, and the criteria for
provision are controversial. How should the costs and benefits
be balanced?' (posted Oct. 9th, 2004)
-
- -Burks W, Lehrer SB, Bannon GA. have a publication in Clin
Rev Allergy Immunol. 2004 Nov; entitled
New approaches for treatment of peanut allergy: chances for a
cure. Here's part of the abstract:
- "Strict avoidance of specific foods is accepted treatment of
food-induced allergic reactions but is often an unrealistic
therapeutic strategy for the treatment and prevention of
food-induced hypersensivity reactions for many reasons. Desirable
therapeutic strategies for the treatment and prevention of the
food allergies must be safe, relatively inexpensive, and easily
administered. Recent advances in the understanding of the
immunological mechanisms underlying allergic disease and better
characterization of food allergens have greatly expanded the
potential therapeutic option for future use. Several different
forms of immunodulatory therapies are currently under
investigation: peptide immunotherapy, mutated protein
immunotherapy, allergen DNA immunization, vaccination with
immunostimulatory DNA sequences, and anti-immunoglobulin
E-therapy."242
(posted Jan. 19th, 2005)
-
-
-
-
-
Questions:
-
- The question that everyone is asking, and to which there is no
clear-cut answer is: will all children that have reacted
to peanuts by having urticaria only, usually on the face, of short
duration that resolved without any treatment, that show a positive
skin test to peanut, progress to life-threatening anaphylaxis,
after accidental ingestion?
-
- Jan 28th, 1999. When seeing siblings of peanut
allergic children particularly, but not
necessarily, allergists are often asked to check to see if they
are allergic to peanuts, or nuts. They have no history of
reaction of any kind to peanuts, or nuts, and in many cases,
arising from fear, or for any other reason, they have never
eaten peanuts or nuts. Based on the recent medical literature,
with initial reactions occurring in more than 70% of cases without
previous contact, should they be tested for peanut allergy?
-
- If the test is negative, the sibling is considered
not allergic, what are the recommendations? Should
she/he eat peanuts?
- Answer: According to Dr. Anne Des Roches: if
the sibling with a negative history of peanut or other food
allergy, has a negative skin test, in the case of a very young
child, introduction of peanuts not before age 5. (posted April
18th, 1999)
-
- If on the other hand, the test is positive, and
strongly positive perhaps, the child obviously is considered
allergic, and continues not eating peanuts or nuts. Can one
conclude that the child would have had an allergic reaction,
possible even anaphylactic, had he or she eaten peanut, and
doing the test in such cases is a preventive measure?
-
- To help answer these questions:
- In a 1996 article in the BMJ, Peanut
allergy in relation to heredity, maternal diet, and other atopic
diseases: results of a questionnaire survey, skin prick testing,
and food challenges. Hourihane and coll. reported
their findings in a survey of people with self reported peanut
allergy or referred by their physician for suspected peanut
allergy, in relation to heredity, maternal diet, and other atopic
diseases:
- all forms of atopy were both more common in successive
generations and more common in maternal than paternal
relatives
- peanut allergy was reported by 0.1% (3/2409) of
grandparents, 0.6% (7/1213) of aunts and uncles, 1.6% (19/1218)
of parents, and 6.9% (42/610) of siblings
- consumption of peanuts while pregnant or breast feeding was
more common among mothers of probands (children with positive
histories of peanut allergy) younger than 5 yrs of age, than
probands over the age of 5.
- age of onset correlated inversely with year of birth
- skin prick testing of 50 children with reported peanut
allergy . . . 14% were negative. No parent and 13% (5/39) of
siblings had a positive result on skin prick testing for
peanut. Two of these siblings had a negative challenge with
peanuts. The prevalence of peanut allergy in siblings is
therefore 7% (3/39).
-
- Conclusions:
-
- Peanut allergy is more common in siblings of people
with peanut allergy (7%) than in the parents or the general
population (1.3%).
- Its apparently increasing prevalence may reflect a
general increase of atopy, which is inherited more
commonly from the mother.
- Peanut allergy is presenting earlier in life,
possibly reflecting increased consumption of peanut by pregnant
and nursing mothers 44.
(posted Feb 13th, 1999)
- According to Hugh Sampson, . . . "infants at increased risk
for developing peanut or nut allergy should be identified. These
are infants from atopic families or families with other food
allergies or atopic disorders. Their parents should be advised to
eliminate all peanut products from the child's diet for at least
three years, and mothers who are breast feeding should eliminate
peanut products from their own diet. Children under 3 years of
age who are being evaluated for other allergies should be tested
for peanut allergy, and any child with peanut specific IgE
antibodies should avoid all peanut and nut products for three to
five years. If no reactions to inadvertent ingestions have
occurred in the interim, the child should be reevaluated for
evidence of peanut and nut specific IgE antibodies and clinical
reactivity to peanuts." 46.
(posted Feb 13th, 1999)
-
See also: "Predictive
value of skin tests"
-
- Some questions that were asked of Dr Pamela W. Ewan following
her article: Clinical study of peanut and nut allergy in 62
consecutive patients: new features and associations, published
in the BMJ 33
in 1996, found on the Internet at Mediconsult.com are
reproduced here:
-
- 1. Could eliminating exposure to peanuts and nuts in
childhood prevent the development of allergies?
-
- That's difficult to answer. We need much more data over a
long period of time to be certain. One of our hypotheses is
that the early introduction of peanuts is an important factor
responsible for the increase in peanut allergy. If that's
right, delaying introduction might lead to prevention of
this
- allergy. It's known for certain in other allergies that
small children, if exposed to a potent allergen, seem to be
more likely to react. We have not seen this large number of
young children with peanut allergy until recently, so something
has changed, and one of a number of things that have changed
is
- diet.
-
- 2. Have you seen cases of adults who have been eating
peanuts all their lives, and suddenly get a reaction?
-
- Very few. We do see that, but it's uncommon, although
allergies can develop at any age.
-
3. Can skin tests be dangerous to young children?
-
- Skin tests are very safe, but it's important that they be
done in expert hands, because occasionally you get a reaction.
We tested large numbers of nut-allergic people, including very
young ones, and we saw no adverse reactions.
-
- 4. Do genetic factors predispose to nut allergy or other
allergies?
-
- That's certainly true of other allergies, and I presume
that it will apply to nut allergy as well. It has been known
for a very long time that if one parent is allergic, there's a
good chance the child will be, and if both parents are, the
chance is even greater. But it's not a direct inheritance. It's
very complex trying to disentangle the link between genes and
the development of allergic antibody responses. In
- this study, almost all of the patients who were
nut-allergic also had other common allergies, so they were
clearly of a background genetically predisposed to
allergy.
-
- 5. Can an infant be sensitized through breast milk?
-
- Probably. We know that proteins from the maternal diet can
get into breast milk. This has been established with other
foods, so there's no reason it couldn't happen with peanuts,
although as far as I know this hasn't been properly
demonstrated. You must have been previously exposed in
order
- to produce the antibody which causes the allergic reaction,
so theoretically it couldn't occur on your first exposure.
Cases where the mother is sure that a reaction occurred the
very first time the baby was given peanut in any form raise
issues like "Could it have been from breast milk?". It's
- postulated that tiny amounts of the protein in the mother's
milk might be enough to sensitize the baby -- in other words,
cause him to manufacture the harmful allergic antibody to the
protein. Another possible way could be across the placenta, in
utero. If the mother is eating a lot of peanuts
- during pregnancy, it's theoretically possible for the
proteins to cross the placental barrier into the baby.
-
- 6. To what factors do you attribute the increase in
allergies?
-
- In the last 10 to 20 years, there has been a huge increase
in the number of allergic disorders. Earlier or more frequent
exposure to allergens is one important factor, but I don't
think it's the only one. Another is atopy, the tendency to form
allergic antibodies. An atopic child exposed to peanut butter
is at much greater risk of developing peanut allergy than a
normal child. We found atopy in 96% of the patients in the
study by carrying out skin prick tests to other common
allergens. The same number had other common allergic disease --
allergic asthma or rhinitis, or atopic eczema. One
- theory is that it's in part to do with modern living. The
way we live now, in enclosed environments with central heating,
carpets and double-glazed windows, favours the growth of the
house dust mite, which is one of the commonest causes of
asthma, rhinitis and eczema. That may be a very
- important factor, and there may be others that we don't yet
have data on.
-
- Comment from Dr. Ewan:
-
- One thing our study suggests is that if you have a child
with a common allergy, it's very unwise to give that child
peanuts or nuts. It may well be that the same advice is valid
even for children who aren't allergic, but we don't yet have
data to support that. But if you have an allergic child, there
are
- very strong reasons for at least delaying the introduction
of peanuts and nuts, and certainly to not give them to very
young children. It's a fearsome allergy -- it's a very
dangerous thing to have. It can have such terrible
consequences, so if there's any way of avoiding it, that would
be sensible to
- do. (posted April 21st, 1999)
- See also: Ewan
PW, Clark AT: Long-term prospective observational study of
patients with peanut and nut allergy after particiption in a
management plan. Lancet 2001;357: 111-115.
-
-
-
- Related links:
- -Allergy Haven (very informative site)
- -'Don't go nuts (UK) Nut Allergy Information & Forum for the UK & Beyond.
- -No Nuts for me'-interactive video for kids.
- -Practical aspects of adverse reactions to peanut by Karen du Plessis and Harris Steinman. Current Allergy& Clinical Immunology, March 2004 Vol 17, No. 1
- -Peanut allergy (pdf document from Australia)
- -Tree nut allergy by Susanne Teuber. See also her video: Food Allergy : Challenges for Physicians , Food Scientists and the Food Industry
- -Peanut and Other Food Allergies -- Scott Sicherer, MD -- 07/24/03.
- -Allergens in food, by Wesley Burks, from the 2002 Postgraduate Sessions of the AAAA&I Meeting.-Peanut allergy huge challenge for parents
- -Peanut and nut allergies- The facts (Brochure from the AAIA)
- -Peanut allergy - No small thing- Video of conference given by Dr Rhoda Kagan. (posted June 30th, 2003)
- -Penaut allergy: an overview. Excellent review by Saleh Al-Muhsen, Ann E. Clarke and Rhoda S. Kagan (full text available)
- -Peanut allergy...;how much do you know? Michigan State University extension
- -Peanut allergy - UK Dept of Health 47 page document by the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment.
- -Sicherer SH, and Sampson HA: Peanut and tree nut allergy: Current opinion in Pediatrics 2000;12:567-573
- -Peanut Allergy by prof. P. Potter (Allergy Society of South Africa)
-
- -Understanding food allergy
- -Food Allergy and Anaphylaxis Network-Peanut Aware
- -Peanutallergy.com
- -Peanut allergy links
- -MedicAlert
- -Ident-Id
- -"Kids with food allergies" is an online support group for parents of children with severe food allergies and anaphylaxis
- -Peanut allergy information for families
- -Cracking it? Peanut allergy - is an answer close? (Hourihane, JO)
- -Severe food allergies in kids on rise-Experts say peanuts responsible for about half the problem (video) (posted May 12th, 2002)
- -Food Allergen Consumer Protection act (posted May 12th, 2002)
- -$10M Granted in First Plaintiff Victory in Food Allergy Case (posted May 12th, 2002)
-
- -Food allergy- a review by Scott H. Sicherer, Lancet 2002;360:701-10
- -A Snapshot of Federal Research on Food Allergy : Implications for Genetically Modified Food-Food Allergy Initiative
- -Primary Care Approaches: Peanut Allergy: An Increasing Health Risk for Children, from Pediatric NursingPatricia L. Jackson
- -Guidelines, Recommendations on Peanut Allergy from the American Academy of Family Physicisans
-
- -Awareness of Peanut or Nut Allergies amongst Canadians
- -Food Allergies and School : What Every Parent Should Know
-
-
-
-
-
-
References:
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F, Dutau G.: Labial food challenge in children with food allergy.
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accessible)
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- John Weisnagel, M.D. formerly of the Allergy Service,
Dept. of Pediatrics, Hôpital Ste Justine, Montreal,
Qué. until Dec. 2000, is a pediatrician and allergist in
private practice since 1962, now at Polyclinique Médicale
Concorde, 300 est boul. de la Concorde, Laval, Qué. H7G
2E6. Past president, for many years, of the Association of
Allergists and Immunologists of Quebec (AAIQ). Member of the
Canadian Society of Allergy and Clinical Immunology (CSACI), and
of the American Academy of Allergy, Asthma and Immunology
(AAAA&I). The 2002 CSACI recipient of the Jerry Dolovich Award
for Contributions to Allergy and Clinical Immunology in
Canada.
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(Article originally posted Oct 2nd, 1998. Updated regularly. Any
comments and modifications are welcome.)
Last update: Oct. 27th, 2009
This article is continued in part 2
J.W
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jweis@videotron.ca