Asthma and food allergy

PURPOSE OF REVIEW: Food allergy associated clinical and social burdens have increased substantially in prevalence in the past decade. Coexisting asthma is a significant problem as food reactions tend to be more severe when they involve the lung. Food allergy also increases asthma morbidity in adults and children. RECENT FINDINGS: Especially in early infancy, food allergy can be related to the development of future asthma. For diagnosis, cut-off values are very important for both specific IgE levels and skin-prick test when interpreting food allergy. For the treatment, oral immunotherapy is showing promise for refractory patients with IgE-mediated food allergies. SUMMARY: Food allergies can be classified as IgE-mediated or non-IgE-mediated. Besides foods, some additives and preservatives can also trigger asthma in certain people. Asthma may develop in about 5% of individuals who suffer from food allergy and current asthma may be triggered by foods among 6-8% of children and 2% of adults. Because of the difficulty of confirming diagnosis of food allergy, novel approaches are currently being investigated and new therapy modalities are being sought. For total asthma control and for better quality of life, steps should be taken to avoid foods in cases of food allergy.     

Food allergy in gastroenterologic diseases： Review of literature

INTRODUCTION Food allergy is recognized as a common worldwide prob- lem, and, like other atopic disorders, its incidence seems to increase. Moreover, food-related allergic disorders are the leading cause of anaphylactic reactions treated in the emer- genc…     

Food allergy: a challenge for the clinician

Adverse reactions to food resulting in gastrointestinal symptoms and due to immunologic reactions (allergy) are discussed: their pathogenesis, the prevalence of food allergens and the clinical digestive expressions of food allergy in children and adults are reviewed. In IgE-mediated food allergy, the usefulness of the biological available tests is considered, mainly CAP tests, for proceeding to the diagnosis and the monitoring of the allergic disease. Finally, the best actual diagnostic tools in food allergy are considered (clinical history, skin tests, biological tests and food oral challenges), with their limitations and indications.     

Pearls and Pitfalls in Diagnosing IgE-Mediated Food Allergy

The term “food allergy” is used by many patients and clinicians to describe a range of symptoms that occur after ingestion of specific foods. However, not all symptoms occurring after food exposure are due to an allergic, or immunologic, response. It is important to properly evaluate and diagnose immunoglobulin E (IgE)-mediated food allergy as this results in reproducible, immediate onset, allergic reactions that can progress toward life-threatening anaphylaxis. Proper diagnosis requires understanding of the common foods that cause these reactions in addition to key historical elements such as symptoms, timing and duration of reaction, and risk factors that may predispose to development of IgE-mediated food allergy. Diagnostic testing for food-specific IgE can greatly aid the diagnosis. However, false-positive test results are very common and can lead to overinterpretation, misdiagnosis, and unnecessary dietary elimination. This review discusses important aspects to consider during evaluation of a patient for suspected IgE-mediated food allergy.     

Phenotypes of IgE-mediated food allergy in Turkish children

Data on food allergy-related comorbid diseases and the knowledge on factors associating specific food types with specific allergic outcomes are limited. The aim of this study was to determine the clinical spectrum of IgE-dependent food allergy and the specific food-related phenotypes in a group of children with IgE-mediated food allergy. Children diagnosed with IgE-mediated food allergy were included in a cross-sectional study. IgE-mediated food allergy was diagnosed in the presence of specific IgE or skin-prick test and a consistent and clear-cut history of food-related symptoms or positive open provocation test. Egg (57.8%), cow's milk (55.9%), hazelnut (21.9%), peanut (11.7%), walnut (7.6%), lentil (7.0%), wheat (5.7%), and beef (5.7%) were the most common food allergies in children with food allergy. The respiratory symptoms and pollen sensitization were more frequent in children with isolated tree nuts-peanut allergy compared with those with egg or milk allergy (p < 0.001); whereas atopic dermatitis was more frequent in children with isolated egg allergy compared with those with isolated cow's milk and tree nuts-peanut allergy (p < 0.001). Children with food allergy were 3.1 (p = 0.003) and 2.3 (p = 0.003) times more likely to have asthma in the presence of allergic rhinitis and tree nuts-peanut allergy, respectively. Interestingly, children with atopic dermatitis were 0.5 (p = 0.005) times less likely to have asthma. Asthma (odds ratio [OR], 2.3; p = 0.002) and having multiple food allergies (OR, 5.4; p < 0.001) were significant risk factors for anaphylaxis. The phenotypes of IgE-mediated food allergy are highly heterogeneous and some clinical phenotypes may be associated with the specific type of food and the number of food allergies.     

Hidden fish substance triggers allergy.

Food allergy (hypersensitivity) is a form of adverse food reaction caused by an immunological response to a particular food. IgE-mediated food allergy is responsible for most immediate-type food-induced hypersensitivity reactions. The prevalence of food allergy in the general population, not including oral allergy syndrome, is about 1-2%. While adults might tend to be allergic to fish, crustaceans, peanuts, and tree nuts, children, on the other hand, tend to be allergic to cow's milk, egg white, wheat, and soy. Food is the most common eliciting factor of anaphylaxis (45%), followed by drugs (29%), and insect stings (21%). Our study describes a 3 1/2-year-old boy who is allergic to fish consumed via ingestion and inhalation. This case is a good example of how easily people with food allergies can unintentionally consume foods to which they allergic, and is a clear demonstration of the dangers of such effects.     

Allergie à la farine de blé chez l’adulte

The clinical manifestations of allergy to wheat flour are similar to those of allergies to other foods. In adults, food-dependent exercise-induced anaphylaxis, chronic urticaria, and gastrointestinal food allergies (that is, irritable bowel syndrome, eosinophilic colitis, ulcerative colitis) are the most frequently described clinical manifestations of allergy to wheat. Wheat isolates, used as binders and emulsifiers in the food industry, are neo-allergens resulting from chemically induced desamidation of wheat gluten (heating at high temperature in an acidic medium). Wheat isolate allergens can induce severe systemic reactions (e.g., urticaria) and anaphylactic shock. Diagnosis consists of three steps: a suspicion based on the patient's history, identification of the allergen by skin testing and by laboratory tests, and confirmation by oral challenge or by an avoidance regime.     

Meeting the nutritional needs of the low-birth-weight infant

Approximately 5% of young children and 3-4% of adults exhibit adverse immune responses to foods in westernized countries, with a tendency to increase. The pathophysiology of food allergy (FA) relies on immune reactions triggered by epitopes, i.e. small amino-acid sequences able to bind to antibodies or cells. Some food allergens share specific physicochemical characteristics that allow them to resist digestion, thus enhancing allergenicity. These allergens encounter specialized dendritic cell populations in the gut, which leads to T-cell priming. In case of IgE-mediated allergy, this process triggers the production of allergen-specific IgE by B cells. Tissue-resident reactive cells, including mast cells, then bind IgE, and allergic reactions are elicited when these cells, with adjacent IgE molecules bound to their surface, are re-exposed to allergen. Allergic reactions occurring in the absence of detectable IgE are labeled non-IgE mediated. The abrogation of oral tolerance which leads to FA is likely favored by genetic disposition and environmental factors (e.g. increased hygiene or enhanced allergenicity of some foods). For an accurate diagnosis, complete medical history, laboratory tests and, in most cases, an oral food challenge are needed. Noticeably, the detection of food-specific IgE (sensitization) does not necessarily indicate clinical allergy. Novel diagnostic methods currently under study focus on the immune responses to specific food proteins or epitopes of specific proteins. Food-induced allergic reactions represent a large array of symptoms involving the skin and gastrointestinal and respiratory systems. They can be attributed to IgE-mediated and non-IgE-mediated (cellular) mechanisms and thus differ in their nature, severity and outcome. Outcome also differs according to allergens.     

Gibberellin-regulated protein allergy: Clinical features and cross-reactivity

Gibberellin-regulated proteins (GRPs)/GASA proteins are members of cysteine-rich antimicrobial peptide families and are conserved in a broad range of plants. Some GRPs in fruits and pollens have been identified as allergens including peach Pru p 7, Japanese apricot Pru m 7, orange Cit s 7, pomegranate Pun g 7, and cypress pollen GRP. The clinical features of fruit-derived GRP allergies frequently include systemic reactions, multiple fruit allergies regardless of plant kingdom classifications and, less frequently, cofactor-dependence. Multiple fruit allergies might be related to cross-reactivity between GRPs. Clinical cross-reactivity, at least between the four fruit-derived GRPs, has been proven. In addition, GRP allergy induces peculiar clinical symptoms, such as laryngeal tightness and facial swelling, especially eyelid edema, which was proposed to be a predictive factor for Pru p 7 allergy. Fruit-derived GRPs have an unusually high content of cysteine, resulting in high stability to heat and resistance to digestive enzymes. Therefore, GRPs are considered “true” food allergens that induce severe allergic reactions. As an alternative mechanism of fruit-derived GRP allergies, cross-reactivity between fruit GRP and cypress pollen GRP, which might play a role as a sensitizer, is suspected. Taken together, these characteristics indicate GRPs are clinically relevant plant allergens.This review article summarizes our current knowledge of the clinical features and important aspects of GRP sensitization and allergy.     

Définitions des termes utilisés en allergologie alimentaire chez l’enfant

In so far as there are no recent medical references that specify terms used in allergy, and particularly terms dealing with food allergy, it seemed to us that it would be of use to compile a glossary that would be helpful in daily practice. The defined terms (plus comments) have been retained according to sequences that correspond to steps in a food allergy work-up. The following terms are entered successively in this review: atopic dermatitis; SCORAD; asthma; pulmonary function tests; medications for children; symptoms and severity of food allergies; immediate skin tests; intradermal tests or “atopy patch-tests”; allergen-specific and total serum IgE levels; oral provocation test; labial provocation test; other tests used in allergy work-ups; allergy, hypersensitivity, atopy; allergens, allergies, sensitizations, allergic cross-reactions; treatment of an allergic reaction.     

Management of the Patient with Multiple Food Allergies

Food allergies affect 6% of children and 3% to 4% of adults in the United States. Although several studies have examined the prevalence of food allergy, little information is available regarding the prevalence of multiple food allergies. Estimates of prevalence of people allergic to multiple foods is difficult to ascertain because those with allergy to one food may avoid additional foods for concerns related to cross-reactivity, positive tests, or prior reactions, or they may be reluctant to introduce foods known to be common allergens. Diagnosis relies on an accurate history and selective IgE testing. It is important to understand the limitations of the available tests and the role of cross-reactivity between allergens. Allergen avoidance and readily accessible emergency medications are the cornerstones of management. In addition, a multidisciplinary approach to management of individuals with multiple food allergies may be needed, as avoidance of several food groups can have nutritional, developmental, and psychosocial consequences.     

Allergen Component Testing for Food Allergy: Ready for Prime Time?

Food allergies can cause life-threatening reactions and greatly influence quality of life. Accurate diagnosis of food allergies is important to avoid serious allergic reactions and prevent unnecessary dietary restrictions, but can be difficult. Skin prick testing (SPT) and serum food-specific IgE (sIgE) levels are extremely sensitive testing options, but positive test results to tolerated foods are not uncommon. Allergen component-resolved diagnostics (CRD) have the potential to provide a more accurate assessment in diagnosing food allergies. Recently, a number of studies have demonstrated that CRD may improve the specificity of allergy testing to a variety of foods including peanut, milk, and egg. While it may be a helpful adjunct to current diagnostic testing, CRD is not ready to replace existing methods of allergy testing, as it not as sensitive, is not widely available, and evaluations of component testing for a number of major food allergens are lacking.     

Latex-fruit syndrome

During the last decade, latex IgE-mediated allergy has been recognized as a very important medical problem. At the same time, many studies have dealt with allergic cross-reactions between aeroallergens and foods. In this context, there is clear evidence now on the existence of significant clinical association between latex and fruit allergies. Therefore, a latex-fruit syndrome has been postulated.Several studies have demonstrated that from 20% to 60% of latex-allergic patients show IgE-mediated reactions to a wide variety of foods, mainly fruits. Although implicated foods vary among the studies, banana, avocado, chestnut and kiwi are the most frequently involved. Clinical manifestations of these reactions may vary from oral allergy syndrome to severe anaphylactic reactions, which are not uncommon, thus remarking the clinical relevance of this syndrome.The diagnosis of food hypersensitivities associated to latex allergy is based on the clinical history of immediate adverse reactions, suggestive of an IgE-mediated sensitivity. Prick by prick test with the fresh foods implicated in the reactions shows an 80% concordance with the clinical diagnosis, and therefore it seems to be the best diagnostic test available nowadays in order to confirm the suspicion of latex-fruit allergy. Once the diagnosis is achieved, a diet free of the offending fruits is mandatory.Recently, some of the common allergens responsible for the cross-reactions among latex and the fruits most commonly implicated in the syndrome have been identified. Class I chitinases, with an N-terminal hevein like domain, which cross-react with the major latex allergen hevein, seem to be the panallergens responsible for the latex-fruit syndrome.     

Etiologic implication of foods in atopic dermatitis: evidence against

Atopic dermatitis is a typical chronic inflammatory skin disease that usually occurs in individuals with a personal or family history of atopy. Children with atopic dermatitis frequently present IgE-mediated food sensitization, the most commonly involved foods being egg and cow's milk. However, controversy currently surrounds whether food allergy is an etiological factor in atopic dermatitis or whether it is simply an associated factor, accompanying this disease as one more expression of the patient's atopic predisposition. Approximately 40 % of neonates and small children with moderate-to-severe atopic dermatitis present food allergy confirmed by double-blind provocation tests but this allergy does not seem to be the cause of dermatitis since in many cases onset occurs before the food responsible for allergic sensitization is introduced into the newborn's diet.Studies of double-blind provocation tests with food in patients with atopic dermatitis demonstrate mainly immediate reactions compatible with an IgE-mediated allergy. These reactions occur between 5 minutes and 2 hours and present mainly cutaneous symptoms (pruritus, erythema, morbilliform exanthema, wheals) and to a lesser extent, digestive manifestations (nausea, vomiting, abdominal pain, diarrhea), as well as respiratory symptoms (wheezing, nasal congestion, sneezing, coughing). However, these reactions do not indicate the development of dermatitis.Some authors believe that responses to the food in provocation tests may also be delayed, appearing mainly in the following 48 hours, and clinically manifested as exacerbation of dermatitis. However, delayed symptoms are difficult to diagnose and attributing these symptoms to a particular foodstuff may not be possible.Delayed reactions have been attributed to a non-IgE-mediated immunological mechanism and patch tests with food have been proposed for their diagnosis. In our experience and in that of other authors, the results of patch tests with cow's milk do not seem very specific and could be due, at least in part, to the irritant effect of these patches on the reactive skin of children with atopic dermatitis.The involvement of foods in atopic dermatitis will always be difficult to demonstrate given that an exclusion diet is not usually required for its resolution. Food is just one among several possible exacerbating factors and consequently identification of its precise role in the course of the disease is difficult. Further double-blind prospective studies are required to demonstrate the effectiveness of exclusion diets in the treatment of atopic dermatitis.Apart from the controversy surrounding the etiological role of foods, the most important point in atopic dermatitis is to understand that the child is atopic, that is, predisposed to developing sensitivity to environmental allergens; in the first few years of life to foods and subsequently to aeroallergens. Consequently, possible allergic sensitization to foods should be evaluated in children with atopic dermatitis to avoid allergic reactions and to prevent the possible development of allergic respiratory disease later in life.     

Position document: IgE-mediated allergy to egg protein

Egg is the food that most often causes allergy in young Spanish children, with an incidence of 2.4–2.6% in the first 2 years of life. The prevalence of sensitisation and allergy to egg is greater in children with allergy to cow's milk and in those suffering atopic dermatitis. The protein component from egg white is the cause of the allergic response in child. The major allergens in egg white are ovomucoid and ovalbumin. Most of the allergic reactions affect the skin, followed by gastrointestinal and respiratory systems. Egg allergy is one of the most common causes of severe anaphylaxis. The diagnosis of egg allergy is based on the existence of a suggestive clinical history, a positive allergy study and the subsequent application of controlled exposure testing, which represents the gold standard for confirming the diagnosis.The treatment of egg allergy is based on the avoidance of egg protein intake. A subgroup of egg-allergic patients are tolerant to cooked egg. In these cases, only uncooked egg must necessarily be avoided. Maintaining a diet with strict egg avoidance is difficult, and transgressions are relatively common. The patient, family, and school environment should receive education and training in the avoidance of egg and in the management of possible allergic reactions. With an avoidance diet, up to 15–20% of children will remain allergic and the severity of the reactions will increase over the years. In these more severe cases of egg-allergy, it becomes more difficult to adhere to the avoidance diet over the years, with a significant decrease in patient quality of life.Oral tolerance induction can be regarded as a therapeutic option for IgE-mediated egg allergy. The anti-IgE, omalizumab, might become another genuine therapeutic option for food allergy, not only to prevent allergic reactions after a contact with egg, but also as a complementary treatment to oral tolerance induction for egg allergy, with the purpose of reducing adverse reactions.The administration of influenza vaccine to children with egg allergy is safe in children that do not manifest severe reactions after egg intake, and in children who tolerate cooked egg. The triple viral vaccine (MMR) can be given to egg-allergic children in their usual vaccination centre, with no added risk. Different medicinal products can be formulated with egg proteins, and therefore should be avoided in children with egg allergy.     

Passive transfer of nut allergy after liver transplantation

An anaphylactic reaction to cashew nut developed in a nonatopic 60-year-old man 25 days after receiving a liver allograft from a 15-year-old atopic boy who died of anaphylaxis after peanut ingestion. The liver recipient had no history of nut allergy. Posttransplantation skin prick test results were positive for peanut, cashew nut, and sesame seed, and the donor had allergen-specific IgE antibodies to the same 3 allergens. Contact tracing of the recipients of other solid organs from the same donor disclosed no other development of allergic symptoms after ingestion of peanut or cashew nut. Results of molecular HLA typing did not detect any donor-origin leukocytes in the recipient after transplantation, which excluded peripheral microchimerism. The patient inadvertently ingested peanut-contaminated food and suffered a second anaphylactic reaction 32 weeks after the transplantation. This case illustrates that transfer of IgE-mediated hypersensitivity can occur after liver transplantation and have potentially serious consequences. We therefore recommend that organ donors undergo screening for allergies, and that recipients be advised regarding allergen avoidance.     

Facteurs de risque de l’allergie alimentaire sévère

Asthma is the main risk factor for severe, potentially fatal food allergy reactions. Peanut and tree nuts are the main foods involved in these reactions. Consequently, any asthmatic individual with a food allergy must be controlled perfectly by daily treatment. Other risk factors for severe allergic reactions are parallel medications (especially aspirin, beta-blockers and angiotensin enzyme inhibitors), physical effort, food consumption outside the home, mastocytosis, hidden allergens, and a combination of such associated factors. Better patient education and, in addition, risk prevention, particularly away from home, in restaurants and at school, should reduce the frequency of severe food allergic reactions. Collection of data concerning food allergies will allow better identification of the individuals at risk and development of targeted preventive measures.     

The risk of systemic reactions to skin prick-tests using food allergens: CICBAA data and literature review

Prick-tests to foods are usually carried out as the first step in the diagnosis of food allergy. Severe anaphylaxis accounts for 4.9 % of allergies in children and occurs more frequently in adults, raising the possibility of systemic reactions to prick-tests in highly sensitized people. Several studies published in the literature have used commercial extracts. As for airborne allergens, concentrations causing a skin reaction of 15 mm do not present a risk of systemic reactions. Prick-tests to native foods--prick-in-prick tests--have been less extensively studied. The CICBAA1 data, from 1,138 food allergic patients of all ages, cover 34,905 prick-in-prick tests to foods. The wheal of these prick-tests has been regulary registered. The risk of systemic reactions can be evaluated at 0.008 %. There were no severe reactions and anti-histamine and corticosteroid therapy were sufficient. These results are similar to those of the large study in 2000 carried out by Devenney in neonates (0.005%). A review of the literature reveals only a few severe reactions in adults. The authors draw attention to the necessary precautions: temporary contra-indication for skin prick-tests in children and adults with grade 3 or 4 asthma, with particular attention to such foods as all kinds of nuts, fish, etc.     

Overview of Component Resolved Diagnostics

Component-resolved diagnostics (CRD) utilize purified native or recombinant allergens to detect IgE sensitivity to individual allergen molecules and have become of growing importance in clinical investigation of IgE-mediated allergies. This overview updates current developments of CRD, including multiarray test systems. Cross-reactions between allergens of known allergen families (i.e. to Bet v 1 homologues) are emphasised. In pollinosis as well as in allergy to hymenoptera venoms or to food, CRD allows to some extent discrimination between clinically significant and irrelevant sIgE results and the establishing of sensitisation patterns with particular prognostic outcomes (i.e. sensitisations to storage proteins which correlate with clinically severe reactions in peanut allergy). Further promising improvements in diagnostics are expected from additional, not yet commercially available, recombinant allergen diagnostics identifying particular molecules of risk. Overall, CRD may decrease the need for provocation testing and may also improve the specificity of allergen-specific immunotherapy.