The necessity for dual food intake to provoke food-dependent exercise-induced anaphylaxis (FEIAn): a case report of FEIAn with simultaneous intake of wheat and umeboshi

Food-Dependent Exercise-Induced Anaphylaxis Caused by Carrots: A Case Report

Background: Most cases of food-dependent exercise-induced anaphylaxis (FDEIA) are caused by eating wheat or crustaceans. However, fruits or vegetables may rarely act as allergens for FDEIA. We report a rare case of FDEIA caused by eating carrots. Case Presentation: An 8-year-old boy developed an anaphylactic reaction while playing, after eating lunch that included cooked carrots. Serum carrot-specific immunoglobulin E level was 0.19 UA/mL. The prick-by-prick test for raw carrots was positive (wheal diameter: 4 mm). The patient developed urticaria after exercise provocation tests following ingestion of raw carrots. Carrot proteins were analyzed by 2-dimensional Western blotting to identify the causative allergens. Nine proteins were identified as candidate antigens at 21-66 kDa. Conclusions: Our patient presented with FDEIA symptoms after ingesting both raw and cooked carrots. Both raw and cooked carrots contain 9 proteins that may induce FDEIA.

Food-Dependent Exercise-Induced Wheals, Angioedema, and Anaphylaxis: A Systematic Review

BACKGROUND

Food-dependent exercise-induced wheals, angioedema, and anaphylaxis remain insufficiently characterized.

OBJECTIVE

We systematically reviewed the literature on clinical manifestations, laboratory investigations, culprit foods, triggering exercise, comorbidities, and treatment outcomes.

METHODS

Using predefined search terms and Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) recommendations, we searched 3 electronic databases to identify relevant literature published before July 2021.

RESULTS

Of 722 patients (median age 25 years; 55.4% male) from 231 studies (43 cohort studies, 15 cases series, and 173 case reports), 79.6% and 3.7% had anaphylaxis with and without wheals and/or angioedema, respectively. The remaining 16.6% had wheals and/or angioedema without anaphylaxis. The duration from eating to exercising and from exercising to symptom onset ranged from 5 minutes to 6 hours (median 1 hour) and from 5 minutes to 5 hours (median 30 minutes), respectively, and virtually all patients exercised within 4 hours after eating and developed symptoms within 1 hour after exercising. Wheat was the most common culprit food. Running was the most common trigger exercise. Most patients were atopic, and 1 in 3 had a history of urticaria. Aspirin and wheat-based products were the most frequent augmenting factors. On-demand antihistamines, corticosteroids, and epinephrine were commonly used and reported to be effective. Patients who stopped eating culprit foods before exercise no longer developed food-dependent exercise-induced allergic reactions.

CONCLUSIONS

Food-dependent exercise-induced allergic reactions are heterogeneous in their clinical manifestations, triggers, and response to treatment. Patients benefit from avoidance of culprit foods before exercise, which highlights the need for allergological diagnostic workup and guidance.

Diagnosis and prevention of food-dependent exercise-induced anaphylaxis

Introduction: Food-dependent, exercise-induced anaphylaxis (FDEIA) is a rare type of anaphylaxis with a growing incidence. Although the precise mechanism by which the patient reacts only in a combination of a culprit food and cofactors are not currently understood, many advances in diagnosis and management have been made since their first description. Areas covered: A literature search in PubMed was performed to review the diagnosis and management of FDEIA. Clinicians should have a high level of suspicion for identification of the culprit foods and the cofactors involved. Component-resolved diagnosis and more accurate provocation tests have revolutionized the diagnosis accuracy. Management is not easy and involves educating the patient to evict the combination of exposure to the culprit foods and the cofactors that elicit anaphylaxis, and how to act and treat if a reaction occurs. Expert opinion: FDEIA is currently misdiagnosed and the authors believe that there are many FDEIA patients labelled as idiopathic anaphylaxis with unnecessary evictions and with a poor quality of life because of the fear of an imminent reaction. Due to recent advances in diagnostic tools and the use of monoclonal antibodies for prophylaxis in persistent cases, FDEIA can have a better prognosis improving the quality of life of the patients and their families.

How to manage food dependent exercise induced anaphylaxis (FDEIA)

PURPOSE OF REVIEW

In recent years, the number of reports on food-dependent exercise-induced anaphylaxis (FDEIA) has been increasing. This review aims to describe the standard management of FDEIA including provocation tests and identify the issues that remain unclear.

RECENT FINDINGS

Provocation tests with aspirin for FDEIA enable us to confirm the definitive diagnosis and to make differential diagnosis. In some cases, FDEIA symptoms can be induced by aspirin and the causative food without exercise. Exercise may only be an augmenting factor of FDEIA, similar to aspirin or alcohol.

SUMMARY

The mechanisms of FDEIA development remain unclear. It has been suggested that in FDEIA, exercise lowers the threshold of a food allergy. Further research is needed to elucidate the mechanism of FDEIA and to establish strategies for effective disease management.

Food-Dependent, Exercise-Induced Anaphylaxis: Diagnosis and Management in the Outpatient Setting

Food-dependent, exercise-induced anaphylaxis is a disorder in which anaphylaxis develops most predictably during exercise, when exercise takes place within a few hours of ingesting a specific food. IgE to that food should be demonstrable. It is the combination of the food and exercise that precipitates attacks, whereas the food and exercise are each tolerated independently. Recently, it was demonstrated that exercise is not essential for the development of symptoms, and that if enough of the culprit food is ingested, often with additional augmentation factors, such as alcohol or acetylsalicylic acid, symptoms can be induced at rest in the challenge setting. Thus, food-dependent, exercise-induced anaphylaxis appears to be more correctly characterized as a food allergy syndrome in which symptoms develop only in the presence of various augmentation factors, with exercise being the primary one. However, additional factors are not usually present when the patient exercises normally, so ongoing investigation is needed into the physiologic and cellular changes that occur during exercise to facilitate food-induced anaphylaxis.

Gibberellin-regulated protein in Japanese apricot is an allergen cross-reactive to Pru p 7

Background

Gibberellin‐regulated protein (GRP, also known as peamaclein) was recently identified as a new marker allergen related to systemic reactions in peach allergy; however, its role in other fruit allergies is unknown.

Objective

To investigate the allergenicity of Japanese apricot (JA) GRP and clarify the clinical characteristics of JA allergy patients with GRP sensitization.

Methods

Seven patients (two males, five females, mean age 28.0 years) diagnosed with JA allergy based on relevant clinical history, positive skin test and/or challenge test were enrolled. JA GRP with a molecular weight of 6896.5 Da was purified by ion‐exchange column chromatography. We performed enzyme‐linked immunosorbent assay (ELISA), IgE‐immunoblotting, basophil activating tests (BATs), and skin prick tests (SPTs) with purified JA GRP. To investigate the cross‐reactivity between JA GRP and native Pru p 7 (nPru p 7), we performed ELISA inhibition tests. We measured specific IgE levels against apricot, peach, rPru p 1, rPru p 3, and rPru p 4 using ImmunoCAP.

Results

ELISA and IgE‐immunoblotting using JA GRP showed positive reactions in six (85.7%) and seven (100%) patients, respectively. Five patients who provided informed consent for BATs and SPTs using JA GRP had positive results. In four patients who underwent ELISA inhibition tests using JA GRP and nPru p 7, IgE binding to one GRP inhibited binding to the other. The positivity for specific IgE against apricot, peach, rPru p 1, rPru p 3, and rPru p 4 was 14.3%, 57.1%, 0%, 0%, and 0%, respectively. Patients developed allergic reactions that were frequently accompanied with facial swelling, especially of the eyelids, which was dependent on cofactors, such as exercise.

Conclusions and Clinical Relevance

These results indicated that GRP might be a causative allergen of JA allergy, whose onset frequently requires a cofactor, such as exercise, and might be cross‐reactive between JAs and peaches.

Diagnosis of exercise-induced anaphylaxis: current insights

Exercise-induced anaphylaxis (EIAn) is defined as the occurrence of anaphylactic symptoms (skin, respiratory, gastrointestinal, and cardiovascular symptoms) after physical activity. In about a third of cases, cofactors, such as food intake, temperature (warm or cold), and drugs (especially nonsteroidal anti-inflammatory drugs) can be identified. When the associated cofactor is food ingestion, the correct diagnosis is food-dependent EIAn (FDEIAn). The literature describes numerous reports of FDEIAn after intake of very different foods, from vegetables and nuts to meats and seafood. One of the best-characterized types of FDEIAn is that due to ω5-gliadin of wheat, though cases of FDEIAn after wheat ingestion by sensitization to wheat lipid transfer protien (LTP) are described. Some pathophysiological mechanisms underlying EIAn have been hypothesized, such as increase/alteration in gastrointestinal permeability, alteration of tissue transglutaminase promoting IgE cross-linking, enhanced expression of cytokines, redistribution of blood during physical exercise leading to altered mast-cell degranulation, and also changes in the acid–base balance. Nevertheless, until now, none of these hypotheses has been validated. The diagnosis of EIAn and FDEIAn is achieved by means of a challenge, with physical exercise alone for EIAn, and with the assumption of the suspected food followed by physical exercise for FDEIAn; in cases of doubtful results, a double-blind placebo-controlled combined food–exercise challenge should be performed. The prevention of this particular kind of anaphylaxis is the avoidance of the specific trigger, ie, physical exercise for EIAn, the assumption of the culprit food before exercise for FDEIAn, and in general the avoidance of the recognized cofactors. Patients must be supplied with an epinephrine autoinjector, as epinephrine has been clearly recognized as the first-line intervention for anaphylaxis.

Provocation tests for the diagnosis of food-dependent exercise-induced anaphylaxis

BACKGROUND

Little has been reported regarding provocation tests for the diagnosis of food-dependent exercise-induced anaphylaxis (FDEIA), especially in children and adolescents. Hence, we here aimed to examine the usefulness and safety of such tests for FDEIA.

METHODS

We retrospectively analyzed 41 patients with 184 provocation tests. The patients underwent ergometer stress tests after ingesting the suspected foods along with aspirin. When one or more allergic symptoms appeared, we judged the provocation test as positive.

RESULTS

Based on 30 positive test results (16%), we diagnosed 20 patients (49%) as FDEIA. The major causative foods were as follows: wheat alone (five patients), combination of wheat and shrimp (three patients), combination of wheat and apple (two patients), and peach alone (two patients). The symptoms appeared within 45 min after initiating exercise in 29 tests (97%). The most frequent symptoms were cutaneous symptoms, which appeared in 25 tests (83%). Of the 30 positive tests, 6 (20%) required administration of adrenaline. After discharge, the patients with negative test results had no episodes of FDEIA due to the suspected foods that they had been tested for.

CONCLUSION

Provocation tests enabled us to confirm the diagnosis of FDEIA when positive and to exclude the diagnosis when negative. However, as severe symptoms may appear, these tests should be performed in a hospital under constant supervision of a physician.

Wheat allergy: diagnosis and management

Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.

Elicitors and co-factors in food-induced anaphylaxis in adults

Food-induced anaphylaxis (FIA) in adults is often insufficiently diagnosed. One reason is related to the presence of co-factors like exercise, alcohol, additives and non-steroidal anti-inflammatory drugs. The objective of this analysis was to retrospectively investigate the role of co-factors in patients with FIA. 93 adult patients with suspected FIA underwent double-blind, placebo-controlled food challenges with suspected allergens and co-factors.

The elicitors of anaphylaxis were identified in 44/93 patients. 27 patients reacted to food allergens upon challenge, 15 patients reacted only when a co-factor was co-exposed with the allergen. The most common identified allergens were celery (n = 7), soy, wheat (n = 4 each) and lupine (n = 3). Among the co-factors food additives (n = 8) and physical exercise (n = 6) were most frequent. In 10 patients more than one co-factor and/or more than one food allergen was necessary to elicit a positive reaction.

The implementation of co-factors into the challenge protocol increases the identification rate of elicitors in adult food anaphylactic patients.

Oral food challenge to wheat: a near-fatal anaphylaxis and review of 93 food challenges in children

Background

Wheat allergy is among the most common food allergy in children, but few publications are available assessing the risk of anaphylaxis due to wheat.

Methods

In this study, we report the case of near-fatal anaphylaxis to wheat in a patient undergoing an oral food challenge (OFC) after the ingestion of a low dose (256 mg) of wheat. Moreover, for the first time, we analyzed the risk of anaphylaxis during an OFC to wheat in 93 children, compared to other more commonly challenged foods such as milk, egg, peanuts, and soy in more than 1000 patients.

Results

This study, which includes a large number of OFCs to wheat, shows that wheat is an independent risk factor that is associated with anaphylaxis requiring epinephrine administration (Odds Ratio [OR] = 2.4) and anaphylaxis requiring epinephrine administration to low dose antigen (OR = 8.02). Other risk factors for anaphylaxis, anaphylaxis requiring epinephrine administration, and anaphylaxis to low dose antigen was a history of a prior reaction not involving only the skin (OR = 1.8, 1.9 and 1.8 respectively). None of the clinical variables available prior to performing the OFC could predict which children among those undergoing OFCs to wheat would develop anaphylaxis or anaphylaxis for low dose antigen.

Conclusion

This study shows that wheat is an independent risk factor that is associated with anaphylaxis requiring epinephrine administration and anaphylaxis requiring epinephrine administration to low dose antigen.

Exercise-induced anaphylaxis: A clinical view

Exercise-induced anaphylaxis (EIA) is a distinct form of physical allergy. The development of anaphylaxis during exertion often requires the concomitant exposure to triggering factors such as intake of foods (food dependent exercise-induced anaphylaxis) or drugs prior to exercise, extreme environmental conditions. EIA is a rare, but serious disorder, which is often undetected or inadequately treated. This article summarizes current evidences on pathophysiology, diagnosis and management. We reviewed recent advances in factors triggering the release of mediators from mast cells which seems to play a pathogenetic role. A correct diagnosis is essential to avoid unnecessary restricted diet, to allow physical activity in subjects with EIA dependent from triggering factors such as food, and to manage attacks. An algorithm for diagnosing EIA based on medical history, IgE tests and exercise challenge test has been provided. In the long-term management of EIA, there is a need for educating patients and care-givers to avoid exposure to precipitating factors and to recognize and treat episodes. Future researches on existing questions are discussed.

Food-induced anaphylaxis

Food-induced anaphylaxis (FIA) is a serious allergic reaction that may cause death rapidly in otherwise healthy individuals. There is no universal agreement on its definition or criteria for diagnosis. Hospital admissions for FIA have more than doubled in the last decade. Food is one of the most common causes of anaphylaxis, with most surveys indicating that food-induced reactions account for 30% to 50% of cases. The most commonly implicated foods are peanut, tree nuts, milk, eggs, sesame seeds, fish, and shellfish. The only life-saving treatment for anaphylaxis is allergen avoidance, and epinephrine injection if an anaphylactic event occurs.

Provoking allergens and treatment of anaphylaxis in children and adolescents--data from the anaphylaxis registry of German-speaking countries

Anaphylaxis is the most severe reaction of an IgE-mediated hypersensitivity. Data about affected patients may help to improve our knowledge of anaphylaxis and its medical care. We analysed data from the anaphylaxis registry of German speaking countries with regard to the provoking allergens and treatment modalities of anaphylaxis in children and adolescents. Inclusion criteria were severe systemic allergic reactions with concomitant pulmonary and/or cardiovascular symptoms. The data are collected by a password-controlled online-questionnaire. For this analysis, data of 197 reported anaphylactic reactions from children and adolescents registered between 2006 and 2009 were included. The data show that within the registered cases the most frequently affected organ systems for children and adolescents were the skin (89%) and the respiratory tract (87%) followed by symptoms of the cardiovascular system (47%) and the gastrointestinal tract (43%). The most frequent elicitors were food allergens accounting for 58% of cases, followed by insect venom (24%) and drugs (8%). The most frequent food allergens were peanuts followed by tree nuts and animal related food products. In 18% aggravating factors such as physical exercise were noted by the clinicians. 26% of the analysed patients had experienced more than one reaction. The data regarding the emergency treatment show that antihistamines (87%) and corticosteroids (85%) were often used but that adrenaline was rarely used (22% of the registered cases). Taken together these data show that the analysis of anaphylaxis by registration of affected individuals can provide data about provoking allergens and treatment measures but also suggest the impact of aggravating factors on anaphylactic reactions. The under-represented usage of adrenaline indicates the need of educational measures for patients and their physicians.

Food-dependent exercise-induced anaphylaxis -importance of omega-5 gliadin and HMW-glutenin as causative antigens for wheat-dependent exercise-induced anaphylaxis-

Food-dependent exercise-induced anaphylaxis (FDEIA) is a special form of food allergy where a food-intake alone does not induce any symptoms. However, allergic symptoms are elicited when triggering factors such as exercise or aspirin-intake are added after ingestion of the causative food. The most frequent causative foodstuff in Japan is wheat. The triggering factors, both exercise and aspirin-intake, facilitate allergen absorption from the gastrointestinal tract, resulting in allergic symptoms in the patients with wheat-dependent exercise-induced anaphylaxis (WDEIA). Analysis using purified wheat proteins revealed that approximately 80% of the patients with WDEIA have IgE reacting to omega-5 gliadin and the remaining of the patients to high molecular weight glutenin (HMW-glutenin). Simultaneous measurement of specific IgE to omega-5 gliadin and HMW-glutenin was found to be highly useful in diagnosing WDEIA compared with the routine diagnostic system for wheat.

Effect of oral sodium cromoglycate in 2 children with food-dependent exercise-induced anaphylaxis (FDEIA)

Food-dependent exercise-induced anaphylaxis (FDEIA) was prevented from recurring in 2 children by sodium cromoglycate (SCG) before intake of the causative food. CASE 1: A 14-year-old girl who had suffered recurrent symptoms of anaphylaxis when she exercised after lunch. Radioallergosorbent test (RAST) was 1.49 UA/mL for wheat. She was advised to take SCG before lunch. In 2007, she ate bread at lunchtime without taking SCG and developed anaphylaxis. After this, she always took SCG and did not develop anaphylaxis. CASE 2: A 9-year-old boy who had recurrent symptoms of anaphylaxis when he exercised after lunch. RAST was 0.46 UA/mL for wheat. He started taking SCG before lunch. In June 2008, he forgot to take SCG and ate fu (a food made from wheat). He exercised after lunch and developed anaphylaxis. Since then, he has always taken SCG and has not developed anaphylaxis.

CONCLUSION

Our findings suggest that SCG prevents FDEIA caused by wheat allergy.

Anaphylactic reactions on the beach: a cause for concern?

BACKGROUND

The commonest causes of anaphylaxis include hymenoptera bites, high-risk food, exercise, and jellyfish bites and may often be encountered on the beach. Therefore, millions of visitors at popular touristic locations are exposed to increased risk of anaphylactic reactions every year. At least 35 cases of acute allergic reactions requiring medical attention took place on the beaches of Crete, Greece during the previous summer.

OBJECTIVE

To evaluate the level of training of lifeguards working on the beaches of the island of Crete, Greece, with regard to emergency management of anaphylaxis as well as to assess the sufficiency of medical equipment that lifeguards possess to treat an anaphylactic reaction.

METHODS

A questionnaire was prepared by the authors and administered to 50 lifeguards working on various beaches of Crete. Queries included the definition of anaphylaxis, proper medical treatment, and the existence or not and composition of an emergency kit with regard to the management of acute allergic reactions.

RESULTS

Our series consisted of 50 lifeguards, 39 (78%) male and 11 female (22%). Although 41 (80%) lifeguards were aware of an acceptable definition of anaphylaxis, no one knew that epinephrine is the first-choice treatment, and 32 (60%) lifeguards replied that steroids should be used for emergency treatment. Additionally, no one possessed an emergency kit that would qualify for management of acute allergic reactions.

CONCLUSIONS

The beach should be considered as a high-risk place for the appearance of anaphylactic reactions. Lifeguards who would be the first trained personnel to encounter this condition should be sufficiently trained and equipped for emergency treatment. Our department is currently introducing a training program to local authorities for the proper training and equipping of lifeguards in the island of Crete.

Soybean beta-conglycinin as the main allergen in a patient with food-dependent exercise-induced anaphylaxis by tofu: food processing alters pepsin resistance

BACKGROUND

Food-dependent exercise-induced anaphylaxis (FDEIA) due to soybeans is a rare disorder. The allergen responsible for FDEIA due to soybeans has not yet been determined.

OBJECTIVE

We characterized the clinical features of a patient with FDEIA due to tofu, who was well tolerant to drinking soy milk. We then sought to identify the responsible soybean allergen(s) in that patient. We further studied whether different stabilities of the allergen(s) to pepsin digestion between two soybean products are related to their clinical allergenicity.

METHODS

Skin prick tests and provocation tests using soybean products were performed to detect the responsible food and other factors that induced the allergic symptoms. Specific IgE to various soybean allergens were examined by ImmunoCAP, ELISA and protein microarray assays. Immunoblotting for soybeans and soybean products using the patient's serum was also performed. Soybean products were serially digested by pepsin to disclose the stability of the allergens.

RESULTS

Provocation with ingestion of tofu and exercise induced the allergic symptoms, while ingestion of soy milk and exercise did not. Immunoblot analysis, ELISA and protein microarray assay revealed that beta-conglycinin mainly reacts with IgE antibodies in the patient's serum. By immunoblot analysis, beta-conglycinin in soy milk completely disappeared after pepsin digestion within 20 min, whereas beta-conglycinin in tofu was almost intact after more than 120 min of pepsin digestion.

CONCLUSION

We identified beta-conglycinin as the causative allergen in a patient with FDEIA induced by tofu. The difference in resistance to pepsin digestion between tofu and soy milk suggests that the presence of undigested allergens in the digestive tract is a prerequisite for the development of FDEIA.

Food-dependent exercise-induced anaphylaxis in childhood

The clinical syndrome of food-dependent exercise-induced anaphylaxis (FDEIA) is typified by the onset of anaphylaxis during (or soon after) exercise which was preceded by the ingestion of the causal food allergen/s. In FDEIA, both the food allergen/s and exercise are independently tolerated. FDEIA is an uncommon allergic condition in childhood, but nonetheless is an important differential diagnosis to be considered when faced by a child who has experienced exercise-associated anaphylaxis. The diagnosis of FDEIA is heavily dependent on the clinical history. Allergy tests may need to be performed to a broad panel of food and food additives. Modified exercise challenges (performed with and without prior ingestion of food) are frequently required as allergy test results frequently return low-positive results. A diagnosis of FDEIA facilitates the safe independent return to exercise and reintroduction of foods for patients who otherwise may unnecessarily avoid exercise and/or restrict their diet. The natural history of FDEIA is unknown; however, a safe return is usually achieved when the ingestion of the causal food allergen/s and exercise are separated.

Food-dependent exercise-induced anaphylaxis

Food-dependent exercise induced anaphylaxis (FDEIA) is a distinct form of food allergy induced by physical exercise. Symptoms are typically generalized urticaria and severe allergic reactions such as shock or hypotension. Whereas various food items are responsible for the development of FDEIA, wheat is reported to be the allergen with the highest frequency in Japan. Recently aspirin has been known to be an additional exacerbating factor. Skin tests and in vitro serum food-specific IgE assays are currently used, however their sensitivity and specificity are not always satisfactory. A challenge test consisting of ingestion of assumed food followed by intense physical exercise is the only reliable method to determine the causative food and to diagnose the disease. The challenge test is not always safe because in some cases the test induces an anaphylactic shock. So a reliable in vitro diagnostic method is necessary for the patients with FDEIA. We revealed that wheat omega-5 gliadin and high molecular weight glutenin subunit are major allergens in wheat-dependent exercise-induced anaphylaxis (WDEIA). A simultaneous detection of specific IgE to epitope sequences of both omega-5 gliadin and high molecular weight glutenin is found to achieve higher sensitivity and specificity compared with the in vitro serum food-specific IgE assays currently used for diagnosis of WDEIA. On the other hand, immunoreactive gliadins appeared in the sera of patients during the provocation test with both wheat-exercise and wheat-aspirin challenges in parallel with allergic symptoms. These findings suggest that FDEIA is IgE-mediated hypersensitivity reaction to foods and both exercise and aspirin facilitate allergen absorption from the gastrointestinal tract.

Food-dependent exercise-induced anaphylaxis with a high level of plasma noradrenaline

Ingesting certain foods sometimes triggers anaphylaxis when followed by exercise (food-dependent exercise-induced anaphylaxis, FDEIA). Specific food-induced mucocutaneous urticaria may also progress to anaphylaxis (oral allergy syndrome, OAS). A positive skin test and/or radioallergosorbent test (RAST) to the foods suggest involvement of immunoglobulin (Ig)E-anaphylaxis in both disorders. The triggering foods and initial target organs are usually different in each case. In the present study, a 32-year-old male reported dyspnea accompanied by wheals, and symptoms of low blood pressure while walking after eating Chinese noodles and donuts. He also reported uncomfortable sensations in his mouth and throat after ingesting melon. Exercise challenge tests were administered. Serum histamine, plasma adrenaline, noradrenaline and dopamine were measured pre- and post-test. No symptoms were induced by exercise or by the ingestion of any single food item before exercise. However, numerous wheals appeared when exercise followed the combined ingestion of foods. Likewise, the sequence of eating pancakes and then exercising resulted in numerous wheals and anaphylaxis. Olopatadine hydrochloride and ketotifen fumarate completely inhibited this anaphylaxis. The skin prick tests resulted in fruit-induced erythema and wheals. The results of these tests with wheat, butter and sugar were negative, and no symptoms were induced by the exercise test after ingestion of watermelon, melon or apple. The anaphylactoid symptoms were accompanied by a significant increase of plasma noradrenaline. In this case, not only wheat, but sugar and butter may induce the onset of FDEIA. There was no significant correlation between the intensity of the symptoms and the serum histamine levels in the present case. Noradrenaline may be involved in the onset of FDEIA, since noradrenaline may selectively inhibit T-helper (Th)1 functions while favoring Th2 responses. The tests showed no cross-reactivity between the causative foods of OAS and FDEIA, indicating that the mechanisms of onset are different between them.

Diagnosis of food allergy

BACKGROUND

Food allergy is gaining substantial interest by both the public and health professionals. It is usually overdiagnosed by the public and misdiagnosed by physicians.

OBJECTIVE

To provide an outline for appropriate evaluation of patients suspected of having food allergy.

DATA SOURCES

Information was derived from selected review and original articles published in peer-reviewed journals and from authoritative textbook chapters, supplemented by the clinical experience of the author.

RESULTS

Several approaches have been used for food allergy diagnosis, including the medical history, trials of elimination diets, food/symptom diary, skin testing, in vitro tests, and oral challenges. In most cases, the medical history is inconclusive and the reliability of the in vivo and in vitro tests is suboptimal. Appropriately designed challenge testing remains the gold standard, although it has a few limitations.

CONCLUSIONS

Appropriate selection, application, and interpretation of tests for food allergy are necessary for attaining a high degree of accuracy of diagnosis.

Clinical expressions of food allergy

BACKGROUND

The perception, by both the public and health professionals, of the clinical expressions of food allergy (FA) varies widely, from one extreme of nonexistence to another extreme of causing almost every ailment. Critical investigations in recent years led to a better clarification, as well as a reasonable classification, of FA manifestations.

OBJECTIVE

To provide a differential diagnosis of adverse reactions to foods and a classification of well proven FA manifestations.

DATA SOURCES

Reviews and original articles published in peer-reviewed journals, as well as classic textbooks on FA.

RESULTS

FA can affect several body systems. The gastro-intestinal tract is probably the most affected organ, but it does not always exhibit overt symptoms. Cutaneous manifestations are next in frequency, and in some studies are the most frequent perhaps because they are visible. Respiratory symptoms as sole manifestations of FA are less common, but have high frequency in children with atopic dermatitis. Systemic anaphylaxis has been responsible for sudden fatalities, although the exposure was often to minute quantities of the offending food. Other rare manifestations have been reported and are probably underdiagnosed.

CONCLUSIONS

FA is defined as the immunologically mediated adverse reactions to foods. It can be expressed in a wide array of clinical manifestations, ranging from simple gastro-intestinal, cutaneous, or respiratory symptoms to fatal anaphylaxis. Studies are needed to verify some rare or anecdotal manifestations that have been reported but are still considered controversial.

Food allergy diagnosis: are there any missing factors? A theoretical approach

Actual diagnostic criteria in food allergy frequently show a group of subjects with uncertain diagnosis, i.e., subjects with only occasional reactions to an offending food. These subjects are probably under- or misdiagnosed. It is possible that food itself may be only one of the factors involved in the allergic food reaction, at least in these subjects. In these cases, several factors besides food could modify either the allergenic potential of food or the absorption of allergens and may be relevant for a clinical response to occur. In order to investigate the possible relevance of missing factors, a theoretical model is elaborated by modifying the equation that represents the classical food allergy model: xAg+(IgE(*)-cell)--> clinical response (mediators release em leader ). In this classical model, it is assumed that if there is specific IgE against a food (IgE*-cell), the only limiting factor will be x (total amount of allergen ingested), being Ag, the allergen supposed to elicit a clinically relevant response. Always that x>/=a (threshold quantity of allergen that elicits a reaction) a reaction should occur. The possible existence of missing factors, i.e., the presence of 'modified allergens' (Ag('),Ag("), em leader,Ag(n)) induced by modification of the allergenic potential of food, are not considered in the equation, but these factors may have clinical relevance, and these relevance could be related to x(1),x(2), em leader,x(n) (relative quantities of 'modified allergens'). So, a modified formula is proposed:(x-Sigma(x(1),x(2), . . . x(n)]Ag+Sigma(x(1)Ag('),x(1)Ag("), . . . x(n)Ag(n)]+IgE(*)-cell)-->clinical response. In this formula, depending of the relative amount of the limiting factors: x(1),x(2), . . . x(n) and the relevant allergen (Ag,Ag('),Ag(") . . . or Ag(n)) to which the subject is sensitized an allergic reaction could or could not be elicited. So, factors other that the food itself and the threshold of sensitivity may be missed in the diagnosis of food allergy. When there are not any factors modifying Ag, the allergic response will depend only on the amount of x ('classical equation'). But when there is some kind of modification the response will depend on the relevance of the modified allergens and on the relative amount of them. If the factors modifying the allergenicity cannot be controlled, the amount of the clinically relevant allergen cannot be estimated, and the clinical response may be only occasional, explaining the inconsistent findings of some subjects.

Exercise-induced Anaphylaxis

Exercise-induced anaphylaxis has been recognized with increasing frequency since its original description in 1980. Recent studies suggest food-induced reactions may occur frequently in this syndrome, which is a mast cell-dependent phenomenon. In this article, the clinical manifestations of exercise-induced anaphylaxis are reviewed, and food-related factors contributing to the disorder are considered.

Role of adverse reactions to food in urticaria and exercise-induced anaphylaxis

In urticaria, adverse reactions to food are only a frequent finding in the subset of patients with chronic continuous urticaria. Mostly these reactions are of pseudoallergic nature, directed against artificial additives as well as naturally occurring aromatic components. IgE-mediated allergic reactions are a rare cause in acute urticaria as well as in recurrent chronic urticaria. In other types of urticaria, e.g. physical urticaria, food plays hardly any role as an eliciting agent with the exception of ice-cold drinks in cold urticaria. By contrast, exercise-induced anaphylaxis is frequently food-dependent. Two subtypes are distinguished: unspecific food-dependent exercise-induced anaphylaxis (FDEIA), where the filling of the stomach independently of the kind of food ingested prior to exercise is responsible for the symptoms. In specific FDEIA, an IgE-mediated food allergy causes symptoms only in combination with exercise. In the latter group, wheat is an important allergen.

Update on the clinical features of food-induced anaphylaxis

Food-induced anaphylaxis has become the leading cause of anaphylactic reactions that occur outside hospital. We introduce the present review with a definition of food-induced anaphylaxis, including its prevalence and proposed etiology. Second, we discuss an entity that is increasingly being recognized: exercise-induced food anaphylaxis, which may be triggered by specific foods or at times where no specific food has been identified. Third, we review current attempts to identify specific food antigens that are responsible for anaphylaxis to well-known triggers (i.e. peanut, as well as more unusual antigens). Fourth, we discuss current treatment options available (i.e. patient education, food avoidance, acute symptom recognition, and early use of self-administered epinephrine). Additionally, we discuss outcome data regarding the morbidity and mortality related to food allergy and anaphylaxis. Finally, information regarding experimental immunomodulatory therapy is presented.

Food-dependent exercise-induced anaphylaxis: influence of concurrent aspirin administration on skin testing and provocation

BACKGROUND

Provocation tests in patients with food-dependent exercise-induced anaphylaxis (FDEIA) are often negative, even after a sufficient quantity of the implicated food and exercise have been taken.

OBJECTIVES

To investigate the effect of aspirin in provocation tests and in skin prick testing (SPT) of patients with FDEIA. Gluten as a major allergen in wheat-dependent FDEIA was also investigated.

METHODS

Provocation tests and SPT with suspected foods were performed in 12 patients with FDEIA. Provocation tests were performed with combinations of foods, exercise and aspirin. Detection of gluten-specific IgE was also performed by the CAP System FEIA radioallergosorbent test, SPT and a histamine release test.

RESULTS

The SPT reaction was enhanced by pretreatment with oral aspirin in five of eight (62.5) patients. Aspirin facilitated provocation in five of seven (71%) patients tested. Ingestion of wheat and aspirin without exercise provoked symptoms in two patients. Aspirin provoked symptoms even with a small amount of wheat and exercise in one patient. Only the combination of aspirin, wheat and exercise provoked anaphylaxis in one patient. Specific IgE, SPT and/or the histamine release test with gluten were positive in nine of 11 patients with wheat-dependent FDEIA.

CONCLUSIONS

Aspirin enhances symptoms of FDEIA, and prior ingestion of aspirin under controlled conditions can be used to confirm FDEIA. In practice, such patients should avoid aspirin ingestion. Gluten appears to be the major allergen in these patients with wheat-dependent FDEIA.

Frequency of food-dependent, exercise-induced anaphylaxis in Japanese junior-high-school students

BACKGROUND

Food-dependent, exercise-induced anaphylaxis (FEIAn) is classified among the physical allergies. The pathophysiology of FEIAn remains unknown, as does the frequency of FEIAn in the general population.

OBJECTIVE

We sought to study the epidemiology of FEIAn, especially its frequency in junior-high-school students in Yokohama, Japan.

METHODS

A questionnaire asking about the occurrence of FEIAn in school students was sent to all 145 public junior-high-school nurses in Yokohama.

RESULTS

One hundred thirty-two junior-high-school nurses responded to the questionnaire, and 13 (11 boys and 2 girls) cases of FEIAn among 76,229 junior-high-school students were reported. In addition, 24 (12 boys and 12 girls) subjects with exercise-induced anaphylaxis (EIAn) were detected. From this survey, the frequency of FEIAn was 0.017% in this population, and its frequency was significantly higher in boys than in girls (P < .05). The frequency of EIAn was 0.031%, and there was no difference according to sex. Only one third of junior-high-school nurses had any knowledge of FEIAn. We also performed provocation tests in 5 of the 13 cases with FEIAn after obtaining informed consent from the students and their parents and were able to confirm the diagnosis.

CONCLUSION

This study showed that FEIAn and EIAn are relatively rare diseases among junior-high-school students in Yokohama. To avoid serious outcomes, we believe it is important that not only physicians but also school nurses and teachers of physical education be aware of these diseases.