Food-Dependent Exercise-Induced Anaphylaxis
Although still a relatively rare condition Food-Dependent Exercise-Induced Anaphylaxis, along with other forms of anaphylaxis, is growing.
Food-dependent exercise-induced anaphylaxis (FDEIA) is a relatively rare condition and occurs only when an allergic person eats a food that contains an allergen to which he or she is hypersensitive and exercises within 3 to 4 hours after eating. Eating the same food alone, without exercise, does not cause them to react.
FDEIA is considered to be subtype of exercise-induced anaphylaxis, which causes asthma and wheezing, urticaria, and a drop in blood pressure following exercise. (1) Other symptoms may include angioedema or swelling, gastrointestinal symptoms, bronchial constriction or difficulty in breathing, and vascular collapse. (2)
In most cases, specific foods do not cause any problems when they are eaten, except when eating them is followed by exercise when they can cause anaphylaxis. This is called specific FDEIA. In other cases, EIA results from exercise following consumption of any meal, regardless of the food eaten (called nonspecific FDEIA).
In specific FDEIA, there is usually an IgE-mediated reaction; skin-prick tests are positive and IgE food-specific antibodies can be detected in the patient’s blood. (3) Serum histamine and tryptase levels are increased during attacks, suggesting the release of inflammatory mediators from mast cells induced by IgE-mediated degranulation. (4)
Incidence of FDEIA
There is very little data available about the frequency of FDEIA, but reports of incidents of the condition have increased over the past 20 years, possibly reflecting an increased popularity of exercise in the general population (5) as well as an increased awareness of the condition.
FDEIA seems to be twice as common in females than in males and is especially prevalent in individuals 25 to 35 years of age. Individuals experiencing this type of reaction typically have asthma and other allergic conditions. (7)
Foods Associated With FDEIA
Although any food may contribute to this form of anaphylaxis, foods that have been reported most frequently as triggers of FDEIA include wheat, shellfish, fruit, milk, celery, and fish. However, there appear to be national differences in the most common trigger foods. For example, European and Japanese reports indicate wheat to be the most common food involved (1), whereas wheat accounts for only 5% of cases in the United States, with shellfish being highest at 16%, followed by alcohol (11%); tomato (8%); cheese (8%); celery (7%); strawberries (5%), wheat (5%), peach (5%); and milk (4%). (8) See below for list of foods most commonly associated with FDEIA.
Allergens in Food Associated With FDEIA
A few recent studies have sought to identify the specific allergens in foods that trigger FDEIA. It seems that the relevant allergens in the foods FDEIA may be different from those that cause other forms of allergy, including anaphylaxis.
For example, soluble proteins in wheat have been identified as allergens in baker’s asthma, whereas insoluble proteins (gluten) are allergens for wheat-dependent exercise-induced anaphylaxis. (8) Meanwhile, wheat-gamma-gliadin appeared to be the allergen in two cases of wheat-associated exercise-induced anaphylaxis (WAEIA) (9), but wheat-omega-5-gliadin in four cases of WAEIA25 in separate Japanese studies. There is increasing evidence for the important role of omega-5-gliadin in WAEIA to the extent that the allergen is being suggested as a marker in the differential diagnosis of the condition. (9)
In addition to the native allergen, the ability of gluten to cause an allergic response seems to be increased during digestion in sufferers ffrom WAEIA. When the wheat is digested with pepsin, the antigenicity, or ability to cause an allergic response, of the gluten was increased, but it decreased when digested with trypsin. This suggests that the antigenicity of gluten is enhanced in the stomach and attenuated in the duodenum.
Based on these observations, it is hypothesized that exercise might induce an increase in mucosal absorption of food peptides, including pepsin-digested gluten, in the small intestine before trypsin in the duodenum has an opportunity to act on the protein. This situation would then result in an enhanced allergen entering the circulation and triggering IgE-mediated allergy in sensitised individuals. (10)
Mechanism Responsible for FDEIA
It has also been suggested that exercise might change the efficiency of absorption of the allergen as a result of changes in blood flow through the major vessels and organs. (13) A dysfunction of the autonomic nervous system and the ability of gastrin to increase cutaneous mast cell mediator release have also been hypothesized as contributing to the onset of symptoms. (13)
Diagnosis of FDEIA
The diagnosis of FDEIA is usually made on the basis of the individual’s history. Development of signs of anaphylaxis during exercise, often starting with urticaria (hives), pruritus (itching), and erythema (reddening) that may be followed by breathing difficulty, and/or digestive tract symptoms in a food-allergic individual suggests FDEIA. (13)
Some studies have attempted to identify individuals who are likely to develop FDEIA by determining their sensitisation to specific foods by allergen-specific IgE and skin tests and subjecting the test-positive individuals to treadmill stress tests. However, because other variables not included in the test protocols may be contributing to the development of symptoms, most studies have been only partially successful in predicting which food-allergic subjects are likely to develop anaphylaxis while exercising. (14)
Directives for People Who Exhibit Anaphylactic Reactions to Foods
The most important preventive measure is to take every precaution possible to avoid exposure to the anaphylaxis-inducing food. The first requirement for prevention is
After the injection of the adrenaline, it is extremely important that the person is taken to the hospital, even if the symptoms appear to be improving; it is sometimes a secondary phase of the response that can prove fatal. Specific instructions for the use of injectable adrenaline (epinephrine) should be obtained from the allergic person’s doctor or health care provider.
People most at risk for anaphylaxis include:
General Guidelines for Avoiding Food Allergens Associated With Anaphylaxis
Foods most frequently associated with FAEIA
1. Chong SU, Worm M, Zuberbier T. Role of adverse reactions to food in urticaria and exercise-induced anaphylaxis. Int Arch Allergy Immunol. 2002;129:19-26.
If you found this article interesting, you will find many more articles on anaphylaxis here, and reports of research into anaphylaxis here.