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.