Food-dependent exercise-induced anaphylaxis: a case related to the amount of food allergen ingested.

A 24-year-old Japanese woman had suffered for 2 years from attacks of urticaria, dyspnoea and syncope associated with exercise after the ingestion of wheat. Specific IgE measurements revealed RAST class 2 for wheat and gluten (a major wheat protein), and class 3 for rye. Skin prick tests with wheat, bread, gluten and udon (a Japanese noodle made of wheat) were all positive. Food-dependent exercise-induced anaphylaxis (FDEIA) caused by wheat was suspected. Challenge tests with bread were performed. Exercise following ingestion of 64 g, but not 45 g, of bread induced generalized urticaria. Challenge tests with udon also triggered allergic reaction in a dose-dependent manner: 200 g, but not 100 g or 150 g, of udon elicited wealing and erythema with exercise. Ingestion of bread or udon alone failed to elicit any allergic reaction. This is the first case of FDEIA in which the dependence of the triggering allergic reaction on the amount of allergen ingested was clearly confirmed.