Background.  Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) have been reported to enhance the symptoms of wheat-dependent exercise-induced anaphylaxis (WDEIA). In contrast to many reports on WDEIA, there have been only a few reports of wheat-dependent aspirin-induced anaphylaxis not induced by the combination of wheat and exercise.

Methods.  Two patients with wheat-dependent anaphylaxis underwent provocation tests to clarify the cause of their symptoms. Skin-prick testing (SPT) was also performed with and without administration of aspirin. Specific IgE antibody to wheat, gluten, and ω-5 gliadin were examined.

Results.  In the provocation tests, anaphylactic reactions were not induced by wheat or aspirin alone or by the combination of wheat and exercise, but were induced by the combination of wheat and aspirin. An increase in the blood histamine level was detected after provocation in both patients. Pretreatment with aspirin enhanced the SPT reactions to wheat and gluten in both patients. Specific IgE antibodies to wheat and gluten were expressed in the serum of both patients, and specific ω-5 gliadin IgE antibody was detected in the serum of one patient.

Conclusions.  We present two cases of specific wheat-dependent anaphylaxis induced by aspirin but not by exercise. We suggest that pretreatment with aspirin under controlled conditions is useful to confirm the diagnosis of food allergy when a challenge test with food alone or with food and exercise fails to induce positive reactions.