Exercise-induced anaphylaxis: useful screening of food sensitization.

BACKGROUND AND OBJECTIVES: Exercise-induced anaphylaxis is a well-defined entity as described by Sheffer and Austen. Exercise-induced anaphylaxis can be associated with ingestion of a specific food. We report our experience with a series of cases of exercise-induced anaphylaxis in which anaphylaxis was considered to be associated with food allergy.

METHODS: We observed 19 patients in whom severe systemic signs of anaphylaxis occurred during or immediately after exercise, while the severity of reactions excluded challenge testing. The causal relationship with various foods was systematically investigated in all cases, even in the absence of any history of allergy.

RESULTS: Sensitization to wheat flour was demonstrated in 12 patients, to peanut in seven, and to tree nuts in six cases with skin tests and/or RAST. Sensitivity to various other foods was found less often. Further, avoidance of specific foods according to results of skin tests and RAST was systematically observed during the five hours prior to exercise and no symptom occurred, suggesting a role of specific food intake in the pathogenesis of exercise-induced anaphylaxis. With such elimination diets, most of these young patients were able to engage in regular vigorous exercises (more than twice a week in some cases) without any clinical manifestation with a median followup of 2 years. In two patients, however, recurrence of exercise-induced anaphylaxis was subsequently explained by concomitant ingestion of other foods such as rice and peanut. Additional avoidance of these foods before exercise was then effective in 14 cases (median follow up: 2 years).

CONCLUSIONS: Investigations to detect food sensitization, in particular to wheat, peanut and/or tree nuts, and specific avoidance of these foods five hours before exercise appear essential in cases of exercise-induced anaphylaxis.