Pitfalls in the diagnostics of wheat-dependent exercise-induced anaphylaxis

There is a substantial risk to miss the diagnosis of an allergic immediate-type reaction, if neurological or cardiovascular conditions or symptoms dominate during anaphylaxis, and milder but typical allergic symptoms like generalized urticaria and pruritus are ignored. We report on a 43-year-old patient who presented with a 2-year history of repeated syncope. One of these events had been associated with a seizure. Initially, the patient had regularly noticed malaise, itching, generalized urticaria, and flushing. Most of these events had occurred during physical activity. There had been an extensive neurological and medical work-up including repeated cerebral CT scans, a bone marrow biopsy, a coronary angiography, and the implantation of an event recorder. None of these procedures had led to a firm diagnosis. Since doctors had suspected convulsions or a syncope caused by cardiac arrhythmia, the patient had been banned from driving, which meant that he could no longer do his job. Finally, the patient presented himself to an allergist who identified specific IgE antibodies against omega-5 gliadin. Results of a skin test with a standard wheat flour extract were unsuspicious. An oral provocation test using wheat flour in combination with the co-factors acetylsalicylic acid, alcohol, and physical exercise caused a generalized urticaria. After abstinence from wheat and spelt flour, the patient subsequently remained free of symptoms and was able to return to his work. If a patient presents with a syncope in connection with urticaria, flush and/or angioedema, it is essential to include anaphylaxis into the differential diagnosis. Although omega-5 gliadin rarely triggers food allergies in adulthood, it can frequently cause specific allergic reactions previously misclassified as idiopathic anaphylaxis.