Occupational airborne contact urticaria, anaphylaxis and asthma in farmers and agronomists due to Bruchus pisorum.

Abstract

Occupational contact urticaria due to inhalation of legume pest allergens has rarely been described. To determine the cause of an outbreak of airborne contact urticaria, asthma, and anaphylaxis in farmers and agronomists studying the disinsectization of dried peas. Peas were treated with aluminum phosphide (EPA). Extracts prepared from Bruchus lentis and Bruchus pisorum bodies and from healthy legumes, EPA-treated legumes, and infested legumes, were used for in vivo tests (skin prick testing, oral, and specific bronchial challenge for the diagnosis of asthma and anaphylaxis) in affected patients and in five control patients with severe legume hypersensitivity. Open application, patch testing with the most common legume insecticides, molecular analysis, and IgE immunoblotting were undertaken. We found positive responses (prick, provocation, immune detection) to parasitic pea extracts and B. pisorum. A 25 kDa band was detected in the western blot of all patients who worked with infested EPA-treated peas. Bands from B. pisorum extract were detected in all patients. No responses to pea allergens were found in any patient, unlike in legume allergy controls. Oral provocation tests were negative. B. pisorum is a cause of contact urticaria and may cause occupational hives, anaphylaxis, and asthma. The allergen may enter by inhalation or puncture of setae released by B. pisorum.