Oilseed rape flour: another allergen causing occupational asthma among farmers

Background: Farmers are exposed to a wide variety of sensitizers. Since occ upational asthma (OA) can lead to permanent disability, exposure discontinu ation is the preferred treatment. When this is not possible, the identifica tion of the causative allergen may allow an alternative therapy. Methods: We present three farmers diagnosed with OA as a consequence of han dling fodder. We carried out skin tests with common and occupational allerg ens and with oilseed rape (OSR) extract. Total and specific serum IgE level s were measured. The patients underwent the OSR-bronchial provocation test (OSR-BPT). The day before and 24 h after the OSR-BPT, the methacholine (M)- BPT and induced sputum were performed. Eosinophil percentages and ECP level s were measured in the sputum samples. Results: OSR sensitization (skin tests and specific serum IgE) was detected in all the patients. The OSR-BPT elicited early responses in two subjects. Methacholine sensitivity, sputum eosinophils, and sputum ECP levels increa sed 24 h after the OSR-BPT in all the patients. Conclusions: We have demonstrated that inhalation of OSR flour causes bronc hoconstriction, induces an eosinophilic inflammatory bronchial response, an d increases bronchial hyperresponsiveness in sensitized asthmatics. OSR flo ur contained in animal fodder should be considered another potential cause of OA among farmers.