Occupational sensitization to lupin in the workplace: Occupational asthma, rhinitis, and work-aggravated asthma

Background: Lupin is a legume. Its seed can be ground into flour and incorporated into food as a protein source. Cases of rhinitis, urticaria, and anaphylaxis from ingestion of lupin have been reported as well as asthma. Objective: To present a cross-sectional study of workers in a food processing company who were exposed to lupin and developed occupational allergy secondary to inhaling lupin products. Methods: Subjects were interviewed using a standardized questionnaire, including demographics and current and past symptoms. They underwent skin prick tests (SPTs) to common aeroallergens and lupin products, spirometry, and off-line exhaled nitric oxide measurement. Symptomatic subjects, sensitized to lupin on SPT, underwent methacholine bronchial provocation challenge. Those with bronchial hyperresponsiveness had specific bronchial provocation challenge to lupin. Results: A total of 53154 subjects completed testing (98%). Overall, 21% (11153) had positive SPT results to lupin. The lupin-sensitive group had a trend toward atopy (P = .06). Seven of 11 (64%) subjects in this group were symptomatic; all had rhinitis, and 2 had wheeze. Two subjects had positive methacholine challenges, and 1 had a positive specific bronchial provocation challenge to lupin with both an early-phase and a late-phase response. Conclusion: Allergy to inhaled lupin occurs in the workplace. A high sensitization rate on SPT was found, which correlated with symptoms. The clinical significance of cross-reactivity between legumes on SPT is unclear. Clinical implications: Sensitization to the legume, lupin, can occur from exposure at work and carries a high prevalence of clinical symptoms, which in some cases leads to occupational rhinitis and asthma.