Occupational sensitization to lactase in the dietary supplement industry.

Aerogen lactase exposure carries a risk for the development of allergic asthma and rhinitis; only a few occupationally affected patients have been reported. The authors report the results of allergy testing with employees of a lactase tablets manufacturing plant. The survey involved 13 workers, including a questionnaire, spirometry, basophil activation test (BAT), and skin prick tests (SPTs) with lactase and a panel of common aeroallergens. Furthermore, lactase-specific immunoglobulin E (IgE) antibodies were analyzed. Sensitization to lactase could be proven for 9 workers by SPT and BAT; specific IgE antibodies could be detected in serum samples of all sensitized. However, IgE levels ≥0.35 kU/L were only found in 4 sera. These data confirm that occupational exposure to lactase can induce IgE-mediated respiratory sensitization resulting in allergic diseases. Protective measures should thus be obligatory when working with lactase.