Objectives This study attempted to develop and evaluate a challenge test for diagnosing allergic asthma and rhinitis due to cellulase.

Methods Challenge tests in a chamber were performed on 11 persons sensitized to cellulase. Four different enzyme-lactose mixtures, starting from a 0.03% mixture, were used. The enzyme dust was generated from a dry enzyme preparation mixed with lactose powder, using pressurized air. The cellulase concentration in the air was measured with an immunochemical method.

Results Nasal, pharyngeal, or bronchial symptoms could be elicited at cellulase air concentrations of 1 to 1300 mg/m3. A dose-response relationship was observed for symptoms in repeated challenge tests with increasing concentrations of cellulase. For 2 persons skin symptoms could also be reproduced. Conclusion The challenge method proved to be a practical means with which to simulate conditions at the worksite and elicit the specific respiratory symptoms of the patients.

Key terms chamber challenge; enzymes; occupational asthma; occupational rhinitis