Surveillance for occupational asthma.

Medical surveillance programs can be established either for identification of workers potentially at risk for developing occupational asthma or for early detection of occupational asthma so that appropriate interventions can be made to prevent further cases. The author describes several tests used for the early detection of occupational asthma. These include respiratory and allergic symptom questionnaires, cross-shift spirometry, serial measurement of peak expiratory flow rates and/or serial methacholine challenge, and serial skin or serum testing for specific sensitization. Available data suggest that medical surveillance programs for early case detection and removal of affected workers from further exposure can be effective in preventing persistent asthma.