Hypersensitivity pneumonitis and related conditions in the work environment.

Hypersensitivity pneumonitis can occur from a wide variety of occupational exposures. Although uncommon and difficult to recognize, through a detailed work exposure history, physical examination, radiography, pulmonary function studies, and selected laboratory studies using sera and bronchoalveolar lavage fluid, workers can be identified early to effect avoidance of the antigen and institute pharmacologic therapy, if necessary. A lung biopsy may be necessary to rule out other interstitial lung diseases. Despite the varied organic antigen triggers, the presentation is similar with acute, subacute, or chronic forms. Systemic corticosteroids are the only reliable pharmacologic treatment but do not alter the long-term outcome.