Early detection of hypersensitivity pneumonitis in office workers.

Symptoms of hypersensitivity pneumonitis in three employees in an office building led to an investigation of their work environment. An open spray water air cooling system was implicated when inhalation challenge with the spray water caused acute illness in one of them. A questionnaire survey of the 4,023 co-workers identified 48 other suspect cases, and laboaratory studies confirmed hypersensitivity pneumonitis in three additional workers of this group. A significant change in pulmonary function, occurring only after exposure to the work environment, was the most useful laboratory finding and was found in five workers with no other pulmonary abnormalities, but not is asymptomatic workers or controls, since five of the six patients with hypersensitivy pneumonitis worked in offices cooled by the spray water system and since three had positive responses to inhalation challenge, use of the spray water system was discontinued. The affected workers improved after they were removed from the office complex.