Hypersensitivity pneumonitis.

The family physician should understand the features of hypersensitivity pneumonitis which is a potentially serious, even fatal disorder. It should be considered in the differential diagnosis of any patient with breathlessness, particularly if there is a history of a recurrent influenza-like illness or pneumonia. Prompt recognition and avoidance of contact with the offending antigen will avoid permanent disability. In Australia the avian antigens and exposure to dry rot are the most frequent documented causes.