Hypersensitivity pneumonitis: clinical perspectives.

CONTEXT: The clinical course of hypersensitivity pneumonitis (HSP) is highly variable and its diagnosis clinically challenging.

OBJECTIVE: To provide a concise review of major clinical, radiographic, and laboratory findings that permits diagnosis of HSP from the standpoint of a clinician/pulmonologist.

DATA SOURCES: Review of major contemporary and historical literature in combination with the author's experience and viewpoints.

CONCLUSIONS: The approach to the diagnosis of HSP is multidisciplinary. For patients being evaluated for unexplained dyspnea and cough and an unknown interstitial disease process, the initial evaluation should include detailed environmental and occupational histories with ancillary testing such as serology, chest imaging, inhalation challenges, and bronchoalveolar lavage, as indicated. In uncertain cases, lung biopsy is recommended.