Noninfectious pulmonary diseases masquerading as community-acquired pneumonia.

A wide spectrum of pulmonary disorders may manifest clinical and radiographic features consistent with infectious pneumonitis. Bronchiolitis obliterans, eosinophilic pneumonia, hypersensitivity pneumonitis, pulmonary vasculitis, alveolar hemorrhage, and alveolar proteinosis all may be difficult to distinguish from community-acquired pneumonia. The salient clinical features of these disorders are reviewed in this article. In addition, specific diagnostic and therapeutic approaches that may aid in differentiating these unusual diseases from the pulmonary infections they mimic are outlined.