Chronic extrinsic allergic alveolitis in a family with idiopathic pulmonary fibrosis: the importance of histological diagnosis.

We report a patient who presented with progressive exertional dyspnoea, chronic cough and radiographic signs of interstitial lung disease. Since several of his family members were known to have familial idiopathic pulmonary fibrosis he was also suspected to suffer from this disease. After thorough investigation, including histological examination of lung biopsies obtained by thoracoscopy, a diagnosis of chronic extrinsic allergic alveolitis was made. Current knowledge of familial idiopathic pulmonary fibrosis is discussed. This case report underlines the importance of a histological diagnosis in interstitial lung disease.