Aims : To present state of the art decision algorithms, based on serologic testing, the pathogenesis of lung inflammation and the development of fibrosis, in the diagnosis (laboratory, radiology, pathology) and management of patients with chronic fibrotic hypersensitivity pneumonitis: to describe subtle radiological findings that differentiate this disease from other interstitial lung diseases, such as usual interstitial pneumonia; to evaluate the pathological diagnosis of chronic fibrotic hypersensitivity pneumonitis; and to assess the efficacy of anti-fibrotic and immunosuppressive agents.