The cause of the scarring in<unk>  may be known (less commonly) or unknown (more commonly). Since the medical term for conditions of unknown cause is "idiopathic", the clinical term for<unk>  of unknown cause is idiopathic pulmonary fibrosis (IPF). Examples of known causes of<unk>  include connective tissue diseases (primarily rheumatoid arthritis), drug toxicity, chronic hypersensitivity pneumonitis, asbestosis and Hermansky–Pudlak syndrome.
Usual interstitial pneumonia
Desquamative interstitial pneumonia
Lymphocytic interstitial pneumonia
Granulomatous–lymphocytic interstitial lung disease
Diffuse panbronchiolitis
Non-specific interstitial pneumonia
Cryptogenic organizing pneumonia
Pulmonary hyalinizing granuloma