Primary pneumothorax | Asthenic body habitus/subpleural blebs | Drug use | Cigarette smoking | Snorting cocaine | Smoking marijuana | Increased transpulmonary pressure | Valsalva maneuver | Diving, military flying | | Secondary pneumothorax | Airway disease | Cystic fibrosis | Asthma | COPD | Infection | Pneumocystis jirovecii (carinii) | Tuberculosis | Necrotizing pneumonia | Congenital lung disease | Congenital pulmonary adenomatous malformation | Congenital lobar emphysema | Interstitial lung disease | Sarcoidosis | Langerhans cell granulomatosis | Other | Connective tissue/inflammatory disease | Marfan syndrome | Ehlers-Danlos syndrome | Juvenile idiopathic arthritis | Polymyositis or dermatomyositis | Birt-Hogg-Dubé syndrome | Other | Malignancy | Primary lung cancer | Metastatic disease | Airway obstruction | Foreign body aspiration | Thoracic endometriosis | Catamenial pneumothorax | |