Unknown | Idiopathic |
Infections | Haemophilus influenzae, Acinetobacter baumannii, Chlamydia, respiratory syncytial virus, influenza virus A/H1N1, human immunodeficiency virus, Pneumocystis jirovecii, and Penicillium citrinum |
Autoimmune diseases | Ankylosing spondylitis, antisynthetase syndrome, collagen vascular disease, fibromyalgia, juvenile dermatomyositis, dermatomyositis, polymyositis, primary biliary cirrhosis, very severe aplastic anemia, undifferentiated connective tissue diseases, systemic lupus erythematosus, necrotizing myopathy, and primary Sjögren’s syndrome |
Durgs | Abacavir, amiodarone, bleomycin, decitabine, everolimus, sirolimus, zacytidine |
Environmental exposures | Aerosols, asbestos, coal, dusts |
Others | Myelodysplastic syndrome, lung transplant, bone marrow transplant |