Causes and classification of interstitial lung disease in adults
A classification of the major interstitial lung diseases (ILDs) in adults is shown in Classification of major interstitial lung diseases in adults.
The aetiology of ILDs is wide-ranging and may be associated with environmental and occupational exposures (eg smoking, drugs, radiation, asbestos), systemic autoimmune disease (eg systemic sclerosis, rheumatoid arthritis) and genetic disorders. A definite cause has not been identified in some ILDs (eg idiopathic pulmonary fibrosis, sarcoidosis).
Idiopathic interstitial pneumonias
- idiopathic pulmonary fibrosis
- idiopathic nonspecific interstitial pneumonia
- cryptogenic organising pneumonia
Multisystem disorders
- connective tissue disease
- sarcoidosis
- inflammatory bowel disease
Environmental or lifestyle exposures
- smoking-related interstitial lung disease (eg respiratory bronchiolitis–interstitial lung disease, Langerhans cell histiocytosis, desquamative interstitial pneumonia)
- hypersensitivity pneumonitis
- occupational lung disease (eg asbestosis, silicosis, coal worker’s pneumoconiosis, mixed dust pneumoconiosis)
- drug-induced interstitial lung disease (eg caused by amiodarone, leflunomide, methotrexate, nitrofurantoin, or some oncology and immunomodulatory drugs [NB1])
- radiation-induced interstitial lung disease
Genetic
- familial idiopathic pulmonary fibrosis
- short telomere syndromes
Other
- lymphangioleiomyomatosis
- pulmonary alveolar proteinosis
- eosinophilic pneumonia
NB1: A comprehensive list of drugs associated with interstitial lung disease is available on the Drug-induced Respiratory Disease website.