Classification of Interstitial Lung Disease

Idiopathic  causes

  • Idiopathic Pulmonary Fibrosis (IPF)
  • Idiopathic non-specific interstitial pneumonia (NSIP)
  • Sarcoidosis

Connective tissue and autoimmune disease

  • Systemic sclerosis
  • Rheumatoid arthritis
  • Systemic Lupus Erythematosis
  • Scleroderma
  • Polymyositis
  • Dermatomyositis

Occupational and environmental

  • Organic and inorganic dust
  • Gases and fumes
  • Radiation
  • Asbestos  - (exposure often many years before)
  • Allergens – in Hypersensitivity Pneumonitis (HP; also called Extrinsic Allergic Alveolitis, EAA) that may be seen with bird keepers and farmers. In some cases, a patient may have HP/ EAA, but the allergen is not known or identified.

Drug induced

  • Antiarrhythmics - in particular Amiodarone
  • Antibiotics – in particular Nitrofurantoin
  • Anticonvulsants
  • Chemotherapy
  • Methotrexate
  • Radiation therapy


  • Viral or bacterial


  • Familial pulmonary fibrosis –(rarely)