We are able to identify more than 100 different forms of lung fibrosis. In general, they can be divided into forms with a known cause and those with an unknown cause. However, there are a few that occur particularly frequently. In Europe, these include sarcoidosis, the group of idiopathic interstitial pneumonias and extrinsic allergic alveolitis.

Sarcoidosis and extrinsic allergic alveolitis are caused by chronic inflammation. In most cases, complete reversal of the changes is possible in the early stage. This occurs either spontaneously (that is, without treatment) or on treatment with steroids (e.g. cortisone). The group of idiopathic interstitial pneumonias is more difficult to evaluate in terms of its course and prognosis. This group currently includes 7 different subforms which can be differentiated on the basis of clinical, imaging and histological criteria. Within this group, idiopathic pulmonary fibrosis (IPF) has special significance because of its incidence and aggressive course. IPF can occur either sporadically or in increased numbers in certain families. The causes have so far not been discovered. In the last few years, however, a large amount of evidence has been found to suggest that chronic damage to the lining cells (epithelium) of the alveoli is involved in the occurrence of the disease.

As mentioned above, there are more than a hundred causes of the development of interstitial lung disease. The following list therefore does not claim to be complete:

• Lung fibrosis as part of rheumatic-type diseases (collagen/vascular diseases)
  • - scleroderma
  • - rheumatoid arthritis
  • - mixed connective tissue disease
  • - polymyositis/dermatomyositis
  • - systemic lupus erythematosus
• Lung fibrosis triggered by medical treatments
  • - antibiotics (e.g. nitrofurantoin)
  • - anti-arrhythmics (e.g. amiodarone)
  • - anti-inflammatory drugs
  • - anticonvulsants
  • - chemotherapy agents (e.g. bleomycin)
  • - radiotherapy
  • - oxygen
• Lung fibrosis caused by inhaled dust particles
  • - inorganic dusts (asbestosis, silicosis [coal worker’s pneumoconiosis], talc pneumonia,)
  • - organic dusts (extrinsic allergic alveolitis)
• Lung fibrosis in association with systemic diseases of unknown origin
  • - sarcoidosis
  • - amyloidosis
  • - Niemann-Pick/Gaucher’s disease
  • - Hermansky-Pudlak syndrome
• Lung fibrosis of unknown origin
  • - idiopathic pulmonary fibrosis (IPF)
  • - non-specific interstitial pneumonia (NSIP)