Causes of Pulmonary Fibrosis 

Causes of PF

When the lung is injured the body responds by healing the wound.  Abnormal wound healing can lead to the development of excess scar tissue (fibrosis) and interstitial lung disease. 

A person's lungs are constantly exposed to the environment and are at risk for injury.  The lung has to respond to the dust, fumes, microbes, toxins and pollutants that are breathed in from the air. 

These agents in the environment cause minor injury to our lungs. During the healing process, scar tissue can develop.  Most of the time the lung heals normally and the amount of scarring is minimal.  If the healing process is abnormal an excessive amount of scar tissue can develop.  This is called fibrosis and can irreversibly damage the lung. 

Some of the agents that have been associated with the development of pulmonary fibrosis have been identified.  However, more often than not the reason a person develops pulmonary fibrosis is not known.  It is thought that genetic factors also play a role in the development of pulmonary fibrosis.  For more information about genetics and pulmonary fibrosis see the "genetics" section.  


Factors Associated with Pulmonary Fibrosis

There are many exposures or disease that are thought to contribute to the development of pulmonary fibrosis.  Listed below are several factors that are associated with pulmonary fibrosis.

Environmental or occupational exposures

  • Asbestos
  • Silica
  • Beryllium
  • Tungsten carbide
  • Bird droppings & dander
  • Molds

Related to Autoimmune diseases

  • Rheumatoid Arthritis
  • Lupus
  • Scleroderma
  • Polymyositis

Induced by various drugs or radiation treatment

  • Bleomycin
  • Amiodarone
  • Nitrofurantoin
  • Chemotherapy agents
    • Cyclophosphamide
    • Methotrexate

Idiopathic Interstitial Pneumonias

  • Idiopathic Pulmonary Fibrosis  (IPF)
  • Idiopathic Nonspecific Interstitial Pneumonitis (NSIP)
  • Acute interstitial pneumonia (AIP)/ Hamman-Rich syndrome
  • Desquamative interstitial pneumonia (DIP)
  • Respiratory bronchiolitis associated interstitial lung disease (RB-ILD)
  • Cryptogenic organizing pneumonia (COP)

Cigarette Smoke Exposure

Cigarette smoking, or often being exposed to cigarette smoke, places individuals at increased risk of developing idiopathic pulmonary fibrosis (IPF).  Smoking is also related to other idiopathic interstitial pneumonias (IIPs) including familial pulmonary fibrosis (FPF), respiratory bronchiolitis associated interstitial lung disease (RB-ILD), and desquamative interstitial pneumonia (DIP).


This information has been approved by David Schwartz, MD (February 2010).