Idiopathic pulmonary fibrosis (IPF) is the most common type of pulmonary fibrosis. It is a disease that causes scarring (fibrosis) of the lungs. The word "idiopathic" means it has no known cause. Scarring causes stiffness in the lungs and makes it difficult to breathe.
Lung damage from IPF is irreversible and progressive, meaning it gets worse over time. In some cases, it can be slowed by certain medications. Occasionally, people with IPF will be recommended for lung transplant.