IPF is one of the most common forms of interstitial lung disease (ILD). Many types of ILD have a known cause, but sometimes the cause is unknown. When the cause of ILD is unknown, it’s called idiopathic interstitial pneumonia. IPF is one type of idiopathic interstitial pneumonia.

Unlike other types of ILD with scarring that may or may not get worse over time, IPF causes progressive lung scarring, which means scarring of the lungs that gets worse over time. Sometimes this is called worsening fibrosis. Because IPF may progress at varying rates, it’s important to take action early.