The cause is unknown, hence the term idiopathic. Risk factors include cigarette smoking, acid reflux disease (GERD), certain viral infections, and genetic predisposition. The underlying mechanism involves scarring of the lungs. Diagnosis requires ruling out other potential causes. It may be supported by a HRCT scan or lung biopsy which show usual interstitial pneumonia (UIP). It is a type of interstitial lung disease (ILD).
