Interstitial lung disease (ILD) includes a large group of disorders that affect the interstitium part of the lung. The interstitium lies between the alveolar sacs in the lung where gas exchange occurs. The small air tubes (called bronchioles) may also be affected.

In interstitial lung disease, the interstitium can be abnormal due to:

  • Scar tissue (called pulmonary fibrosis)
  • Buildup of too many or different cells
  • Injuries or changes to the lung structure

Interstitial lung disease is uncommon in children.