Interstitial lung disease describes a group of disorders caused by damage to the lungs, which are the organs through which we breathe. This damage can cause difficulty breathing and low oxygen levels in the blood. Although the exact cause of interstitial lung disease is unknown, it can be triggered by various injuries resulting in scarring within the lungs. Normally, the body fixes the damaged lung tissue, but in patients with interstitial lung disease the repair process does not function properly, causing thick and scarred air sacs. Other risk factors include long-term exposure to hazardous materials, certain autoimmune diseases, such as rheumatoid arthritis, age, and smoking. Once the lung tissue starts scarring, medication can only slow down the damage but it cannot reverse the damage. Treatment may include radiation, chemotherapy drugs, heart medications or antibiotics.