This website is for informational use only and does not provide any medical advice.

What is interstitial lung disease?

Interstitial lung disease (ILD) is a group of disorders in which the lungs develop significant and sometimes disabling inflammation, scar tissue or fibrosis within the tissues. This may be due to pulmonary fibrosis or other similar problems. Idiopathic pulmonary fibrosis (IPF) is the most common ILD. Other names for ILD are:

  • Diffuse parenchymal lung disease
  • Alveolitis
  • Idiopathic pulmonary pneumonitis (IPP)

ILD limits the transfer of oxygen across the membranes of the lung, making breathing difficult. Around the air sacs in the lungs is tissue called the interstitium. When the tissue is stiff or scarred, the body experiences a lack of oxygen because the air sacs aren’t able to fully expand.


  • Shortness of breath, the main symptom of ILD, causing you to breathe faster, harder, or more shallowly, or to take more deep breaths
    • Initially, this symptom may not be severe and occurs with exercise, stair climbing, and other physically demanding activities.
    • Over time, it may become more obvious during less strenuous activity, such as ordinary daily tasks, and then even when you are eating or talking. To take deep breaths, you may need to lean forward.
  • A dry cough, a symptom most people with ILD have
  • Gradually, weight loss, fatigue and muscle and joint pain occur.
  • “Clubbing” as the disease progresses: a condition in which there may be abnormal enlargement of the base of the fingernails
  • Cyanosis, in which your lips, skin or fingernails turn blue because of inadequate blood oxygen
  • Frequent headaches
  • Sleepiness or confusion
  • Fever
  • Coughing up dark mucus


  • Autoimmune diseases such as lupus, rheumatoid arthritis, sarcoidosis and scleroderma
  • Lung inflammation due to breathing in a foreign substance, including particular types of dust, fungus or mold (hypersensitivity pneumonitis)
  • Medications such as nitrofurantoin, sulfonamides, bleomycin, amiodarone, methotrexate, gold salts, infliximab and etanercept
  • Radiation treatment of the chest
  • Occupational lung disease (working with or around asbestos, coal dust, cotton dust and silica dust, in jobs such as coal mining, sand blasting or working on a ship)
  • Cigarette smoking, which may increase the risk of developing some form of ILD and may cause the disease to be more severe.


A routine physical exam with a stethoscope can detect dry, crackling sounds in the chest. People who are heavily exposed to known causes of lung disease in the workplace are usually routinely screened for lung disease. According to the NLM/NIH, other diagnostic tests that may be performed are:

  • Blood tests to check for connective tissue diseases
  • Bronchoscopy, with or without biopsy
  • Chest X-ray
  • Computed tomography (CT) scan of the chest
  • Echocardiogram
  • Open lung biopsy
  • Measurement of the blood oxygen level at rest or when active
  • Pulmonary function tests
  • Six-minute walk test (to see how far you can walk in six minutes and how many times you need to stop to catch your breath)

Living with

If there is no applicable medical or surgical treatment for your particular type of ILD, there are measures you can take toward lung rehabilitation:

  • Quit smoking
  • Learn different breathing methods
  • Arrange your home to help you save your energy when moving around
  • Eat the proper amount of calories and nutrients
  • Stay active and increase your strength