Interstitial Lung Disease (ILD)

Interstitial Lung Disease

What is Interstitial Lung Disease (ILD)?

Interstitial lung disease or ILD is the umbrella term in Singapore for more than 200 lung diseases that cause inflammation and scarring or fibrosis of the lungs1. The lungs are made up of the bronchi, bronchioles, and the alveoli. When air is inhaled it travels down the windpipe or trachea into the bronchi, then the bronchioles, and eventually the alveoli. The alveoli are where the exchange of gases takes place with the blood – where oxygen is supplied, and carbon dioxide is removed.

Interstitial lung disease, which is also known as diffuse parenchymal lung disease (DPLD), occurs when inflammation and scarring damages the interstitial tissues between the alveoli and the blood vessels2. When this happens, it makes it difficult for the exchange of gases to take place, resulting in lung infections or respiratory failure. 

Illustration of Interstitial Lung Disease

There are many types of interstitial lung disease, some examples include3,4:

  • Idiopathic pulmonary fibrosis: most common type of ILD but its cause is unknown.
  • Interstitial pneumonia: can be caused by fungal, bacterial, or viral infections but the most common cause is the bacteria Mycoplasma pneumoniae.
  • Asbestosis: inflammation and scarring of the lungs caused by inhaling asbestos fibres.
  • Bronchiolitis obliterans: causes blockages in the bronchioles.
  • Sarcoidosis: type of disease that causes clumps of inflammatory cells form in multiple organs such as the lungs and lymph nodes.
  • Hypersensitivity pneumonitis: inflammation of the alveoli due to long-term inhaling of allergic substances such as dust or mold.
  • Nonspecific interstitial pneumonitis: affects people with autoimmune disorders such as scleroderma and rheumatoid arthritis.

What are the causes of Interstitial Lung Disease?

The main cause of most interstitial lung disease is unknown. However, the general consensus is that injury or inflammation to your lungs, results in interstitial lung disease in some individuals. When an injury occurs, your lungs should be able to generate the right amount of healing, but in people with ILD, this healing gets exaggerated resulting in scarring or fibrosis. 

Some causes of interstitial lung disease include3:

  • Occupational hazards: asbestos, grain dust, bird proteins, coal dust, talc, salica dust.
  • Infectious substances: viral, bacterial, fungal.
  • Medications: some anti-inflammatory drugs, some antibiotics, heart medications, and chemotherapy drugs.
  • Autoimmune diseases: such as lupus, scleroderma, rheumatoid arthritis

What are the common symptoms of Interstitial Lung Disease (ILD) in Singapore?

When the interstitial tissue between the alveoli and blood vessels is damaged, not enough oxygen is getting to other parts of the body and not enough carbon dioxide is leaving the body. This can result in the following symptoms4:

  • Breathlessness: also known as dyspnoea or shortness of breath. 
  • Dry cough: non-productive cough.
  • Fatigue or lethargy: when you are not getting enough oxygen, you will feel fatigue.
  • Chest pain: more pronounced when breathing.
  • Unintentional weight loss: due to a loss of appetite.

Is Interstitial Lung Disease painful?

Yes, interstitial lung disease can cause chest pains that are more pronounced when breathing.

Who is at risk of interstitial lung disease in Singapore?

Anyone can get interstitial lung disease, however, individuals with the following factors have a higher risk:

  • Gender: men are more likely than women to get ILD
  • Age: the older you get the higher the risk
  • Smokers: individuals who smoke have a higher risk of some ILD
  • Gastroesophageal reflux disease (GERD): if you have uncontrolled acid reflux you have a higher risk.
  • Genetics: some ILD are passed down from family members.

How is Interstitial Lung Disease diagnosed?

If an interstitial lung disease is suspected, the following diagnostic tests will be conducted3:

  • Chest x-ray: imaging of your lungs may show fine lines if you have ILD.
  • Computed tomography scan (CT-scan): like an x-ray but clearer and more accurate, usually able to identify an ILD.
  • Lung function test: spirometry or peak flow readings can identify how your lungs are functioning. 
  • Lung biopsy: tissue is biopsied to look for signs of ILD.
  • Bronchoscopy: a long, thin tube with a light and camera attached at one end is inserted into your lungs to search for the presence of ILD.
  • Blood tests: to check for the cause of ILD.

What are the treatment options for Interstitial Lung Disease (ILD) in Singapore?

There is no cure for interstitial lung disease, treatment is used for the underlying cause and to alleviate your symptoms.

Treatment options include:

  • Medications: such as corticosteroids, biologic drugs, antibiotics, anti-fibrotic and cytotoxic drugs
  • Surgery: lung transplant
  • Pulmonary rehabilitation: helps improve your activity level 
  • Oxygen supplementation: used if you have low oxygen levels

Frequently asked questions

Is interstitial lung disease hereditary?

Some interstitial lung disease can be passed down from family members.

How long can you live with interstitial lung disease?

The survival varies by the type of Interstitial lung disease. Among different types of interstitial lung diseases, idiopathic pulmonary fibrosis has poorest survival which can range from 3-5 years or longer. 

Is interstitial lung disease contagious?



  1. H D Jiang, B. C. (2021). [Interstitial lung disease revisited]. Zhonghua Yi Xue Za Zhi, 1453-1457.
  2. Cleveland Clinic Medical Professional. (2022, August 5). Interstitial Lung Disease. Retrieved from Cleveland Clinic: 
  3. Hoffman, M. (2021, November 3). Interstitial Lung Disease (ILD). Retrieved from WebMD:
  4. Watson, S. (2022, March 11). Interstitial Lung Disease. Retrieved from healthline: 
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