What is interstitial lung disease?

Interstitial lung disease (ILD) is a group of over one hundred lung conditions that cause stiffening, inflammation and progressive scarring to the lung tissue (fibrosis).

The thickening and scarring of the lung tissue makes it harder for the lungs to transfer oxygen into the bloodstream, in turn reducing oxygen supply to vital organs.

Royal Brompton Hospital’s interstitial lung disease unit has expertise in the specialist management of a wide range of these interstitial and rare lung diseases, including:

  • sarcoidosis
  • idiopathic pulmonary fibrosis (IPF)
  • non-specific interstitial pneumonitis (NSIP)
  • hypersensitivity pneumonitis
  • pleuroparenchymal fibroelastosis (PPFE)
  • connective tissue disease-associated lung disease
  • vasculitis associated lung disease
  • lymphangioleiomyomatosis (LAM)
  • Langerhan’s cell histiocytosis
  • alveolar proteinosis
  • drug-induced lung disease
  • cryptogenic organising pneumonia (COP)
  • alveolar microlithiasis

Interstitial lung disease symptoms

The main symptoms of ILDs are:

  • a dry cough
  • difficulty breathing (especially upon exertion)

Other symptoms include:

  • weight loss
  • prolonged tiredness
  • clubbed fingertips or nails

What causes interstitial lung disease?

In the majority of cases the cause is unknown, although triggers may include:

  • workplace pollutants such as silica, asbestos, grain dust and animal and bird droppings
  • medical conditions such as sacoidosis and some autoimmune diseases like rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis
  • certain medications can cause ILD such as those used to treat irregular heartbeats, chemotherapy drugs and some antibiotics


Diagnosing interstitial lung disease

Determining the cause of interstitial lung disease (ILD) can be extremely difficult, particularly due to the number of conditions that constitute an ILD and the fact that symptoms mimic those relating to other conditions.

Some of the following tests may be required:

Diagnostic scans

A chest x-ray, CT scan, or echocardiogram (ECG) can identify the pattern of scarring to the lungs.

Lung function tests

Diagnostic tests for lung conditions like ILD include measure breathing capacity with spirometry, oximetry or exercise stress tests.

Analysis of lung tissue

The lung tissue is analysed through one or more of the following methods:

  • bronchoscopy (insertion of thin tube via nose or throat)
  • bronchoalveolar lavage (injection of salt water into lung)
  • surgical biopsy (retrieval of larger amounts of lung tissue via surgery)

Interstitial lung disease treatment

Treatment for interstitial lung disease will depend on the type of the lung condition and its cause. Treatment may include:


Antibiotics are used to eliminate bacteria, or corticosteroids or immunosuppressant drugs are used to suppress the immune system.

Oxygen therapy

This treatment may be recommended for those with low oxygen levels in their body to improve breathing, and protect the heart.

Lung transplantation

Only as a last resort, lung transplantation may be offered to patients with ILD who have not responded to other treatment.

Discover our respiratory medicine experts

Meet our team of leading lung and respiratory medicine specialists. From pulmonary health to advanced interventions, our experts are dedicated to providing personalised care tailored to your respiratory needs.