Interstitial lung disease (ILD)
What is ILD?
Interstitial lung diseases are a group of conditions affecting the tissue around the lung air sacs. They can cause inflammation, scarring (pulmonary fibrosis), or both. The exact type matters because treatments and outlook differ.
Examples include idiopathic pulmonary fibrosis, hypersensitivity pneumonitis (previously called extrinsic allergic alveolitis), occupational lung disease such as asbestosis or silicosis, and lung involvement from autoimmune or connective tissue disease. Some medicines can also cause ILD.
Symptoms
Common symptoms include gradually increasing breathlessness, a persistent dry cough and fatigue. These symptoms have many possible causes and do not establish the diagnosis on their own.
How is it diagnosed?
Assessment includes your medicines, previous illnesses, work and home exposures, and any family history. Tests commonly include a high-resolution CT scan, full lung function including gas transfer, oxygen measurements and selected blood tests. Specialists review the findings together in an ILD multidisciplinary team. Bronchoscopy or a biopsy is sometimes considered when it would help clarify the diagnosis; it is not required for everyone.
How is it treated?
Treatment is matched to the ILD subtype. It may involve removing a relevant exposure, specialist anti-inflammatory treatment or an antifibrotic medicine for eligible fibrotic disease. Antifibrotics may slow further scarring but do not reverse existing fibrosis. Do not stop prescribed medicines without discussing this with your clinician.
Rehabilitation, appropriate vaccinations, stopping smoking, oxygen assessment when needed and symptom support are also important. Regular review tracks symptoms and lung function; selected patients may be assessed for transplantation.
When to seek urgent help
New or rapidly worsening breathlessness needs prompt medical assessment. Call 999 for severe breathing difficulty, blue or grey lips or sudden confusion.
Sources and further information
Asthma + Lung UK: ILD and pulmonary fibrosis
Asthma + Lung UK: ILD diagnosis
Asthma + Lung UK: ILD treatments
NICE CG163: specialist assessment of suspected IPF
General information for adults; investigation and treatment are tailored to you.