In this section, we explain what diffuse (or widespread) pleural thickening is, symptoms, how it’s diagnosed and how it’s treated.
Inside your chest there are two thin layers of cells - called the pleura or pleural membrane. Each layer is about as thin as the skin of a balloon. The inner layer covers your lungs and the outer layer lines the inside of your rib cage.

Diffuse (or widespread) pleural thickening is where extensive, often smooth scarring, thickens large parts of the pleural membrane lining your lungs and chest wall. Asbestos exposure is not the only cause of diffuse pleural thickening. Other causes include infection, inflammatory conditions and non-malignant (not cancerous) pleural effusion, which is when there is fluid around the lungs. In all of these cases, one or both lungs could be affected.
Symptoms of diffuse pleural thickening
When your pleura becomes thicker and hard over a large area, your lungs cannot expand as far as they used to and you may feel breathless.
Diagnosing diffuse pleural thickening
Your GP may refer you to a specialist for consideration of further tests such as lung function tests and a CT scan. A CT scan is a special X-ray machine that takes a picture of a cross-section of your body. Occasionally it will be necessary to take a sample, or biopsy, from the thickened pleural membrane to exclude a diagnosis of mesothelioma.
Treating diffuse pleural thickening
In most cases, no treatment is needed since the pleural thickening does not usually cause very severe symptoms. Stopping smoking, keeping active and pulmonary rehabilitation (PR) are usually the most helpful options. If your breathlessness is severe, surgery can very occasionally be considered. This is rare, as it is not usually very effective and is a major operation.