Pleural thickening and pleural plaques – What are the differences?

Posted: 13th Aug 18 10:30 AM

Pleural plaques are areas of localised scarring or calcification found on the pleura (the lining of the lungs and rib-cage).

Pleural thickening refers to larger areas of scarring and calcification of the pleura and can often become widespread, known as diffuse pleural thickening (DPT), which can cause breathing and respiratory problems.

Both of these diseases can be caused by exposure to asbestos dust and fibres, but affect your body in different ways.

What is the pleura?

Before looking into the differences of these diseases and what effects they have on your health, you should know more about what part of the body they affect.

The pleura is a thin membrane found inside the rib-cage and surrounds each lung. It is a protective tissue and consists of two layers – the inner layer and the outer layer.

The inner layer of the pleura, known as the visceral pleura, covers the lungs.

The outer layer, known as the parietal pleura, lines the rib-cage and the diaphragm.

Together, the two layers of the pleura allow for smooth and unrestricted movement of your lungs within the chest cavity.

Does pleural plaques cause any symptoms?

In almost all cases of pleural plaques there are no symptoms and they cause no problems to long term health. Pleural plaques simply indicate that there has been exposure to asbestos.

Symptoms of pleural thickening

In the majority of cases, pleural thickening has little or no impact on a person’s health or life span. The disease usually progresses slowly and in many cases remains stable.

Diffuse pleural thickening (DPT) is diagnosed when the pleura thickens to the extent that it causes breathlessness. This condition is frequently, but not exclusively, caused by exposure to asbestos dust and fibres.

When pleural thickening is found across both lungs, it is referred to as bilateral pleural thickening.

DPT can be either bilateral or unilateral, affecting only one lung.

When the lungs become calcified or scarred as a result of DPT, the elasticity of the pleural membrane is reduced, which can result in impairment of lung function.

Symptoms of pleural thickening vary from person to person and, depending on the progression of the disease, it can be a debilitating condition which can substantially deteriorate the quality of life of the sufferer.

The main symptoms of pleural thickening present themselves as moderate to severe breathlessness and chest pains, which usually manifest after exertion.

Extensive pleural thickening can also result in a blunting or obliteration of the costophrenic angles – the area where the ribs meet the diaphragm.

What causes pleural plaques?

Pleural plaques form when inhaled asbestos fibres become lodged in the lungs. From the regular movement made while you breathe, they can work their way through to the pleura, which in turn can become torn and damaged.

As this damage made by the asbestos heals, it can scar and become calcified, forming pleural plaques.

Pleural plaques are usually “focal” in nature – they only form in small, singular areas, unlike pleural thickening which is more widespread.

It only takes minimal exposure to asbestos dust and fibres to cause pleural plaques to develop. For this reason, many people who worked in the following industries are at a higher risk of developing the disease:

  • Carpenters and joiners
  • Heating and ventilation engineers
  • Pipe fitters
  • Painters and decorators
  • Shipwrights
  • Electricians and electrical fitters
  • Energy plant operatives
  • Railway engineers

This is not an exhaustive list.

Although pleural plaques are symptomless, it is important to remember if you have been diagnosed with them, as they are indicative of you being exposed to asbestos. Because of this, you may also be at a higher risk of developing another, more serious asbestos-related disease.

If you have been diagnosed with pleural plaques, it is useful to make a list of your past employment, noting where and how you could have been exposed to asbestos.

What causes pleural thickening?

Similar to pleural plaques, pleural thickening can develop after the inhalation of asbestos dust and fibres.

Also like pleural plaques, pleural thickening forms when the asbestos fibres work their way through the lung tissue to the pleura. The “thickening” develops from extensive scarring and calcification – enough to restrict the movement of the pleura and the lungs and cause respiratory impairment.

People who worked in industries where asbestos was regularly used, such as those mentioned previously, are at a higher risk if developing pleural thickening.

It is also possible to develop pleural thickening if you lived with someone who worked with and was exposed to asbestos. This could have happened when asbestos fibres were carried home on clothing or tools and inhaled by others in the family. Some people who develop pleural thickening cannot remember coming into contact with asbestos and might not have been aware they were exposed to it at the time.

Pleural thickening develops over a period of many years after initial exposure to asbestos. This latency period is usually between 10 and 50 years.

While exposure to asbestos is often the cause of pleural thickening, there are also other known causes, such as:

  • Pneumonia
  • Tuberculosis
  • Rheumatoid lung disease
  • Injury to the ribs, e.g. blunt trauma and breaks
  • Tumours (benign or malignant)
  • Chemotherapy
  • Radiotherapy

If you are diagnosed with pleural thickening, or your doctor suspects you may have it, make sure to tell them about any previous exposure to asbestos throughout your working life.

If you or a loved one is ever diagnosed with pleural thickening, pleural plaques, or another asbestos-related condition, don’t hesitate to get in touch with the National Asbestos Helpline. We’re here to help you with advice about your condition and how to cope with it, and can also advise on any benefits and/ or compensation you might be entitled to. Call us on Freephone 0800 043 6635, or email

Further reading

What is the difference between mesothelioma and asbestosis?

Emotional needs of people exposed to asbestos revealed by study

Why is asbestos still causing thousands of deaths every year?

Peace of mind with our expert asbestos solicitors