Silicosis is an incurable lung disease caused by inhaling large amounts of silica dust, usually over a period of many years.
Silica (silicon dioxide) is a substance naturally found in certain types of stone, rock, sand and clay. Working with these materials can create a very fine dust, known as respirable crystalline silica, which can be easily inhaled.
Once inside the lungs, the dust particles are attacked by the immune system. This causes inflammation (swelling) and gradually leads to areas of hardened and scarred lung tissue (fibrosis). Eventually, the lungs may stop working properly.
People who work in the following industries are particularly at risk:
- construction and demolition – because of exposure to bricks, concrete and mortar
- pottery, ceramics and glass manufacturing
- mining and quarrying
- sand blasting and stone cutting
What are the symptoms?
Early symptoms of silicosis are a cough and shortness of breath. Then, as the disease gets worse, it can cause weight loss, extreme tiredness, wheezing and sometimes swollen fingers (finger clubbing).
However, it usually takes many years of exposure to silica dust before these symptoms start. Most people who develop silicosis will have been exposed to low amounts of silica dust for more than 20 years, without being aware anything was wrong. Doctors may refer to these typical cases as ‘simple chronic silicosis’.
Silicosis can also happen after exposure to larger amounts of silica over a shorter period of time (about 5–15 years), but this is more unusual.
Acute silicosis – caused by short-term exposure to very large amounts of silica – is rare. In these cases, the cough and shortness of breath can appear within days or weeks of exposure to silica, with weight loss, tiredness and wheezing developing within a few months or years.
In rare cases, the lungs may become severely scarred – a condition called progressive massive fibrosis. This causes shortness of breath, which gets progressively worse, and increases the risk of other complications developing (see below).
How can my doctor help?
Your doctor may suspect silicosis after asking about your symptoms and work history and listening to your lungs with a stethoscope. They will want to know about any periods when you may have been exposed to silica and whether you were issued with any safety equipment, such as a face mask, when you were working.
If silicosis is suspected, you may be referred to a specialist for further tests to confirm the diagnosis. These tests can include:
- a chest X-ray to detect abnormalities in the structure of your lungs
- a computerised tomography (CT) scan of your chest, to produce more detailed images of your lungs
- lung function testing (spirometry), which involves breathing into a machine called a spirometer to assess how well your lungs are working
You may also be asked to take a skin test for tuberculosis (TB), known as a Mantoux test. The test involves injecting a substance called PPD tuberculin into your forearm.
If you have a latent TB infection (TB bacteria are alive but inactive in your body), your skin will be sensitive to PPD tuberculin and a hard red bump will develop at the site of the injection, usually within 48 to 72 hours of having the test.
How is silicosis treated?
There is no cure for silicosis, as the lung damage cannot be repaired. Treatment aims to relieve symptoms and improve quality of life. The condition will often continue to get worse, leading to further lung damage and serious disability.
It is important to take the following steps, which help limit the risk of complications developing:
- ensure you are not exposed to any more silica
- stop smoking (if you smoke)
- have regular skin tests to check for tuberculosis (TB), as silicosis makes you more prone to TB and other infections
The influenza vaccination and pneumococcal vaccination are also recommended. Your doctor can arrange for you to have these. Antibiotics may be prescribed to treat any chest infections that develop.
You may be offered long-term oxygen therapy if you are having difficulty breathing and have low levels of oxygen in your blood.
Bronchodilator medicines can also be prescribed, which relax the muscles in your lungs and airways.
In very severe cases of silicosis, a lung transplant may be an option, although there are strict health requirements to meet before this will be considered.
What are the possible complications?
Silicosis can increase your risk of other serious conditions developing, including:
The above links will take you to more information on these conditions, including their treatment.
How many people are affected?
It is difficult to determine the number of people affected by silicosis, as it can take many years for symptoms to appear.
Most cases of silicosis nowadays are the result of exposure to silica that happened before workplace regulations were introduced (see below).
How can silicosis be prevented?
Your employer should warn you about any risks to your health, and supply you with the necessary equipment to protect you from exposure to silica dust.