What is sarcoidosis?

Sarcoidosis is pronounced: SAR-koy-DOH-sis

Sarcoidosis, also called sarcoid, is a condition where inflamed cells join together to make tiny lumps called granulomas. This can happen in any part of your body.

They are most often found in the lungs and the lymph nodes (glands). They can also affect your skin, eyes, joints, brain and heart, and other parts of the body.

When a lot of granulomas develop in one area, they cause swelling, which can affect how well that part of your body works. This causes different symptoms, depending on which part of the body is affected. If the granulomas continue to develop, the inflammation can cause lasting damage and scarring.

Sarcoidosis affects people in a lot of different ways. It can cause symptoms in just one part of your body or many parts at the same time. Sarcoidosis is not always a lung condition, but the lungs are affected in about 9 in 10 cases. This is called pulmonary sarcoidosis.

Pulmonary sarcoidosis is an interstitial lung disease (ILD). This means it affects your interstitium, the network of tissue that supports the air sacs (alveoli) in your lungs.

The cause of sarcoidosis is not known, but it’s related to your body’s defence system (immune system) not working properly.

Normally your immune system fights infections by releasing white blood cells into your blood to destroy bacteria and viruses. This causes the affected part of your body to become inflamed. We think sarcoidosis happens when the body’s defence (immune) system becomes too active and attacks the body’s own tissues and organs. We do not know why the immune system behaves this way.

You can get sarcoidosis at any age, but it’s most common in adults between 20 and 50 years old. It’s more common in Afro-Caribbean people. It’s more common in women than men.

You may also be more likely to get sarcoidosis if there is a history of the condition in your family.

It is also thought some environmental risk factors, such as bacteria or chemicals, can trigger sarcoidosis in people who are at higher risk of the condition.

Sarcoidosis is not contagious and cannot be passed from person to person.

Sarcoidosis is not a common condition: around 1 in every 10,000 people have sarcoidosis. It’s very rare for children to get sarcoidosis.