Causes of sarcoidosis
We don’t know what causes sarcoidosis, but we do know it’s related to your immune system behaving in a way it shouldn’t.
Normally your immune system fights infections by releasing white blood cells into your blood to destroy germs. This causes the affected part of your body to become inflamed, making it swollen or red.
Researchers think that sarcoidosis could be caused by something in the environment that stops your immune system working properly. Instead of attacking germs, it attacks healthy parts of your body.
Research also suggests that, for some people, the risk of getting sarcoidosis is related to their genes. Sometimes, more than one family member can get sarcoidosis. But there’s no evidence that it’s infectious.