Systemic Vasculitis: Causes

Vasculitis is an inflammation of the blood vessels, but what causes the inflammation is often unknown. It is sometimes a side effect of the body's immune system response to a recent or chronic infection. It also can be a side effect of the body's response to a medicine. The body sometimes recognizes a medicine as a foreign substance, and may develop an "allergic reaction" to try to get rid of it.

This information has been adapted from the National Heart Lung and Blood Institute.