What is vasculitis?
Vasculitis refers to a rare group of conditions characterized by inflammation of blood vessels. It occurs when the immune system attacks a person's own blood vessels. The cause of vasculitis is often unknown. In the absence of an identifiable cause, it is called primary vasculitis. When an underlying cause can be identified, it is called secondary vasculitis. Secondary vasculitis may be triggered by an allergic reaction to a medication, in response to an infection such as hepatitis C, or as a result of an autoimmune disease, such as rheumatoid arthritis. In some cases, secondary vasculitis is seen as a complication of blood cell cancers such as leukemia and lymphoma.
Vasculitis can affect any type of blood vessel, including veins, arteries, and capillaries. It can result in narrowed or blocked vessels that limit the circulation of blood, leading to tissue or organ damage. In some cases, a bulge in a weakened vessel, called an aneurysm, can occur. An aneurysm can be a life-threatening complication because it can rupture, leading to heavy internal bleeding.
There are many types of vasculitis, which are often classified according to the size of the affected blood vessels. On the next page is a table containing examples of types of vasculitis.