Vasculitis means inflammation of blood vessels. The inflammation can be short term (acute) or long term (chronic), and it can be so severe that it reduces blood flow to tissues and organs. This can cause significant organ and tissue damage, especially when vasculitis affects blood vessels in the brain, lungs, kidneys or other vital areas.
Although the cause of most forms of vasculitis remains unknown, many forms probably are related to a problem with the immune system. One theory is that, for unknown causes, the immune system attacks the blood vessels, which causes them to become inflamed. Some researchers think this immune attack might be triggered by an infection, drug or something else in the environment.
There are many different forms of vasculitis, including:
Polyarteritis nodosa – This affects small- to medium-sized blood vessels in many different parts of the body, especially the skin, intestines, kidneys and nerves. It is a progressive illness, meaning it continues to get worse, and it can lead to death. It typically occurs in adults in their late 40s or early 50s, and it affects men two to three times more often than women.
Hypersensitivity vasculitis – This affects the smallest blood vessels (including arterioles, veins and capillaries), especially those in the skin. Hypersensitivity vasculitis can be triggered by an allergy (especially a reaction to a medication) or an infection but often the cause is unknown.
Giant cell arteritis (also called temporal arteritis) – This affects medium to large arteries, including those around the scalp, face, eye and the aorta as it travels from the heart and separates into branches leading to the neck and head. It usually affects people over the age of 55. It is rare among African-Americans, but it is relatively common among whites of Scandinavian ancestry. Studies suggest that at least part of the tendency to develop this illness is genetic (inherited).
Wegener's Ggranulomatosis with polyangiitis (Wegener's)– This affects small- and medium-sized blood vessels in the kidneys and in the upper and lower respiratory tract (for example, sinuses and lungs). It can occur in any age group and affects both sexes equally. The average age at the time the disease starts is 40, with only 15 percent of cases occurring in children and adolescents. It is rare among African-Americans.
Takayasu's arteritis (also called aortic arch syndrome or pulseless disease) – This vasculitis affects medium- and large-sized arteries, especially the aortic arch and its branches near the heart. It most commonly affects teenage girls and young women, and it is most common in Asia.
Kawasaki disease – This vasculitis affects the lymph nodes, skin, mucous membranes, and heart, including the coronary arteries (arteries that supply blood to the heart). It is seen most commonly in children.