Vasculitis is an inflammation of the blood vessels (vascular = blood vessels, itis = inflammation). Vasculitis can occur as a main disease or as a complication of another disease. Vasculitis may happen as the result of an infection, a medicine, or another disease or condition. Vasculitis can affect any blood vessel: arteries, veins and capillaries. Arteries deliver blood from the heart to organs. Veins return blood back to the heart. Capillaries are tiny blood vessels that connect small arteries and veins. When a blood vessel becomes inflamed the vessel can:
- Narrow, making it more difficult for blood to get through
- Close off completely so that blood cannot pass through
- Stretch and weaken the wall of the vessel causing collapse or bursting.