Vasculitis is an inflamation of the blood vessels. Inflamation is a condition in which tissue is damaged by blood cells entering the tissues. These are mostly white blood cells which circulate and serve as our major defense against infection. Ordinarily, white blood cells destroy bacteria and viruses. However, they can also damage normal tissue if they invade it. Vasculitis can affect very small blood vessels (capillaries), medium sized blood vessels (arterioles or venules), or large blood vessels (ateries or veins).
Several things can happen to an inflamed vessel. If it is a small vessel, it may break and produce tiny areas of bleeding in the tissue. These areas will appear as small red or purple dots on the skin. If a larger vessel is inflamed, it may swell and roduce a nodule which may be felt if the blood vessel is close to the skin surface. The inside of the vessel tube may become narrowed so that blood flow is reduced, or the inside may become narrowed so that blood flow is reduced, or the inside may become totally closed (usually by a blood clot which forms at the site of inflamation). If blood flow is reduced or stopped, the tissues which recieve blood from that vessel begin to die. For example, a person wth vasculitis of a medium-sizd artery in the hand may develop a cold finger which hurts whenever it is used. Occasionally this can progress to gangrene.
WHAT CAUSES VASCULITIS
Vasculitis can be caused by:
1. Infection of the blood vessel walls
2. An immune or allergic reaction in the vessel walls.
The first cause is rare. When it occurs, viruses or fungi infect the blood vessel.White blood cells move in to destroy the infectious agents and damage the blood vessel in the process. This is a serious condition and requires prompt antibioic treatment.
The second cause of vasculitis, an immune reaction, is more common. Substances which cause allergic reactions are called "antigens." They cause the body to make proteins called "antibodies" which bind to the antigen for the purpose of getting rid of it. Antigen and antibody bound together are called "immune complexes." Two primary ways in which immune complexes destroy antigens are:
1. By attracting white blood cells to digest the antigen
2. By activating other body substances to help destroy the antigens.
Unfortunately, some immune complexes do not serve their purpose of destroying antigens. Instead, they remain too long in the body and circulate in the blood and deposit in tissues. They commonly accumulate in blood vessel walls, where they cause inflamation.
It is likely that some white blood cells which kill infectious agents (cytoxic cells) can also accidently damage blood vessels and cause vasculitis in some individuals.
DISEASES ASSOCIATED WITH VASCULITIS
Vasculitis can occur in may different illnesses. Some of the illnesses that can cause vasculitis are:
1. infections
2. Autoimmune Diseases -Lupus
-Rheumatoid Arthritis
-Polymyalgia Rheumatica
-Scleroderma
-Wegener's Granulomatosis
-Temporal Arteritis
-Cryoglobulinernia
3. Erytherna Nodosum
4. Tumors
-Leukemia
-Lymphoma
-Others
Vasculitis can also occur by itself without any obvious associated infection or other illness.
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