Vasculitis Causes and Risk Factors

Vasculitis is an unexpected response by your body’s immune system that causes it to attack your blood vessels. What causes vasculitis is not fully known, but when it does occur, your blood vessels may narrow or close off as the vessel walls get thicker. Rarely, the blood vessel wall may weaken, causing it to expand or bulge. This bulge is known as an aneurysm.

**Effects of inflammation on an artery.** This series of images shows a normal artery (Figure A), a narrowed artery with inflammation (Figure B), a totally blocked (occluded) artery (Figure C), and an artery with abnormal blood flow through an aneurysm (Figure D). Inflammation is your body’s natural reaction to infection or injury.

What are the risk factors for vasculitis?

Age

Vasculitis can develop at any age. However, some types of vasculitis are more common among people at particular ages.

Buerger’s disease usually affects men younger than age 45 who smoke or have smoked.
IgA vasculitis is diagnosed more often in children than adults.
Giant cell arteritis affects adults age 50 and older and is most common in people who are in their 70s and 80s.
Kawasaki disease is most common in children under age 5.
Takayasu arteritis is most common in women between ages 20 and 40.

Family history

Certain types of vasculitis, including the following, may run in families:

Behçet’s disease
Granulomatosis with polyangiitis
Kawasaki disease

Lifestyle habits

Lifestyle habits that can raise your risk of developing vasculitis include:

Smoking.
Using illegal drugs, such as cocaine.

Medicines

Many medicines, including those listed below, have been linked to a higher risk of vasculitis.

Hydralazine is used to treat high blood pressure.
Levamisole is used for infections, but is also commonly added to cocaine.
Propylthiouracil is used to treat some thyroid disorders.
Allopurinol is used for gout.
Tumor necrosis factor inhibitors are used to treat some autoimmune diseases.

Other medical conditions may trigger vasculitis, too.

Autoimmune disorders, such as lupus, rheumatoid arthritis, and scleroderma can lead to vasculitis.
COVID-19 can raise the risk of many types of vasculitis or trigger flares (repeat occurrences or worsening of symptoms) in children and adults who have a history of vasculitis.
- Multisystem inflammatory syndrome (MIS-C) in children, which occurs after a COVID-19 infection, may also lead to vasculitis.
Hepatitis B or C infections sometimes trigger vasculitis.
Lymphoma, a cancer of the blood, is another possible vasculitis trigger.

Race or ethnicity

Behçet’s disease is most common in people of Turkish descent and is relatively common in other countries in the Mediterranean, the Middle East, Central Asia, China, and Japan. It is relatively uncommon in Northern and Western Europe and the United States.
Giant cell arteritis is more common in people of Northern European ancestry.
Kawasaki disease is more common among children of Japanese descent.

Sex

Behçet’s disease is more common in men in some countries and more common in women in other countries.
Buerger’s disease is more common in men.
Giant cell arteritis affects women 2 to 4 times more often than men.
Microscopic polyangiitis affects men slightly more often than women.

Can vasculitis be prevented?

Some types of vasculitis cannot be prevented because they are caused by autoimmune disorders. However, depending on what caused the vasculitis, it is possible to prevent some types from flaring up.

Your healthcare provider may prescribe medicines to reduce symptoms.

Anticoagulant medicines prevent blood clot from forming. You may need them if you have an aneurysm.
Beta blockers lower blood pressure. You may need them if you have an aneurysm.
Statins control or lower high blood cholesterol levels and have anti-inflammatory effects.

Your provider may also recommend healthy lifestyle changes.

Adopt a heart-healthy lifestyle.
Avoid illegal drugs, including cocaine. If you use illegal or street drugs, ask your healthcare provider how to get help to stop. You can also call the Substance Abuse and Mental Health Services Administration’s (SAMHSA) National Helpline at 1-800-662-HELP.
Quit smoking and tobacco. Visit Smoking and Your Heart and the National Heart, Lung, and Blood Institute’s Your Guide to a Healthy Heart. Although these resources focus on heart health, they include basic information about how to quit smoking. For free help and support to quit smoking, you may call the National Cancer Institute’s Smoking Quitline at 1-877-44U-QUIT (1-877-448-7848).