Vasculitis - Causes - Causes

Vasculitis occurs when your immune system injures your blood vessels by mistake. What causes this to happen is not fully known, but when it occurs, your blood vessels become inflamed and can narrow or close off. 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
Effects of inflammation on an artery. Figure A shows a normal artery with normal blood flow. The inset image shows a cross-section of the normal artery. Figure B shows an inflamed, narrowed artery with decreased blood flow. The inset image shows a cross-section of the inflamed, narrowed artery. Figure C shows an inflamed, blocked artery and scarring on the artery wall. The inset image shows a cross-section of the inflamed, blocked artery. Figure D shows an artery with an aneurysm caused by inflammation. The inset image shows a cross-section of the blocked artery. 

Do you want to know more about what causes vasculitis?