Vasculitis

of the blood vessel walls. This inflammatory process can occur without a known cause (primary vasculitis), for autoimmune reactions, as a result of an infectious process or in association with another pathological condition (secondary vasculitis).

Any blood vessel can be affected by vasculitis, which - depending on the location of the inflammatory process - can develop a wide spectrum of diseases, which can vary considerably in symptoms, severity and duration.

: this becomes "hyperactive" and mistakenly recognizes the blood vessel cells as foreign and dangerous, then attacks them as if they were a bacterium or a virus. It is not always clear why this happens, but an infection, certain cancers and immune system disorders, certain medications, or an allergic reaction often act as a trigger.
The inflammatory process causes changes in the walls of the blood vessels. Vasculitis narrows the lumen of vessels, reducing the amount of blood that reaches tissues and organs. In some cases, blood clots or granulomas may form in an affected vessel, obstructing blood flow. Other times, instead of reducing its size, vasculitis weakens the blood vessel, leading to the onset of an aneurysm.