Vasculitis

**Semantic type:** Disease or Syndrome

**Definition:** An inflammatory process involving the wall of the vessels (large, medium, or small-sized vessels). The inflammatory process may cause necrosis or formation of granulomas in the vascular wall. It may be the result of an autoimmune disorder, infection, or malignancy. Representative examples include polyarteritis nodosa, temporal arteritis, Wegener granulomatosis, Kawasaki disease, Takayasu arteritis, and Henoch-Schonlein purpura.