Vasculitis is a heterogeneous group of diseases in which inflammation and destruction of blood vessels are the main pathological changes, and its clinical manifestations vary depending on the type, size, location and pathological characteristics of the involved vessels. Vasculitis can be a solitary disease or one of the clinical manifestations of a particular disease, such as systemic lupus erythematosus, rheumatoid arthritis, dry syndrome, tumor, or infection; it can be systemic in itself, causing dysfunction of multiple systemic organs, or it can be confined to a single organ. Given the complexity and diversity of vasculitis, it can be referred to as a vasculitis syndrome. The etiology is unknown; the more definite causes include serum disorders, drug metaplasia, and infections; hepatitis B virus has been shown to be the cause of a variety of vasculitides. Clinically, there are two main categories: primary and secondary. The main clinical manifestations are: 1) multisystem damage; 2) active glomerulonephritis; 3) ischemic or stasis symptoms and signs, especially in young people; 4) elevated purpura and other nodular necrotizing rashes; 5) polyneuritis mononeuritis and unexplained fever.