The clinical manifestations of vasculitis vary depending on the type, size, and location of the involved vessels, the stage of inflammation, and the characteristics of the lesion. Dysfunction occurs due to narrowing of the vascular lumen and impairment of blood supply to organs as a result of inflammation. The classification can be elaborated according to the size of the vessels affected by vasculitis. Vasculitis can involve large vessels, medium vessels, and small vessels. The most predominant vasculitis of large vessels is giant cell arteritis and large arteritis, medium-sized vasculitis is most commonly associated with polyarteritis nodosa and Kawasaki disease, and small vasculitis is most typically associated with granulomatous Weyers and allergic granulomatous vasculitis. The representative type of lesion for large vasculitis is aortitis. If the head and arm trunk, vertebral artery, or carotid artery are involved, dizziness, memory loss or even syncope and stroke may occur; if the subclavian artery is involved, pulselessness, decreased blood pressure, and chilled skin of the upper limbs may occur; if the renal artery is involved, hypertension, proteinuria, hematuria, or even decreased renal function and kidney atrophy may occur; if the lung is involved, pulmonary hypertension and lung infection may be combined. Moderate sized vasculitis is represented by nodular polyarteritis. Polyarteritis nodosa is most commonly associated with renal, cardiac, neurological, and cutaneous involvement. Involvement of the kidneys often presents with hypertension and azotemia. The skin presents with subcutaneous nodules, rash, and purpura. Neurological manifestations include peripheral nervous system and central nervous system injuries, with peripheral nervous system manifesting as neuritis and central nervous manifesting as impaired consciousness and cerebrovascular accidents. Small-vessel vasculitis is represented by Weyers granulomatosis, which is usually the first to involve the upper respiratory tract and can also have pulmonary and renal lesions.