It is a common misnomer and misconception that people generally refer to vascular disease collectively as vasculitis. Vasculitis, short for thrombo-occlusive vasculitis (TAO), is an inflammatory and occlusive disease that primarily affects the blood vessels of the extremities. Vasculitis is most commonly seen in Asia and is more common in young and middle-aged men and less common in women. It mainly involves the middle and small arteries and veins of the extremities, with the lower extremity vessels being the main ones. It occurs throughout China, but is more common in the north. TAO patients are almost all young and middle-aged men, female patients are very rare, domestic and foreign literature reported that the incidence of female TAO is only 1-3%. 80%-95% of TAO patients have a history of smoking. Tobacco contains nicotine, which can cause small blood vessels to spasm and produce vascular damage. It causes ischemia of the limb resulting in pain or gangrene of the extremity. The pathogenesis is due to a persistent state of vascular spasm, which affects the trophoblastic vessels of the blood vessels themselves, causing relative ischemia of the vessel walls, secondary to inflammatory reactions and thrombosis, constituting the onset and development of TAO. TAO is an autoimmune disease. The disease is common in cold northern regions, with a high incidence during the cold season, and many TAO patients have a history of chilling. Cold freezing can cause vasoconstriction. The pathology of this disease is characterized by lesions mainly invading small and medium-sized arteries first, and then involving veins. The lesions are characterized by non-suppurative inflammation of the entire vascular wall, extensive fibrosis of the vascular wall and surrounding tissues in the later stages of the disease, and the lesions are segmental in nature, and the collateral circulation is gradually established while the vessels are occluded. Pathological process etiology, vascular stiffening and narrowing, thrombosis, luminal obstruction, thrombotic mechanization, limb ischemia, vascular recanalization, and ulcerative necrosis. Vasculitis and varicose veins are two completely different diseases, the latter is due to venous blood reflux, increased pressure in the veins caused by venous tortuous expansion, can lead to lower limb pigmentation, ulcers (old rotten legs), etc., but its harm is much lighter than vasculitis, generally does not lead to amputation.