In the clinic always encounter many patients think they have vasculitis, because patients have heard that severe vasculitis can lead to amputation and thus disability. In fact, after the doctor’s examination or some auxiliary examination, found that only a very small number of patients for the real vasculitis, the majority of the other is not vasculitis! But other vascular diseases. Then the real so-called vasculitis in the end is a kind of disease? The usual clinical term for vasculitis is “thrombo-occlusive vasculitis”, also known as Buerger’s disease. It is an aseptic inflammation of blood vessels of unknown origin, mostly seen in young and middle-aged people who smoke heavily, and is more common in the north, so the disease is related to smoking and cold. Newer studies have found that thrombo-occlusive vasculitis is also associated with a hypercoagulable state of the blood and autoimmunity. Vasculitis is generally clinically divided into three phases, namely, local ischemic phase, dystrophic phase, and gangrenous phase. The pathology is segmental obstruction of small and medium-sized arterial vessels, resulting in insufficient blood supply to the limbs or other organs they supply, which in severe cases leads to necrotic ulceration of the limb and necessitates amputation to preserve life. At the beginning, the blockage of blood vessels is not very serious, and the symptoms are not obvious at this time. Once the blood vessel is completely blocked, the typical painful symptom – intermittent painful claudication – will appear. In other words, when the patient walks for a certain distance, the pain in the affected limb starts to increase, and the pain worsens when the patient continues to walk, and cramps occur in the lower leg forcing him to stop. After resting for a few minutes, the pain in the lower limb is relieved and the patient can continue walking again. After walking for a certain distance, the pain appears again. The degree of ischemia in the affected limb determines the length of the walking distance. When the artery of the affected limb is completely occluded and there is no collateral small vessel compensation, resting pain occurs, i.e. the pain in the lower limb does not stop even when the patient is at rest. This pain is more severe, especially at night. The pain can be aggravated when the affected limb is elevated and relieved when it is lowered. The patient often drapes the affected limb under the bed to relieve the pain. In severe cases, the limb forms an ulcer or necrosis (gangrene) forcing amputation. Some vascular diseases are easily confused with vasculitis. For example, lower limb atherosclerosis occlusive disease is an ischemic disease of the lower limb arteries caused by atherosclerotic plaque or thrombus formed on this basis, the lesion is a blockage of medium and large caliber vessels, the disease develops slowly, and its late symptoms are similar to vasculitis, but the treatment method and effect are significantly better than vasculitis. For example, artificial blood vessel transplantation can be used. In addition, varicose veins or superficial phlebitis of lower extremities is a venous system disease, which is not a system disease at all with vasculitis, and generally speaking, it will not lead to serious consequences such as amputation. Its treatment differs greatly from that of lower limb thrombo-occlusive vasculitis or lower limb atherosclerotic occlusive disease. Therefore, it is important to pay attention to the differentiation and patients should not be nervous and should go to the general surgery or vascular surgery department of the hospital.