It is a complication of varicose veins or superficial phlebitis, and can also be seen in post-deep vein thrombosis syndrome. It mostly occurs in patients who stand and walk with weight for a long time, accompanied by varicose veins of lower limbs, such as hairdressers, traffic police, salesmen, teachers, surgeons and other people who are engaged in long time standing and immobile occupations. The disease is recurrent, itchy and then painful, and then it breaks down to form a trauma; at the beginning of the disease, it may only be inflammatory exudation, and then ulcers occur, and the old does not get better, the bigger the rot, the deeper the rot, and finally the whole layer of skin rots off. The skin around the ulcer is affected, atrophy occurs, darkening, causing eczema, flaking from time to time, and feeling itchy. Once the ulcer occurs, the bone is exposed and the surface becomes infected, resulting in chronic osteomyelitis and, in serious cases, the risk of amputation; a few ulcers that do not heal for many years, with cauliflower-shaped wounds, are mostly signs of cancer. Many patients treat it as a skin disease, ointment layer after layer, prescriptions constantly changed, but the old rotten leg is ineffective for a long time, the old rotten, suffering from torture. What is going on? We all understand the truth that water flows downward, so how can the venous blood that flows to the bottom of the feet on the human body return to the heart? The venous blood in the lower extremities must overcome the great geocentric suction to return upward. The mystery is mainly the pressure difference between the artery and vein. The former pressure is high and the latter pressure is low, so the direction of blood flow naturally travels from high to low. In addition, there is the squeezing effect of muscle contraction when the lower limbs move, as well as the venous valves located inside the veins. Some people are born with weak vein walls, or the number of venous valves is too little, poor structure, poor function; if usually standing still, the lower limb muscle activity is reduced, the muscle squeeze effect is not enough, the lower limb venous blood flow back is blocked, causing the pressure in the veins to rise. After a long time, the superficial veins of the lower limbs expand and thicken, and then develop into convoluted clusters, like earthworms coiled under the skin. Patients often feel soreness and fatigue in the lower limbs, and some have edema in the back of the foot or ankle joint. If left untreated, the skin of the lower leg and ankle will become atrophied, thinner, shiny, darker, eczema, and even ulcers.