Cyanotic vasculitis is characterized clinically by purpura and necrosis on the lower legs and ankles, with ivory-white atrophic spots remaining after healing. Cyanotic vasculitis is a vasculitis disease in which polymorphic skin damage occurs on the basis of small vascular lesions in both lower extremities, leaving atrophic scarring after healing. It mostly occurs in young and middle-aged women. Most cases are aggravated in summer and reduced in winter, but the opposite is rarely true. Western medicine commonly used dipyridamole, intestinal soluble aspirin, vitamin E and Chinese herbal medicine Leigengtang and Danshen also have some effect on cyanotic vasculitis. Early diagnosis, early treatment, search for the pathogen as much as possible and carry out the cause-specific treatment. Not long ago, a 13-year-old female patient, Wen, was seen with dark red papules, nodules, and partial ulcers on both lower extremities, with self-conscious pain. She had been treated with hormones and other drugs in a western hospital, but the effect was not obvious, so she sought treatment from a Chinese doctor. Through dialectical analysis, I thought the disease was due to damp-heat injection, damp-heat with silt, blocking the meridians, and the prescription used Si Miao San plus Dan Shen, Papaya and Cuscuta, taking 10 pairs, but the effect was not satisfactory. The second consultation was changed to Wuling San and Ligustrum Efficacy Elixir, with external application of Qing Dai San and sesame oil, and there was a significant improvement after taking 10 pairs; the third consultation was changed to Ligustrum Efficacy Elixir and Liu Wei Di Huang Tang, and the patient was basically cured. The patient was instructed to take 20 more doses to consolidate the effect.