According to the characteristics of this disease, Professor Cai Bingqin combined the evidence with the disease and treated it in stages. He believed that in the acute stage, the treatment should be internal regulation of qi and blood and external clearing of dampness and heat, and formulated “Wu Cao Tang” with addition and subtraction. “In the chronic remission period, the treatment is to tonify the deficiency and consolidate the surface, accompanied by clearing heat and promoting dampness. Allergic vasculitis is an allergic disease caused by drugs or infections, mainly invading postcapillary veins and capillary collaterals in the dermis, involving small blood vessels in the skin, but also in other organs, causing multi-system lesions. The disease occurs mostly in young adults, and the prominent damage is cutaneous vasculitis, which can be healed in a few weeks in mild cases, but in severe cases, multiple organs can be damaged and even life-threatening. Professor Cai Bingqin has been engaged in the clinical work of combining Chinese and Western medicine in the treatment of peripheral vascular disease for more than 40 years, and has accumulated rich experience in the treatment of allergic vasculitis. Now summarized as follows. 1. Acute stage: Early stage of the disease or relapsing activity. Clinical skin vasculitis manifests as erythema, purpura, papules, petechiae, blisters, ruptured vesicles, exudate, burning pain, urticaria, etc. The lesions are acutely progressive and aggravated, and even hemorrhagic blisters or necrotizing dermatitis occur. The systemic condition is characterized by low-grade fever, weakness, muscle and joint pain, dry mouth and bitterness, yellow urine, dry stool, red tongue, thin yellow coating, and slippery pulse. Laboratory tests may show accelerated blood sedimentation and elevated C-reactive protein values. Professor Cai Bingqin believes that this period is mostly a mixed evidence of deficiency and reality, such patients are immune diseases, internal imbalance of qi and blood; and external manifestations of blisters, ulceration, oozing, pain and even local skin necrosis in the lower leg area, which is a manifestation of internal invasion of evil toxins and damp-heat infiltration; therefore, treatment should take into account both the symptoms and the root cause, internal and external treatment, internal regulation of qi and blood, external clearing of damp-heat, self-developed “Wu Cao Tang “(Xi Cao, Zi Cao, Xian He Cao, G Datu Cao, Dry Lotus Cao) plus and minus. 2. Chronic remission phase: In this phase, the lesion activity disappears and the disease improves and remits or turns chronic. Clinical skin vasculitis manifestations gradually stabilize, ulcers gradually heal, systemic symptoms can be seen as tiredness and weakness, spontaneous sweating, fear of cold, etc.. The tongue is light red, the coating is white or yellow, the pulse is thin or moist, and laboratory tests such as blood sedimentation and C-reactive protein return to normal. Prof. Cai Bingqin believes that skin surface disease is prolonged and depletes the vital energy over time, and the pathogenesis is a mixture of deficiency and reality, with more deficiency and less reality, and the surface deficiency is not consolidated. The treatment is to nourish the deficiency and consolidate the surface, together with clearing heat and relieving dampness, by combining Yu Ping Feng San with “Wu Cao Tang” plus reduction. Typical case: Liang××, female, 15 years old, was admitted to hospital with “recurrent painful swelling and ulceration of both lower legs and both feet for more than 3 months”. At the time of admission, the patient was clear, in general spirits, no fever, slightly swollen calves and feet, with scattered ulcers and some crusts, the larger of which was located on the back of the left foot, about 1×5 cm in size, with yellowish pus flowing out, slightly high skin temperature, sometimes more painful, visible skin pigmentation, stomach and appetite, poor sleep, stool regulation, light red tongue, thin yellow coating, thin pulse. Auxiliary examination: blood WBC: 12.98×10E9/L, neutrophil percentage: 77.0%, lymphocyte percentage: 15.7%, platelet count: 428×10E9/L; immunoglobulin IgM: 37.6g/L, complement 4: 0.62g/L, total complement CH50: 49.0u/ml. This patient has been in remission for 3 months and the disease is chronic. The clinical manifestation is a mixture of deficiency and actuality, and the diagnosis is a deficiency of vital energy and damp-heat injection. The formula: Astragalus membranaceus (Astragalus membranaceus) 25g, Fructus Anemarrhena 15g, Atractylodes macrocephala 10g, Plantago ovata 15g, Poria cocos 30g, Cyperus rotundus 30g, Compositae purpurea 15g, Gutu grass 15g, Dry Lotus grass 10g, 10g Cyperus rotundus, 1 dose/day, decoction with water. At the same time, the patient was given Chinese herbal footbath with the following formula: 30g of rhubarb, 30g of tiger scepter, 30g of honeysuckle, 30g of dandan bark, 1 dose/day, footbath with water decoction. After 7 doses, the patient was in good spirits, the swelling of both lower legs and both feet was significantly reduced, the skin pigmentation, the ulcers did not have obvious exudation, most of them healed, the skin temperature was basically normal, there was no chills and fever, sleep was possible, and the stool was regulated. After taking 7 more doses, the swelling of both lower legs and feet subsided and the ulcers healed and the patient was discharged. The patient was discharged from the hospital after 7 doses, the swelling of both lower legs and both feet subsided, and the ulcers healed. The patient was given 1 pack of Chinese medicine Yu Ping Feng granules, tid, for 1 month to consolidate the disease. This disease is also seen in the Chinese medicine “plum kernel Dan”, “yellow loach carbuncle”, “pulse paralysis” and other diseases. Allergic cutaneous vasculitis is caused by allergic reactions, and there are many causes of vasculitis, including infection, allergic reactions, and physical and chemical factors. The clinical manifestations are mainly erythema, papules, blisters, nodules, superficial ulcers and other polymorphic skin damage, which may be accompanied by pruritus and painful symptoms, starting from the lower limbs. Western medical treatment is currently mainly the application of hormones and cytotoxic drugs, with obvious side effects, and the disease is prone to recurrence. ”Five herbs soup”, has obvious clearing heat and detoxification, anti-inflammatory and anti-swelling effects. Among them, g Datura can promote wind-dampness, open meridians and facilitate joints. Modern research also believes that g Datura contains alkaloids such as g Daturin and g Daturigenin, which have anti-inflammatory and better analgesic effects; Ming medical scientist Miao Xiyong believes that “Xi Cao, the key medicine for moving blood and cooling it, is also”. Comfrey root contains a variety of hydroxyanthraquinone derivatives, which can inhibit the permeability of the skin connective tissue of rats and has anti-inflammatory effects. Comfrey root contains naphthoquinone derivatives such as comfreyin, which has anti-pathogenic microbial effects and anti-inflammatory effects. The Compendium of Materia Medica considers that it has the following effects: “treating rash and pox, invigorating the blood and cooling the blood, and benefiting the large intestine”; the whole herb of Cyperus rotundus contains cyperin, which has anti-inflammatory and analgesic effects. It is cold, sweet and sour in taste, and has the effect of nourishing Yin, benefiting kidney, cooling blood and stopping bleeding, and contains many kinds of alkaloids, which can enhance immune function (humoral and cellular immunity). Professor Cai Bingqin believes that the rash is mostly related to superficial deficiency and lack of solidity of the lung guard. It is said in the “Treatise on Coughing” that “the skin and hair are the combination of the lungs, and the skin and hair are subjected to evil qi first, and the evil qi comes from its combination.” Therefore, the first thing to do is to benefit the guard and fix the surface, so that the skin and hair can be nourished and the evil wind can be protected. Yu Ping Feng San is derived from the book “Dan Xi Xin Heng” by Zhu Zhenheng. Zhu Zhenheng’s “Danxi Xinfa”. It is said that “the combination of Yu Ping Feng is less and more precise, and Qizhijiao and Fang Feng are the best. Yu Ping Feng San may enhance the immunity of patients by restoring the T-lymphocyte subpopulation in their blood and promote recovery from the disease. Therefore, the application of Yu Ping Feng San in the treatment of allergic cutaneous vasculitis can benefit the Qi and consolidate the surface, consolidate the therapeutic effect and prevent recurrence.