I. Domestic diagnostic criteria Clinical manifestations: 1. 1-3 weeks before the onset of the disease, there are often symptoms such as low fever, sore throat, upper respiratory tract infection and general malaise. 2.Papular purpura with symmetrical distribution and varying size mainly appears in the vicinity of large joints of lower limbs and temple batches, which may be accompanied by urticaria or edema and polymorphic erythema. 3, the course of the disease can have hemorrhagic enteritis or arthralgia, a few patients abdominal pain or arthralgia can occur 2 weeks before the appearance of purpura, often with purpura nephritis. 4, laboratory tests platelet count is normal, platelet function and clotting time are normal. 5, histological examination of the affected area of the skin dermis around the small blood vessels neutrophil aggregation, blood vessel wall may have focal fibrous necrosis, epithelial cell hyperplasia and red blood cell exudation outside the blood vessels. Immunofluorescence examination shows that the vasculitis lesion has IgA and complement C3 deposition in the dermal vascular wall. 6, can exclude other diseases causing vasculitis such as cold globulin syndrome, benign hyperglobulin purpura, circumferential capillary dilated purpura, pigmented purpura mossy dermatitis, etc. The diagnosis can be confirmed if the clinical manifestations are consistent, especially non-thrombocytopenic purpura with palpable typical rash, and if other types of purpura can be excluded. If the differential diagnosis is really difficult, pathological examination can be performed. The American College of Rheumatology 1990 diagnostic criteria are as follows: 1, the first onset of the disease at the age of 20 years or less. 2, purpura purpura above the skin surface, can be felt. Purpura is not due to thrombocytopenia. 3, Gastrointestinal bleeding black stool, blood stool, positive stool occult blood test. 4, Pathology shows diffuse small vessel perivasculitis with neutrophil accumulation around the vessels. The diagnosis can be made if two or more of the above items are present. The criteria for efficacy are as follows: 1. All symptoms disappear after treatment, and the relevant examination is normal. Those who have not relapsed after one year of observation can be regarded as clinically cured. Compared with the untreated or other treatments, the time required to achieve healing is significantly shortened, and the incidence of complications and the recurrence rate within one year are significantly reduced. 2, effective treatment after the disease significantly improved, but not back to normal can be considered as clinical improvement, compared with the untreated group to achieve this degree of time required to significantly shorten, can be considered effective. If the treatment is cured but relapsed within two months, it can be regarded as effective in the near future. 3.Ineffective, there is no significant difference in the degree of improvement and time required after treatment compared with the untreated group.