It is a relatively common microvascular allergic hemorrhagic disease. It is caused by infections, food allergies (e.g. fish, shrimp, crab, etc.), drug allergies (penicillin, streptomycin, sulfonamides, salicylates, pautazone. Phenobarbital, estrogens, androgens, para-aminobutyric acid, isoniazid, etc.), and other factors such as cold, pollen, pollen, insect bites, etc., but the cause of allergy is often difficult to determine. It is more common in children and adolescents, and more common in males than females. There is often a history of upper respiratory tract infection 1 to 3 weeks prior to the onset of the disease. The manifestation is skin petechiae, mostly around the joints of lower limbs and buttocks, purpura is symmetrically distributed, usually fading within a few days, but can recur; patients may have gastrointestinal symptoms; joint pain; renal symptoms, such as proteinuria, hematuria, etc., mostly seen in children. Clinical manifestations A. Prodromal symptoms Before the onset of the disease, there are often cold symptoms such as: low-grade fever. Sore throat, upper respiratory tract and general discomfort, etc. B. Typical symptoms and signs (1) Skin symptoms: The main symptom is symmetrical distribution of maculopapular purpura of different sizes near the large joints of the lower limbs and buttocks in batches, recurrent on the buttocks of the limbs, a few involving the face and trunk lesions initially with pruritus, small urticaria, angioneurotic edema and polymorphic erythema. (2) Joint and muscle symptoms: there may be single or multiple wandering joint swelling and pain or arthritis, and sometimes local muscle pressure pain. (3) Gastrointestinal symptoms: About 2/3 of patients may have mainly abdominal paroxysmal colic or persistent dull pain, accompanied by vomiting, vomiting blood or blood in the stool in severe cases of bloody stools. The clinical term is abdominal type. (4) Renal symptoms: usually appear around 2 to 4 weeks after purpura with carnal hematuria or microscopic hematuria proteinuria and tubular urine, also may appear after the rash subsides or during the disease quiescence. Recovery usually occurs within a few weeks in severe cases with hyperalgesia, azotemia and hypertensive encephalopathy. In rare cases, hematuria proteinuria or hypertension may persist for more than 2 years. The clinical term is renal type. Treatment 1.Try to remove the allergic factors. 2.Simple cases can be treated with compound rutin, calcium, vitamin C, antihistamine preparations. 3, fever and arthritis available corticosteroids, but can not stop the kidney invasion, for recalcitrant chronic nephritis can add free inhibitors. 4, Chinese medicine: according to the clinical symptoms of the disease dialectical treatment. Medical advice 1, pay attention to rest, avoid strain, avoid mood swings and mental stimulation. Prevent insect bites. Remove possible allergens. 2. Pay attention to keep warm and prevent cold. Control and prevent infection, use sensitive antibiotics when there is a clear infection or foci of infection, but avoid the blind prophylactic use of antibiotics. 3, pay attention to diet, because most of the allergic purpura is caused by allergens, should be prohibited Raw onion, raw garlic, chili, alcohol and other irritating food; meat, seafood, should avoid contact with pollen and other allergens.