A boy, 4 years old, with abdominal pain for 10 days, with nausea and vomiting, with constipation and black stool, was seen in the emergency room at 4:00 a.m. He said that he had been treated with anti-inflammatory therapy in the local hospital for 4 days, but the abdominal pain was not significantly relieved, and he came to the emergency room at night when the pain was really unbearable. The examination found pressure pain throughout the abdomen, but no manifestation of peritonitis, ultrasound found pelvic effusion, fecal occult blood ++++, high white blood cells. The pediatric abdominal purpura belongs to a kind of allergic purpura, mainly involving the small blood vessels of the gastrointestinal tract, causing small vascular metamorphosis, i.e. allergic reaction, usually often with allergic factors, such as protein, seafood and other foods, or a history of infection within half a month. The most common clinical manifestation is abdominal pain, usually accompanied by changes in bowel habits, blood in stool, nausea, vomiting, etc., rarely accompanied by vomiting blood, may be accompanied by skin purpura, joint pain, hematuria and other symptoms. The abdominal pain is persistent, usually located around or below the umbilicus, and is more intense. The treatment of this disease includes the following aspects: 1. general treatment, bed rest; 2. symptomatic treatment: antihistamine and calcium can be applied, antispasmodic in abdominal pain, gastrointestinal bleeding should be fasted, and intravenous cimetidine 20-4-mg/Kg per day. high-dose vitamin C, 2-5g/d; 3. hormone therapy; 4. anticoagulation: aspirin 3-5g/Kg per day, or dipyridamole 2-3mg/Kg, or apply heparin sodium drip; 5.Chinese medicine treatment. If there is hematuria and proteinuria, it means there is damage of kidney function, which means the prognosis is not good, and the change of kidney function should be observed at any time.