A 7-year-old boy, Xiao Han, just started elementary school this year and jumps to school every day. Recently, many students in the class had a cold and cough, and Xiao Han was not spared, alas, a small cold, a common disease, his mother gave him some small herbal medicines to clear the heat and send him to school again. However, what made mom and dad anxious was that yesterday, some purple rashes appeared on the front of Xiao Han’s calves, and at night, his legs and knee joints swelled up, and he also screamed from time to time that his stomach hurt. Now, the mother can be anxious, today, bring him to the hospital. The actual doctor has seen and tested the blood and urine, and it was diagnosed as allergic purpura. IgA, IgE, complement, and leukotrienes all play a major role in the development of the disease. The disease begins with purple palpable macules or patches, petechiae petechiae, and rarely blisters, macules, necrosis, and ulcers on the skin and mucous membranes. There is also fever, headache, malaise and loss of appetite. Occasionally, abdominal cramps and arthralgia may be the main manifestation or no skin damage may occur. Gastrointestinal symptoms can occur at any stage of the disease, with colic, vomiting, bleeding or intestinal paralysis or intussusception, or even intestinal perforation Joint involvement is a more common symptom, starting with diffuse arm and calf pain. Swelling around the joints and arthritis may subside within a few weeks without remaining deformed. Most children have renal involvement, manifesting as proteinuria and hematuria. about 1% of cases progress to end-stage renal disease. A small number of cases may be associated with Guillain-Barre syndrome and mononeuritis. Coughing up blood may occur in cases of pulmonary vascular involvement. Cutaneous symptoms often last 6-16 weeks, but 5-15% have a chronic course that can last several months to 1-2 years. Treatment usually involves treating infection, controlling allergies, protecting blood vessels and kidneys, and using a combination of herbs to activate blood circulation, remove blood stasis and eliminate blemishes. Early application of glucocorticoids can reduce kidney damage and provide timely relief of abdominal symptoms, but attention should be paid to the side effects of hormones and to avoid secondary viral and bacterial infections. Intravenous gammaglobulin can stop the rapidly progressive nephritis, which can shorten the cure rate, shorten the cure time and reduce the recurrence. Avoid seafood, beef and mutton, take rest and follow up on time.