Allergic purpura is mostly seen in children, more males than females. The first symptoms are mainly skin purpura, and in a few cases, abdominal pain and renal symptoms appear first, and there can be different combinations of symptoms. 1, skin purpura: repeated skin purpura is the main manifestation of this disease. The skin purpura is the main manifestation of the disease. The scattered distribution of pinpoint to soybean-sized petechiae, petechiae, but also erythema, maculopapular rash, blistering or windbag-like damage, the lesions gradually fade after about 1-2 weeks, but can recur in batches, some can last for several years. Mostly seen on the distal extremities, especially on the extensor side of the lower legs, and when the lesions are extensive, they can spread to the upper extremities and trunk. It may be accompanied by urticaria and angioneurotic edema. In severe cases, purpura may fuse into large blisters with hemorrhagic necrosis. 2. Gastrointestinal symptoms: About 2/3 of children have gastrointestinal symptoms, usually within 1 week of purpura, some cases occur before the appearance of skin purpura (easily misdiagnosed). Recurrent paroxysmal abdominal cramps, nausea, vomiting, vomiting blood and blood in stool can be complicated by intussusception, intestinal obstruction, intestinal perforation and hemorrhagic small bowel inflammation. 3. Joint symptoms: About 1/3 of the children have painful swollen knees, ankles, elbows, wrists and other joints with restricted movement. It is transient and disappears within a few days without leaving joint deformity. 4, renal manifestations: domestic reports about of the children appear kidney damage. It often appears in purpura, but it can also appear after the purpura disappears or during the resting phase of the disease. Hematuria, proteinuria and tubular pattern, with increased blood pressure and swelling, a few show nephrotic syndrome, and occasionally acute renal failure. 5, other symptoms: central nervous system lesions are one of the potential threats of the disease, occasionally intracranial hemorrhage may occur, leading to apathy, irritability, even convulsions, paralysis, coma, aphasia; intra-muscular, sub-conjunctival and pulmonary hemorrhage, recurrent epistaxis, gum bleeding, myocarditis, pericarditis and testicular inflammation may also occur.