Symptoms of patients with purpura allergic, simply put, is that the skin will appear petechiae, ecchymosis, usually the first two lower legs, often symmetrical distribution, pressure does not fade, petechiae, ecchymosis can gradually fade away, but will recur. Purpura can be accompanied by joint symptoms, such as joint pain, especially in the knee and ankle joints, and joint swelling. It can also involve the gastrointestinal tract, with vomiting, abdominal pain and gastrointestinal bleeding, etc. Purpura involving the gastrointestinal tract is usually treated with glucocorticoids. Purpura can also involve the kidneys and can present with proteinuria and hematuria. The prognosis of most cases of purpura is good, but in some cases, such as purpura nephritis, the patient does not recover and develops end-stage renal disease, which may eventually develop into uremia. Therefore, if you have purpura, you need to go to the hospital immediately for formal examination and treatment, so as not to delay the condition, leading to aggravation of the condition, or kidney damage, which is not conducive to the recovery of the condition.