Allergic purpura is a special type of vasculitis and also a hypersensitivity disorder. It commonly occurs in adolescents and children aged 5 to 14, with a higher incidence rate in the spring and autumn seasons. The disease frequently relapses and cannot be completely cured. The most common causes of allergic purpura include infections, medications, and foods. Infections are the most frequent cause, such as bacteria, viruses, parasites, tuberculosis, etc. If it is merely a cutaneous form, no special treatment is required at this time, and bed rest alone can alleviate the condition. If there is the presence of blood or protein in the urine, and renal biopsy shows a large number of crescents, it then indicates a serious aggravation of the condition.