Purpura is a skin disease that mainly manifests as subcutaneous bleeding and most of them have the possibility of recurrence. Especially allergic purpura, because most of them may be due to the patient’s certain allergic reaction, the skin tissue of both lower limbs bleeds to form purpura. If purpura recurrence may cause certain kidney damage, so again certain proteinuria and other symptoms are formed. If purpura occurs, it also needs active treatment. In addition to allergic purpura, purpura may also be caused by other blood aspects, such as leukemia or thrombocytopenic purpura, etc. are possible.