Simple allergic purpura is a type of allergic purpura characterized by a predominantly cutaneous purpura. Allergic purpura is a common vasculopathic disorder with a certain genetic predisposition. It can be categorized according to the site of lesion into simple type of purpura, abdominal type of purpura, joint type of purpura, renal type of purpura, and mixed type of purpura. Simple purpura is the most common type, which mainly manifests as skin purpura, limited to the limbs, and lower limbs, buttocks are more common, while the trunk is less involved. Purpura varies in size, and the lesions are usually dark red in the early stages of the disease, do not fade when pressed, and can be fused into a piece, and with the development of the disease, it can gradually turn into purple, yellow-brown, and light yellow. Purpura is often repeated in batches, symmetrical distribution, some patients may be accompanied by skin edema, urticaria and so on. Once the symptoms of suspected purpura appear, patients need to go to the regular hospital, relevant examination, once diagnosed, should actively cooperate with the doctor to take therapeutic measures, such as the use of prednisone acetate, loratadine and so on.