Drug-allergic purpura is a purpuric drug-type dermatitis caused by oral, sedentary, and topical medications that cause petechiae and ecchymoses, which do not fade when pressed, and can occur on the limbs, hands and feet, and in severe cases, on the trunk. In clinical treatment, if the rash is densely distributed, it is necessary to intravenous compound glycyrrhizin injection, combined with olopatadine hydrochloride tablets orally, to strengthen the effect of anti-allergic, immunomodulatory treatment, but also with the external use of glycyrrhizin lotion or menthol lotion. During the treatment period, we should avoid reapplying allergy-causing drugs, and at the same time, patients are advised to avoid drinking alcohol and eating spicy and irritating foods, including raw onion and garlic.