Allergic rashes, which may refer to eczema, urticaria, drug rashes and so on. There are differences in the etiology and clinical manifestations of different types of allergic diseases. 1. Eczema: Eczema is an inflammation of the superficial dermis and epidermis, which is related to the combined effect of many internal and external factors. It leads to polymorphic damages such as erythema, papules, papules, scales, and mossy changes on the skin. 2. Urticaria: Urticaria may be related to food, drugs, infection, living environment and other factors. It usually causes skin eruptions with itching. 3. Drug rash: drug rash is usually related to drugs, drugs enter the body through oral, inhalation, injection and other ways, which may lead to inflammatory damage to the skin and mucous membranes, usually accompanied by systemic symptoms, and in severe cases, it can involve multiple systems and multiple organs. The clinical manifestations of different types of drug rashes vary. Due to the differences in clinical manifestations of allergic rashes, it is recommended to go to the dermatology department of the hospital in a timely manner to give targeted treatment to avoid further aggravation of symptoms.