The onset of urticaria is related to a variety of factors, such as food, infection, drugs and other factors. 1. Food: animal protein, plants, food additives, etc. can induce urticaria. 2. Infection: hepatitis virus, coxsackie virus, streptococcus, fungi, parasites and other infections can also induce urticaria. 3. Drugs: penicillin antibiotics, serum preparations, vaccines, etc. may also induce urticaria. The onset of urticaria is also related to pollen, animal dander, hair, dust mites, mental as well as genetic factors. The activation and degranulation of various inflammatory cells, such as mast cells, caused by all the above reasons cause the release of inflammatory mediators, such as histamine, resulting in vasodilatation and increase in permeability and increased secretion of glands, which causes urticaria. Urticaria patients in ordinary life should avoid contact with all kinds of substances or environment that may cause urticaria attack, urticaria should go to the hospital in time, under the guidance of the doctor as soon as possible to avoid further attacks.