The causes of urticaria are complex and are categorized as exogenous or endogenous depending on the source, e.g. physical factors, food, drug implants, chronic infections, etc. Acute urticaria usually cause can be clear, chronic urticaria is difficult to specify. 1. Exogenous factors: common physical factors such as friction, pressure, heat and cold, sun exposure, etc., food such as animal proteins, fish, shrimp, eggs, fruits, mango, alcohol, etc., food additives, drugs such as penicillin, sulfonamides, various vaccines, codeine, aspirin, etc., implants, such as artificial joints, cardiac valves, orthopedic nails and so on. 2. Endogenous factors: often persistent role, common causes are chronic insidious infections such as bacterial, fungal, viral, parasitic infections, fatigue, vitamin D deficiency or mental stress, as well as rheumatic fever, systemic lupus erythematosus, thyroid disease and so on. It is recommended that patients with suspected urticaria should go to the hospital in time for timely diagnosis and treatment under the guidance of the doctor.