Urticaria, commonly known as urticaria and rubella, is a common allergic skin disease. It is caused by various factors that lead to temporary inflammatory congestion of the blood vessels of the skin and mucous membranes with a large amount of fluid exudation, resulting in localized edematous damage. It manifests itself as a red patch of various shapes and sizes, which occurs rapidly, with severe itching, and leaves no trace after fading. It can also be accompanied by fever, abdominal pain, diarrhea or other systemic symptoms. The causes of urticaria are complex and can be caused by a variety of endogenous or exogenous factors, generally common can be summarized as follows: 1, drug factors: many drugs can cause the disease, the most common are penicillin, cephalosporins, antipyretic and analgesic, flavopiridol, dysentery, sulfonamides, as well as serum preparations and certain vaccines. 2, food factors: can cause urticaria a variety of food, the most common of which contains special protein fish and shrimp, seafood, milk, beef and mutton, crabs, eggs, soy products, etc., certain insect food (such as silkworm chrysalis, golden cicada, bullfrog) is also a common causative factor, drinking alcohol is also a common cause of urticaria. 3, infection: bacterial infection, viral infection, fungal infection and parasitic infection in the body can cause urticaria. In addition, mosquitoes, mites, fleas, bedbugs and other bites can occur after papular urticaria. 4, inhalants: a variety of external inhalants may cause urticaria, such as various pollen, dust mites, cotton wool, animal fur, chemical gases, etc. 5, physical and chemical factors: such as hot and cold stimuli, sunlight, friction and pressure and other physical and mechanical stimuli or certain chemical substances into the body and the onset. 6, certain diseases: certain diseases can also lead to the occurrence of urticaria, such as various types of cancer, lymphoma, rheumatism, cholecystitis, nephritis, liver disease, gastrointestinal diseases, diabetes, chronic pharyngitis, dental caries, etc.