1, food: protein: fish, shrimp, crab, shellfish, eggs, dairy products, some animal meat (beef and lamb, etc.); plant or fruit: lemon, mango, plum, apricot, strawberry, pecan, cocoa, garlic, tomato, etc.; spoiled food (not fresh food decomposition to produce alkaline peptides can promote the release of histamine); processed foods: food additives can also cause urticaria. 2, drugs: allergic reactive (penicillin, sulfonamides, furazolidone, serum preparations, various vaccine preparations); direct prohistamine release (morphine, codeine, cocaine, quinine, aspirin, etc.); other drugs. 3.Infection: Occult infection is one of the important causes of chronic urticaria, including bacteria (Staphylococcus aureus is the most common), fungi, viruses (whistling virus, hepatitis virus, etc.), parasites, etc. 4, inhalants: pollen, animal feathers and dander, dust, smoke, aerosols, volatile chemicals, etc. 5, physical factors: friction, cold, heat, sunlight exposure, exercise, etc. 6, systemic diseases: rheumatic fever, systemic lupus erythematosus, thyroid disease, lymphoma, leukemia, infectious monopolycytosis, etc.