1, food: seafood, eggs, and some animal meat (beef, lamb, dog, etc.) plant or fruit (lemon, mango, plum, apricot, strawberry, pecan, cocoa, garlic, tomato, etc.); dairy products; spoiled food (not fresh food decomposition to produce alkaline peptides can promote the release of histamine); food additives. 2. Drugs: metabolic (penicillin, sulfonamides, vindazone, serum preparations, various vaccine preparations); direct promotion of histamine release (morphine, codeine, cocaine, quinine, aspirin, etc.); other drugs. 3. Infection: occult infection is one of the important causes of chronic urticaria, including bacteria, viruses, parasites, etc. 4. Inhalants: pollen, animal feathers and dander, dust, smoke, aerosols, volatile chemicals, etc. 5. Physical factors: friction, pressure, cold, heat, sunlight exposure, exercise, etc. 6. Systemic diseases: rheumatic fever, systemic lupus erythematosus, thyroid disease, lymphoma, leukemia, infectious nucleocytosis, etc.