Usually, the causes of hives include food allergies, use of drugs, bacterial and viral infections, and physical factors. 1. Food allergy: such as fish, shrimp, crab and other animal proteins, mango, lemon, onion, garlic and other plant foods, sulfites, lemon yellow, salicylates and other food additives, etc., may cause urticaria. 2. The use of drugs: such as penicillin, sulfonamides, serum preparations, various vaccines, etc., part of the population in the use of allergies may be triggered, which leads to the emergence of urticaria. 3. Bacterial viral infections: such as hepatitis virus, upper respiratory tract viral infections, staphylococcus aureus infections, etc., may lead to urticaria. 4. Physical factors: such as friction, heat, cold, sunlight and other physical factors, may induce urticaria. In addition, environmental, endocrine, disease factors, may also lead to urticaria. It is recommended that the patient should consult a doctor for examination in a timely manner and clarify the cause of the disease under the guidance of the doctor in order to take corresponding treatment measures.