Most of the hives can not find a clear cause, the common causes are food factors, drug factors, infectious factors, physical stimulation, foreign body stimulation, systemic diseases and so on. 1. Food factors: such as certain animal proteins, as well as plants, food additives and so on. 2. Drug factors: antibiotics, certain serum products, vaccines, etc., which can easily cause allergies. 3. Infectious factors: various types of hepatitis, viral infections, fungal infections, parasites and so on. 4. Physical stimulation: such as external hot and cold temperature stimulation, sunlight stimulation, friction stimulation, and so on. 5. Foreign body stimulation: for example, pollen, animal fur, animal hair, and dust mites, paint and other stimuli. 6. Systemic diseases: such as systemic lupus erythematosus, endocrine disorders, immune thyroiditis, malignant tumors and other diseases. Urticaria may have other causes, need to go to the hospital dermatology consultation, improve the examination to clarify the cause of the disease, follow the doctor’s instructions standardized treatment.