Urticaria more than 20 days is not good, to go to the hospital dermatology department in time to find out the cause, follow the doctor’s instructions to adhere to the drug treatment. 1. Remove the causes and triggers: hives are mostly caused by allergies, such as drugs, food, inhalants, etc., more than 20 days is not good because still in contact with these allergens. First need to clarify the causative factors, and avoid re-exposure. 2. adhere to the drug treatment: hives 20 days is not good may be related to the use of drugs and other irregularities, such as unauthorized stop, increase or decrease the dose of drugs. The disease usually use antihistamines orally, including loratadine, cetirizine, or oral hormone drugs such as prednisone, dexamethasone, etc., but also can be combined with topical glycerine lotion, zinc oxide ointment and so on. It is recommended to use the drugs in strict accordance with the doctor’s instructions. When the above situation occurs, it is recommended to go to the hospital for consultation and treatment, and the medication should be used according to the doctor’s prescription.