Persistent urticaria is generally defined as urticaria that meets the diagnostic criteria for chronic urticaria and is not responding well to treatment. Urticaria is mainly characterized by itchy, edematous erythema or wheals of the skin, which usually subside completely within 24 hours and leave no traces after subsiding. When the duration of urticaria lasts longer than 6 weeks, the diagnostic criteria are called chronic urticaria. If, after 2 weeks of treatment with a regular dose of a second-generation antihistamine, the treatment remains ineffective and the symptoms persist, with multiple weekly episodes of wheals and itching, the condition is called intractable urticaria. The causes of intractable urticaria are generally varied, and may be related to allergies to food, pollen, and medications; infections, stress, and hot and cold stimuli; as well as hereditary and immune factors. If the symptoms of urticaria are not relieved, or accompanied by other symptoms, you should go to the hospital in a timely manner, to identify the cause and then give targeted treatment.