Urticaria is prone to recurrence and is indeed very tricky. Always bad reasons, summarized below: First, hives is essentially an allergic disease, but the relevant allergens are very difficult to find, especially chronic urticaria, about half of the patients can not find a clear cause, resulting in hives lingering difficult to cure. The second factor is that many people have hives after the medication is very irregular, after the onset of the medication for a few days, the lesions subsided, this time forget to take the medication, stop taking it, and again relapsed, only to start taking it again, the cycle is repeated, irregular, irregular medication, is also the reason why hives are easy to repeatedly difficult to heal. Third, some hives may be combined with underlying diseases, such as autoimmune related diseases, the primary disease can not be solved, but also easy to cause hives repeatedly bad. Therefore, urticaria is prone to recurrence in clinical practice.