Chronic urticaria can be defined as the occurrence of widespread daily or almost daily wheals for at least 6 weeks, which may be accompanied by angioedema. While the wheals are transient, the resolution of angioedema is slower than wheals and could take up to 72 hours. The natural course of chronic urticaria is self-limited, with spontaneous remissions and occasional relapses. The investigators calculated a 0.6% (95% CI(Confidence Interval): 0.4-0.8) prevalence in a population study. It has a great impact on patients' quality of life. In a recent national survey on patients attending Allergy Department, chronic urticaria was the disease with greater impact on mental quality of life out of all allergic diseases.