 Chronic urticaria is a common condition which can be debilitating, difficult to treat, and sometimes life-threatening. Approximately 15-25 of the population is affected by urticaria at least once in their lifetime, and chronic urticaria develops in more than 25 of these cases. Chronic urticaria is characterized by frequent, often daily, development of pruritic wheals of 6 weeks duration or longer. The average duration of chronic urticaria is 3-5 years in adults. In the majority of cases, an underlying trigger for the urticaria is not identified and these cases are referred to as idiopathic CIU. These considerations have led to the hypothesis that CIU may have an autoimmune etiology. 