Clinical utility of testing for autoimmunity in chronic idiopathic urticaria

Background Positive autoimmune testing in patients with chronic idiopathic urticaria (CIU) has previously been associated with more severe disease. Objective We sought to determine whether patients with CIU and a positive autoimmune urticaria test finding were more difficult to treat clinically. Methods In this retrospective study, 428 patients seen by physicians of the Department of Dermatology, University of Pittsburgh between January 2007 and March 2010 were identified by International Classification of Diseases, Ninth Revision code 708.9 for urticaria. Included individuals met clinical criteria for CIU and had an autoimmune urticaria test (chronic urticaria index or CD203 expression test) result in their medical record. Results Twenty patients met the study criteria set forth and positive autoimmune urticaria test results occurred in 8 of the 20 patients. In all, 75% of patients in each group (positive and negative autoimmune test findings) were more than 75% clear of disease ( P = 1) by the last visit. Mean number of distinct medications prescribed for urticaria management in the positive and negative autoimmune groups was 6.9 and 8.4, respectively ( P = .4). No significant difference was detected between the various medications that led to more than 75% disease clearance in either group. The mean number of patient clinic visits over the study period was 3.1 and 4.8, respectively, for positive and negative groups ( P = .5). Limitations This was a retrospective study with a small sample size. Conclusion A positive autoimmune urticaria test finding in the setting of CIU is not indicative of a more complicated clinical course.