Previous reports have suggested that the etiology of chronic urticaria/angioedema (greater than 6 weeks) can be identified 10% to 30% of the time while few reports have addressed the natural history of chronic urticaria/angioedema. An analysis of all patients referred to the authors’ practice between 1983-1985 with a diagnosis of urticaria/angioedema was performed. Patients with hereditary angioedema were excluded. Eighty-six of the 214 patients had chronic urticaria/angioedema. In the remaining 128 cases of acute urticaria there were four exercise induced, nine contact, six cold induced, six drug induced, 11 food induced, one viral hepatitis associated, 29 with dermographism, and 62 undetermined. An etiology could not be determined in any of the patients with chronic urticaria/angioedema. Laboratory tests, including CBC, chemistry panel, urinalysis, ANA, rheumatoid factor, complement studies, sedimentation rate, and skin tests were all noninformative. Chronic angioedema without urticaria occurred in only nine cases, 31 cases had chronic urticaria alone, and 46 cases had both chronic urticaria and angioedema. Of the patients followed over the 3-year period, 27 resolved while 48 continued to have urticaria/angioedema. Response to medications was variable and will be discussed. Our study suggests that an etiology is determined in much less than 10% of patients with chronic urticaria; fortunately, 32% of our cases resolved over a 3-year period
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