Background: Common environmental allergens play a role in the pathogenesis of urticaria via type I hypersensitivity reaction. Changes in the number of eosinophils and serum IgE in circulating blood in various allergic disorders have been reported by several investigators. However, there are only a few reports about the measurement of those numbers according to a clinical type of urticaria. Objective: This study was undertaken to measure the peripheral blood eosinophil and serum IgE levels in 514 patients with different types of urticaria. Method: We measured the peripheral blood eosinophil and serum IgE levels in 514 patients who visited the Department of Dermatology, Kyungpook National University Hospital from November 1993 to December 1996. Of these patients there were 122 with acute urticaria (23.7%), 160 with chranic urticaria (31.2%), 164 with dermographism (31.9%), 11 with acute urticaria plus dermographism (2.1%) and 57 with chronic urticaria plus dermographism (11.1%). (continue...)(Korean J Dermatol 1999;37(4): 437-443)