Chronic urticaria and angioedema.

Of 231 patients evaluated for chronic urticaria and angioedema (CUA), 192 were diagnosed as having an idiopathic condition. The roles of serum IgE, complement (CH50), and immune complexes (IC) were investigated in 112 patients with idiopathic CUA. Immediate skin tests were not helpful, but total IgE was elevated in 13%, equally divided between dermographic (D) and non-dermographic (ND) patients. Depressed haemolytic complement (CH50) was noted in 10% of CUA, all of whom were D. Serum IC were elevated in 38% equally divided between D and ND patients. There was no relationship between depressed CH50 and elevated IC. Skin biopsies, evaluated by both light and immunofluorescent techniques, were negative for all specimens tested. The pathophysiology of idiopathic CUA is multifactorial, with a variety of immunological mechanisms involving serum IgE, CH50, and IC. . The relationship between depressed CH50 and dermographism was noted but unexplained by serum or tissue studies.