[Urticaria vasculitis].

Fifteen cases with suspected urticarial vasculitis which were seen during the last ten years at the Department of Dermatology in Hamburg were reviewed. The cases were reevaluated after strict formulation of criteria for vasculitis (fibrin in and around small vessels, leukocytoclasis of neutrophilic granulocytes, extravasation of erythrocytes) and discussed in the context of the international literature on urticarial vasculitis. The conclusion of our study is that urticarial vasculitis is often overdiagnosed clinically if persistent urticarial lesions occur that show some erythematous changes or a hint of hemorrhage. Furthermore, urticarial vasculitis is often overdiagnosed histopathologically because some cases of urticaria were found that presented with heavy infiltration of small vessel walls with neutrophilic granulocytes. In these cases extravasation of erythrocytes, fibrin in and around vessels and leukocytoclasis is always absent. In summary urticarial vasculitis seems to be a variation of leukocytoclastic vasculitis with less extravasation of erythrocytes and not, as frequently stated, and entity of its own.