NEUTROPHILIC URTICARIA - CLINICAL-FEATURES, HISTOLOGICAL-CHANGES AND POSSIBLE MECHANISMS

Neutrophilic urticaria (NU) is a histologically defined entity, but it s clinical and pathogenetic aspects are poorly understood. We investig ated 22 NU patients whom we identified by examining lie biopsies of we als. The patients comprised 11 of 20 with acute urticaria, nine of 49 with chronic urticaria, one of 10 with cold urticaria and one of 10 co ntrols undergoing prick tests, Clinically, NU patients had a shorter m ean duration of disease than other urticaria patients and significantl y increased erythrocyte sedimentation rate and leucocytosis, Histologi cally, not only neutrophil counts, but to a lesser extent also eosinop hil counts and mononuclear ar cell infiltrates were significantly incr eased in lesional skin of NU, and there was more marked vasodilatation and endothelial swelling. On immunohistochemistry increased tumour ne crosis factor alpha and interleukin (IL)-3 expression was noted, compa red with other urticarias, whereas IL-8 expression was only minor. The se data characterize NU as an acute phase urticarial reaction associat ed with an intense inflammatory infiltrate and marked upregulation of some mast cell-derived cytokines.