Diffuse dermal neutrophilia in urticaria.

Twenty-three cases of diffuse dermal neutrophilia and urticaria were reviewed. Evidence of vasculitis or other disease was not present. Direct immunofluorescence was done in 19 cases and was positive but nonspecific in 14. The presence of angioedema (10 cases), dermographism (2 cases), atopy (4 cases), drug reactions (6 cases), and infections (6 cases) was similar to that seen in cases of urticaria without diffuse dermal neutrophilia. Nearly 9% of the cases of urticaria show this histologic pattern, and when cases of neutrophilic urticaria are added, 15.8% of cases of urticaria were found to show a major neutrophil component in the inflammation. In urticaria, neutrophilia may be part of an intense stimulus response pattern.