[What is neutrophilic urticaria?]

Some debate continues to surround the existence of neutrophilic urticaria (NU) as a nosological entity. Certain authors consider NU as a banal form of urticaria since an infiltrate predominantly made up of polynuclear neutrophils (PNN) is seen in certain cases of chronic and acute urticaria. Moreover, it has been stated that the histological appearance of chronic urticaria varies according to the time between appearance of the plaque and the performance of biopsy: the presence of PNN may occur later. According to the literature, there appear to be no specific clinical characteristics associated with the presence of PNN at histology. Most cases exhibit moderate laboratory inflammatory syndrome. Data concerning therapeutic response are contradictory: some studies have shown no significant difference in terms of therapeutic response in relation to banal urticaria, while only one study has demonstrated superior response to dapsone in the case of histologically demonstrated neutrophilic infiltrate. There does not appear to be any disease more frequently associated in the event of NU. In conclusion, the available data concerning NU are insufficient to confirm the existence of this condition. A prospective study comparing routine acute and chronic urticaria biopsies would be extremely useful to better characterise the relationships between cellular infiltrate and therapeutic response.