Neutrophilic urticarial dermatosis (NUD) in probable adult-onset Still disease responding to anakinra.

Differential diagnosis of urticarial skin lesions not representing classic urticaria remains a challenge. Long-lasting nonpruritic urticarial plaques and the histopathologic finding of a dense infiltrate with neutrophil granulocytes are indicative for a rare entity within a group of diseases termed neutrophilic dermatoses. Here, we report a case of neutrophilic urticarial dermatosis characterized by nonpruritic urticarial skin lesions, histopathologic changes resembling Sweet syndrome, and simultaneous Still syndrome. After treatment with conventional immunosuppressives including systemic corticosteroids without disease control, the patient responded to anakinra therapy within days achieving complete remission of skin lesions and systemic symptoms including fever and high C-reactive protein.