Neutrophilic urticarial dermatosis: an entity bridging monogenic and polygenic autoinflammatory disorders, and beyond

Neutrophilic urticarial dermatosis (NUD) has been described in 2009. Clinically, it is an eruption of rose or red macules or slightly elevated plaques, vanishing within 24 h. It occurs mostly on the trunk and the limbs. Extracutaneous signs such as fever or joint pain can be associated. The histopathological findings are a dense perivascular and interstitial infiltrate of neutrophils with leucocytoclasia but without vasculitis. It is often associated with other systemic diseases such as Schnitzler syndrome, adult-onset Still disease (AOSD), cryopyrin-associated periodic syndrome (CAPS) and Lupus erythematosus (LE). The pathogenesis of NUD is not well established but its association with CAPS and AOSD suggests that NUD is linked to autoinflammation. The management of NUD depends on the clinical findings and the potential associated systemic condition. Neutrophil migration inhibitors, such as dapsone or colchicine, and IL-1 antagonists, in particular, anakinra, are the main therapeutic options for the treatment of NUD. The prognostic value of NUD, especially when occurring in the setting of LE is not known and needs to be further investigated.