An atypical persistent eruption of adult-onset Still's disease with neutrophilic urticarial dermatosis-like dermal features: A case report and review of the literature

Adult‐onset Still's disease (AOSD) is a rare systemic inflammatory disorder with unknown etiology. Cutaneous manifestations of AOSD could be typical (evanescent maculopapular rash, salmon‐pink, and non‐ or mildly pruriginous) or atypical (persistent lesions with pruritus). In typical AOSD, microscopic assessment shows non‐specific features such as very mild dermal inflammatory infiltrate (lymphocytes and neutrophils), and in atypical AOSD, it shows highly suggestive dyskeratotic/necrotic keratinocytes with neutrophilic and lymphocytic dermal infiltrate.1-3 Neutrophilic urticarial dermatosis (NUD) is an autoinflammatory condition recently described as recurrent urticarial eruption vanishing within 24 hours with histologically marked neutrophilic infiltrate and leukocytoclasia. NUD is a rare cutaneous presentation of AOSD.4 We report two cases of atypical persistent eruption of AOSD with dyskeratotic/necrotic keratinocytes and in one case leukocytoclasia (as an NUD‐like dermal pattern) that has rarely been described previously. Knowledge of the clinico‐pathological spectrum of atypical AOSD should facilitate diagnosis of this rare and severe disease