Necrotizing Sweet syndrome: a new variant of neutrophilic dermatosis mimicking necrotizing fasciitis

Background: We report a series of patients initially given the diagnosis of necrotizing fasciitis whose course progressed despite surgical debridement, antibiotic therapy, or both, but who responded rapidly to systemic corticosteroids.

Objective: We sought to evaluate the clinical data, histopathologic and microbiology information, and treatment course of this unusual entity.

Methods: This was a descriptive study/case series.

Results: Three immunocompromised patients who presented with signs and symptoms of necrotizing fasciitis were included. They appeared septic, failed multiple courses of antibiotics, demonstrated pathergy, and two of them underwent extensive surgical debridement. None of the cases yielded a microbial source. Dermatologic consultation and histopathology confirmed deep Sweet syndrome in all cases, with marked necrosis of the soft tissue--including myonecrosis--in the two patients with debridement. All patients responded rapidly to high-dose systemic corticosteroids.

Limitations: To our knowledge, this is the first report of this unusual presentation; there are a limited number of cases.

Conclusion: We propose that these cases represent a new variant of neutrophilic dermatosis: "necrotizing Sweet syndrome," an acute necrotizing neutrophilic dermatosis. This subtype is also characterized by the rapid onset of progressive erythematous, warm, edematous cutaneous lesions with deep-tissue neutrophilic infiltration and soft-tissue necrosis, in the absence of infectious cause. Awareness of this entity and early dermatologic consultation is critical as debridement results in expansion of the process, resulting in additional and aggressive resection--a vicious cycle with significant possible morbidity.