Atypical Presentation of Sweet's Syndrome: A Case Report and Review of the Literature

Sweet's syndrome (acute febrile neutrophilic dermatosis) is an inflammatory condition characterized by the abrupt onset of erythematous, oedematous plaques or nodules and a dense neutrophilic dermal infiltrate. Although usually associated with fever and tender lesions on the face and upper extremities, its clinical spectrum is broad, and atypical presentations may pose diagnostic challenges. We report the case of a 50-year-old female patient who presented with an acute eruption of widespread, annular, erythematous, and oedematous plaques predominantly involving the trunk and extremities, accompanied by severe pruritus. The patient denied fever or other systemic symptoms. Laboratory investigations demonstrated marked leukocytosis with neutrophilia and elevated inflammatory markers. An extensive infectious, immunological, and malignancy workup was unremarkable. Histopathological examination revealed a dense neutrophilic dermal infiltrate with leukocytoclasia in the absence of true vasculitis, consistent with Sweet's syndrome. Direct immunofluorescence was negative. The patient reported a history of similar episodic eruptions over two decades, often temporally associated with respiratory infections. Systemic glucocorticoid therapy led to rapid clinical improvement and normalization of inflammatory parameters, with complete resolution at follow-up. This case highlights the clinical heterogeneity of Sweet's syndrome, demonstrating that prominent pruritus, truncal predominance, and afebrile presentation may occur. Recognition of atypical manifestations is essential to avoid misdiagnosis, particularly with urticarial or allergic disorders. Thorough evaluation for associated systemic disease and careful documentation of recurrent patterns remain crucial. Early histopathological confirmation and prompt initiation of appropriate therapy enable rapid disease control and favourable outcomes.