Sweet Syndrome Presenting to the Emergency Department as Febrile Neutropenia

Aim: Sweet syndrome is an acute febrile neutrophilic dermatosis classically characterized by fever, painful erythematous skin lesions, and neutrophilia. However, its presentation in the setting of neutropenia is rare and may mimic infectious conditions such as febrile neutropenia in the emergency department. This case aims to highlight the importance of considering Sweet syndrome in febrile neutropenic patients with atypical skin lesions and to emphasize the diagnostic role of early dermatologic evaluation and skin biopsy.Case Presentation: A 64-year-old woman presented to the emergency department with fever, dyspnea, generalized weakness, and painful skin lesions. Physical examination revealed erythematous bullae on the right wrist, an ulcerated and crusted erythematous plaque on the right breast, and an erythematous nodule with a black center on the right finger. Laboratory evaluation demonstrated pancytopenia, including leukocytes of 0.65 × 10³/µL and neutrophils of 0.01 × 10³/µL. The patient was initially evaluated as having febrile neutropenia, and broad-spectrum antibiotic therapy was initiated. Because of the atypical and persistent skin lesions, dermatology consultation was obtained, and a punch biopsy was performed. Histopathological examination showed dense dermal neutrophilic infiltration without vasculitis, confirming the diagnosis of Sweet syndrome. Further hematological evaluation revealed no evidence of an underlying malignancy. Her clinical findings regressed during follow-up, and she was discharged with oral and topical treatment.Conclusion: This case demonstrates that the absence of neutrophilia does not exclude Sweet syndrome. In febrile neutropenic patients presenting with painful, atypical, ulcerated, or bullous skin lesions, Sweet syndrome should be included in the differential diagnosis. Early dermatologic consultation and skin biopsy are essential to distinguish this condition from infectious mimics and to guide appropriate management in the emergency setting.