A Case Report of Localized Bullous Sweet’s Syndrome Associated with Metabolic Syndrome

Abstract

Introduction: Bullous disorders constitute a heterogeneous group of dermatoses characterized by vesicles and bullae arising from diverse etiologies, including allergic, autoimmune, inflammatory, infectious, mechanical, and metabolic causes. In most cases, an accurate diagnosis can be established through a detailed history, careful clinical examination, and supportive histopathological findings. Bullous Sweet’s syndrome is a rare morphological variant of Sweet’s syndrome in which vesicles and bullae develop over tender erythematous plaques rather than as the typical edematous papules and nodules. This variant is clinically important because it closely resembles other vesiculobullous disorders, erythema multiforme, and drug-induced reactions. It is frequently associated with underlying hematological malignancies, necessitating comprehensive systemic evaluation. Herein, we report a case of localized bullous Sweet’s syndrome with underlying metabolic syndrome. Case Presentation: A 40-year-old woman presented with multiple painful, erythematous, fluid-filled lesions on both legs for 15 days, associated with swelling. She denied fever, joint pain, abdominal complaints, recent infection, oral or genital lesions, drug intake before lesion onset, or a history of underlying cancer. Dermatological examination revealed multiple erythematous, blanchable, tender papules and plaques of varying sizes, with overlying clear, tense vesicles and bullae on both lower legs. A few lesions had ruptured, forming erosions with hemorrhagic and necrotic crusts. The absolute neutrophil count (ANC) was elevated at 16,000 cells/µL, and the erythrocyte sedimentation rate (ESR) was elevated at 25 mm/h by the Westergren method. Fasting blood glucose (343 mg/dL) and HbA1c (13.1%) levels were markedly elevated. Predominant polymorphonuclear leukocytes were observed on Tzanck smear. Histopathological examination revealed a subepidermal cleft containing multiple neutrophils, a few eosinophils, and erythrocytes, along with a dense perivascular infiltrate of neutrophils and eosinophils and extravasation of erythrocytes in the dermis. The patient was started on oral prednisolone at a weight-based dose of 0.5 mg/kg/day and systemic antibiotics according to microbial culture and sensitivity results, with strict glucose monitoring. Despite a good response, dapsone 100 mg once daily, colchicine 0.5 mg twice daily, and doxycycline 100 mg twice daily were also administered for 5 weeks because of the deranged metabolic profile. After complete resolution of the vesiculobullous lesions, colchicine was discontinued; however, deep punched-out ulcers persisted, necessitating pentoxifylline 400 mg three times daily and thalidomide 100 mg twice daily, after explicit counseling and written informed consent, to facilitate healing. Conclusions: Bullous Sweet’s syndrome is rare and diagnostically challenging because it can mimic autoimmune, infectious, and drug-induced dermatoses. Although the literature commonly associates bullous Sweet’s syndrome with drug exposure or malignancy, this case highlights the possibility of an underlying asymptomatic metabolic syndrome. The disease also demonstrated an unusual localized distribution, with lesions confined to the lower legs rather than the typical generalized presentation.