Persistent Liver Manifestations in Allopurinol-Induced Sweet's Syndrome: An Uncommon Case Report

Background/Objectives: Sweet's syndrome (SS), also known as acute febrile neutrophilic dermatosis, is a rare inflammatory skin disorder that may also present with extracutaneous manifestations. Liver involvement is thought to result from sterile neutrophilic infiltration, mirroring the skin pathology and highlighting the syndrome's systemic inflammatory nature. Timely recognition, exclusion of infectious or autoimmune etiologies, and prompt corticosteroid therapy are critical for favorable outcomes. Methods: Herein, we present the case of a 73-year-old man with hyperuricemia who developed both cutaneous and systemic manifestations of SS seven days after initiating allopurinol treatment. His symptoms included fever, conjunctivitis in the right eye, and painful, non-pruritic erythematous plaques, some with pustules, on the lower limbs, palms, and face. Results: Initial laboratory investigations revealed neutrophilic leukocytosis, elevated inflammatory markers, and renal and hepatic dysfunction. Empirical treatment with antibiotics and antivirals failed to improve his condition. The patient discontinued allopurinol and initiated a high-dose corticosteroid regimen, leading to rapid resolution of fever and improvement in skin lesions. Laboratory parameters gradually normalized, except for persistent high liver enzymes. A comprehensive diagnostic workup ruled out infectious, autoimmune, and malignant causes. Imaging studies, including CT, MRI, and MRCP, showed no structural liver abnormalities. Skin biopsy findings were consistent with SS, demonstrating dense neutrophilic infiltrates in the reticular dermis and papillary dermal edema. After his discharge, he was followed up by the Hepatology unit. The patients' liver enzyme levels normalized within three months with no recurrence or late complications one year later. Conclusions: In the context of drug-induced SS, persistent hepatic abnormalities, although rare, may occur in patients without underlying liver disease.