Allopurinol-Induced Stevens-Johnson Syndrome: A Case Report

Abstract

Introduction: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare, severe, and potentially fatal mucocutaneous drug reactions, with mortality reaching up to 50% in the most extensive forms. Allopurinol is among the most frequently implicated triggers and is strongly associated with the HLA-B*58:01 allele. Patient information: We report the case of a 42-year-old man with asymptomatic hyperuricemia who had started allopurinol 21 days before symptom onset. He developed fever, malaise, a painful rash with atypical target lesions, flaccid bullae, and oral, ocular, and genital mucosal involvement, with epidermal detachment of 8% of the total body surface area. SJS was diagnosed clinically and confirmed by skin biopsy; the admission SCORTEN score was 2 points. Management included immediate discontinuation of allopurinol, intensive care unit admission, fluid resuscitation, analgesia, intravenous immunoglobulin, and multidisciplinary mucosal care. The patient improved favorably, with complete re-epithelialization at three months and only mild residual dry eye. Conclusion: Early recognition of SJS, prompt identification and withdrawal of the causative drug, and the best multidisciplinary supportive care are decisive for prognosis. Documenting the reaction and permanently contraindicating allopurinol are essential to prevent re-exposure.