Etoricoxib-Induced Fixed Erythema

Background: Fixed drug eruption (FDE) is a non-immediate, CD8+ T cell-mediated hypersensitivity reaction characterized by well-demarcated erythematous-violaceous plaques that recur at the same site after re-exposure to the causative drug. Although NSAIDs and antibiotics are the most common triggers, various other medications may induce FDE, and genetic susceptibility has been linked to specific HLA alleles. Methods: We conducted a clinical evaluation supported by patch testing, oral drug provocation, and assessment of therapeutic alternatives to identify the causative agent and confirm delayed-type hypersensitivity. Results: We report the case of a 53-year-old woman with essential hypertension, autoimmune thyroiditis, and renal lithiasis who developed well-demarcated erythematous plaques with central vesiculation and moderate pruritus on the dorsal hand and posterior calf approximately 8 h after ingestion of a 60 mg etoricoxib tablet. Patch testing was negative, while oral challenge confirmed etoricoxib-induced FDE; celecoxib was subsequently evaluated as a potential safe alternative. Conclusions: This case underscores the importance of an integrated diagnostic approach-including careful history, clinical examination, and confirmatory testing-to accurately diagnose delayed cutaneous drug reactions and to identify safe therapeutic options for patients.