Clinical, demographic, and histopathological profile of drug-induced cutaneous reactions in a Mexican tertiary hospital: a nine-year retrospective study

Abstract

Cutaneous adverse drug reactions (CADRs) represent a significant challenge in clinical practice due to their wide clinical spectrum, potential severity, and diagnostic complexity. Despite their clinical relevance, epidemiological data from Latin America remain scarce. This retrospective observational study aimed to characterize the clinical, demographic, and histopathological profiles of CADRs in patients evaluated over a nine-year period at a national tertiary care center in Mexico. Conducted at the Dermatology Department of the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ) between January 2015 and December 2024, data were collected from electronic medical records and histopathology reports, including patient demographics, suspected drugs, clinical presentations, histological findings, comorbidities, and severity. A total of 345 cases were analyzed. Maculopapular exanthema was the most frequent manifestation (37.4%), followed by lichenoid reactions (8.7%) and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) (7.2%). Severe reactions, such as Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), occurred in 3.8% of cases. Antibiotics, particularly vancomycin, sulfonamides, and beta-lactams, were the most commonly implicated drug class (24.9%), followed by allopurinol (17.1%). In 30.7% of cases, the causative drug could not be identified. Over 80% of patients had at least one comorbidity, predominantly chronic and hematologic conditions. This study provides a comprehensive overview of CADRs in a high-complexity clinical setting and underscores the need for enhanced pharmacovigilance, detailed drug histories, and early dermatological assessment. Findings support the implementation of targeted preventive strategies and individualized risk evaluations, particularly in vulnerable and polymedicated populations. Keywords: Drug hypersensitivity; Cutaneous adverse drug reactions; Pharmacovigilance; Epidemiology.