D3.18 - Role of an Allergological Work-up in Antibiotic Allergy Delabeling in Mexican Pediatric Patients

False antibiotic allergy labeling is a global public health problem that limits first-line therapies and is associated with poorer clinical outcomes and increased healthcare costs. In Mexico, data based on formal allergy specialist evaluations remain scarce. This study aimed to assess the outcomes of an allergological work-up in pediatric patients with reported antibiotic allergies and to determine the proportion of confirmed antibiotic allergies.

A retrospective study included 53 pediatric patients with suspected antibiotic-related allergic reactions (ARAR) evaluated during 2025 at the Children’s Hospital Federico Gómez in Mexico City. Patients were identified during inpatient rounds or through consultations to the Allergy and Clinical Immunology Department. Collected variables included antibiotic agent and class, clinical indication, route of administration, prior exposure, clinical manifestations, and treatment. Based on clinical history, reactions were stratified as low or high risk. According to risk stratification, drug provocation tests (DPT) or skin-prick tests were initially performed as part of the allergological evaluation.

A total of 53 patients were evaluated; seven had more than one antibiotic allergy label. Beta-lactams were the most frequently reported group (66.12%), with ceftriaxone being the most commonly implicated agent, followed by macrolides and glycopeptides (9.6% each). The most frequent manifestation was maculopapular exanthema (41.93%), followed by erythema (16.2%). Upper respiratory tract infections were the most common indication (40.3%). Five patients (9.43%) classified as high risk underwent skin testing; only one test was positive, and the subsequent DPT was negative. Overall, 29 DPTs were performed; only one was positive and the reaction was mild. Antibiotic allergy labels were removed in 37 of 53 patients (69.8%) who completed the allergological evaluation, mainly after negative DPTs.

In accordance with current recommendations, initiating the diagnostic approach with oral challenges in pediatric patients classified as low risk based on clinical history is safe. This strategy enabled removal of the antibiotic allergy label in more than half of the patients and may facilitate access to first-line therapies. Active antibiotic allergy delabeling should be encouraged to improve patient care.