D1.396 - Drug hypersensitivity reactions in paediatric patients pre and post-liver transplant: a single-center study

Children undergoing liver transplantation (LT) are at increased risk of allergic disease; however, data on drug allergy in this population remain limited. We aimed to further characterise drug hypersensitivity in paediatric liver transplant recipients.

We retrospectively reviewed paediatric LT recipients at a single tertiary transplant centre from January 2020 to February 2025. Relevant data was extracted from clinical records including drug reactions, and food and environmental allergies. Drug allergy was defined as clinician-documented hypersensitivity reactions to medications. Contact dermatitis, infusion-related reactions, and drug side effects were excluded. Reactions were classified by culprit drug and reaction phenotype.

We identified 193 paediatric LT recipients (median follow-up 25 months). 29 patients (15%) had documented drug allergy, with 19 occurring post-transplant (19/29). Age at transplant was higher in patients with drug allergy (median 9.81 vs 3.01 years; p=0.0007) with a balanced gender distribution (15/29 male). Diagnoses included extra-hepatic biliary atresia (38%), acute liver failure (17%), chronic cholestasis (15%) and metabolic conditions (10%).

Antibiotics were the most frequently implicated drug class (n=18; 62%), with piperacillin-tazobactam allergy accounting for half of these (n=9; 50%). Reaction phenotypes included cutaneous (n=18; 62%), anaphylaxis (n=6; 21%), mixed cutaneous and angioedema (n=4; 14%), and one delayed reaction. Anaphylaxis was triggered by piperacillin–tazobactam (n=2), chlorhexidine, urokinase, rituximab, and amphotericin B.  Multiple drug allergic reactions were documented in three patients.  Food and environmental allergy observed in 8.4% and 3.5% of patients, respectively.

Drug allergy affected a substantial proportion of paediatric liver transplant recipients, with diverse reaction phenotypes including anaphylaxis, mainly post-transplant. Antibiotics were the most frequently implicated drug class, with piperacillin–tazobactam predominating, likely reflecting repeated exposure in the pre- and post-transplant setting. Careful allergy phenotyping and specialist assessment are important to support safe prescribing and individualised antimicrobial management in this complex population. Further research is planned to investigate additional risk factors in this patient group.