RÉSUMÉ
Abstract Introduction: Although it is an essential component of the treatment of acute lymphoid leukemia in children, asparaginase causes adverse reactions that sometimes make it impossible to use it fully. Hypersensitivity reactions are the most frequent and may lead to early discontinuation of treatment. The present study aimed to investigate suspicions of adverse reactions during the infusion of asparaginase in a pediatric cohort. Methods: A retrospective observational study was carried out at a university pediatric institute in the state of Rio de Janeiro. Information regarding clinical features and characteristics of adverse reactions was collected from hospital medical records. Suspicions of adverse reactions were classified regarding causality and severity. Results: Seventy-three suspicions of adverse reactions were recorded during asparaginase infusion in 72 children in the study period. Allergic hypersensitivity reactions were suspected in 60.5% of the cases. Of these, 25% of the reactions occurred during induction and 61.1% in concomitant use with vincristine, findings that diverge from other studies. High-risk classification and younger age were considered risk factors for these reactions. A total of 72.4% of the reactions were classified as grade 1 or 2, which suggest that not all are related to antibody formation; this highlights the importance of differential diagnosis with other reactions, such as non-allergic hypersensitivity and hyperammonemia. Conclusion: The implementation of the differential diagnosis of reactions related to infusion of asparaginase with ammonia dosage and classification of the grade of reactions is crucial to facilitate the identification and proper management of each type of reaction.