Abstract
This work presents the case of a pediatric patient with very severe aplastic anemia (VSAA) who developed severe hypersensitivity reactions sequentially to a carbapenem antibiotic and subsequently to intravenous levofloxacin during an episode of severe neutropenia with fever. This case illustrates that serious drug hypersensitivity reactions can occur even in the context of profound immunosuppression. In managing this complex scenario, the Naranjo Algorithm was utilized to identify the culprit medications. When adjusting the anti-infective regimen, we carefully balanced the benefits and risks, ultimately selecting appropriate alternative antimicrobial agents. Furthermore, the patient tolerated a switch from intravenous to oral levofloxacin without further adverse reactions, leading to a successful discharge. This case highlights the need for heightened vigilance among clinicians and pharmacists regarding the potential for severe drug allergies in immunocompromised, critically ill patients. This case also aims to share practical experience, hoping to provide a reference for the challenging decision-making process of anti-infective therapy in this vulnerable population.