About One Third of Patients Who Receive Long-Term Antibiotics Will Develop Eosinophilia

In Western countries, medications are the most common cause of eosinophilia. Typically, drug-induced eosinophilia is self-limiting and asymptomatic; however, it occasionally is associated with severe hypersensitivity reactions, including organ-specific reactions (e.g., immune-mediated kidney, liver, and lung injury) and severe cutaneous reactions, such as drug rash with eosinophilia and systemic symptoms (DRESS). In a Boston study, a cohort of 824 adults who were discharged from a tertiary hospital with at least 2 weeks of home intravenous antibiotics (median duration, 41 days) was analyzed to determine the incidence of eosinophilia and hypersensitivity reactions.

Weekly testing showed that 25% of patients developed eosinophilia (absolute eo…