Objective: To characterize changes in eosinophil counts over time, and to draw comparisons across four gestational age groups with respect to the incidence of, and clinical conditions associated with eosinophilia over the first months of life in a single neonatal intensive care unit (NICU).
Study design: Weekly complete blood counts (CBCs) were collected from all NICU patients. Eosinophilia was classified as mild, moderate, or severe. Changes in eosinophil counts were examined over time, the incidence of eosinophilia was determined by gestational age group, and clinical correlations sought.
Results: Eosinophil data from 1652 CBCs were analyzed from 332 infants. Eosinophilia occurred in 148 infants (45%) during their hospitalization. The prevalence, severity, and timing of eosinophilia varied by gestational age, infection, and red blood cell transfusions.
Conclusions: The incidence and severity of eosinophilia increased with immaturity, and was temporally associated with infection, necrotizing enterocolitis, and packed red blood cell transfusion.