A Retrospective Review of 193 Cases of Severe Eosinophilia in the Northeast United States.

BACKGROUND

This retrospective review evaluated the causes of severe eosinophilia (≥5000 eosinophils/L). Higher eosinophilia levels are more likely to cause tissue damage and may reflect disease severity.

METHODS

We reviewed 193 cases of patients seen at Beth Israel Deaconess Medical Center in Boston, Massachusetts, and at the University of Vermont Medical Center in Burlington, Vermont, between January 2015 to May 2020 who had a peak absolute eosinophil count of at least 5000/μL.

RESULTS

Thirty-nine percent of cases were attributable to a hematologic or oncologic cause. These cases had the highest mean peak absolute eosinophil count at 11,698/μL. Twenty percent of cases were secondary to drug reactions, of which 90% took place in an inpatient setting. Three percent of cases were from helminthic infection, the majority of which were in returning travelers.

CONCLUSIONS

In our region of study, hematologic and oncologic cases are important causes of severe eosinophilia, drug reactions are a common etiology in the inpatient setting, and infections are a rare cause.