Case ReportsCOVID-19–Associated Eosinopenia in a Patient With Chronic Eosinophilia Due to Chronic StrongyloidiasisStylemans, Dimitri MD∗; Van Cauwelaert, Stefan MD†; D'Haenens, Alexander MD‡; Slabbynck, Hans MD§Author Information From the ∗Department of Pulmonology, University Hospital UZ Brussel, Brussels †Department of Pulmonology, ZNA Middelheim, Antwerp ‡Department of Pulmonology, University Hospital UZ Leuven, Leuven §Department of Pulmonology, ZNA Middelheim, Antwerp, Belgium. Correspondence to: Dimitri Stylemans, MD, Department of Pulmonology, University Hospital UZ Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium. E-mail: [email protected]. The authors have no funding or conflicts of interest to disclose. Infectious Diseases in Clinical Practice: September 2021 - Volume 29 - Issue 5 - p e305-e306 doi: 10.1097/IPC.0000000000000991 Buy Metrics Abstract Eosinopenia was frequently encountered in patients with coronavirus disease 2019 (COVID-19). We describe a case of a 59-year-old man who was treated with high-dose corticosteroids and anti-interleukin 1 receptor antagonist therapy because of severe acute respiratory distress syndrome due to a so-called cytokine storm in COVID-19. He had chronic eosinophilia for many years due to an unknown Strongyloides stercoralis infection, proven by serology and a positive polymerase chain reaction test on a stool sample. COVID-19 led to a complete resolution of eosinophilia, even before immunosuppressive treatment was started. Eosinophilia returned after recovery from COVID-19 and started to decline under treatment with ivermectin. Our case confirms previous reports of eosinopenia in COVID-19, as it appears even in patients with chronic eosinophilia. Presence of eosinophilia should prompt screening for strongyloidiasis in all patients eligible for immunosuppressive therapy because of the risk of Strongyloides hyperinfection syndrome, especially if this treatment is empirical. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.