COVID-19-Associated Eosinopenia in a Patient With Chronic Eosinophilia Due to Chronic Strongyloidiasis

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.