Eosinophilia and gastrointestinal symptoms in Immunosuppression: a classic but overlooked diagnosis.

A 77-year-old man with idiopathic hypereosinophilic syndrome on corticosteroids presented with fever, diarrhea, and anemia. Initial investigations, including screening for enteric pathogens, were negative, and empirical antibiotics were initiated, with subsequent deterioration. Endoscopy revealed Strongyloides stercoralis in the duodenal wall. Treatment with ivermectin resulted in clinical and hematologic resolution. This case highlights the need to consider strongyloidiasis in the differential diagnosis of peripheral eosinophilia.