Severe hypereosinophilia secondary to intestinal whipworm infection with negative stool tests: a case report

Severe hypereosinophilia is commonly associated with hematologic disorders, whereas parasitic infections are often underrecognized, particularly in non-endemic settings. The diagnosis can be further complicated when routine stool examinations are negative.

A 24-year-old man presented with a 2-month history of chronic diarrhea and marked hypereosinophilia (11.56 × 10⁹/L). Initial investigations, including repeated stool examinations and colonoscopy, failed to identify an underlying cause, leading to diagnostic uncertainty. The patient was initially treated for a nonspecific gastrointestinal disorder, with only transient symptomatic relief. Upon readmission, a repeat colonoscopy revealed two Trichuris trichiura worms in the cecum and ascending colon, which were successfully removed endoscopically. Histopathological examination demonstrated prominent eosinophilic infiltration. Following a short course of albendazole (400 mg once daily for 3 days), the patient's symptoms resolved completely, and eosinophil counts rapidly normalized, with no residual gastrointestinal symptoms during follow-up.

Clinicians should maintain a high index of suspicion for parasitic infections in patients with unexplained hypereosinophilia and gastrointestinal symptoms. Repeated evaluations, including colonoscopy, may be essential for establishing the diagnosis and guiding timely treatment.