Pediatric Anal Pruritus and Misdiagnosis: Dipylidium caninum in a Spanish Child with a Review of Reported Human Cases

Intestinal helminth infections in children remain a significant public health problem worldwide. Among these, those caused by cestodes can be misdiagnosed, as occurs with dipylidiasis, a zoonosis caused by Dipylidium caninum. Although common in dogs and cats, human infection is rare and may be misdiagnosed as Enterobius vermicularis due to overlapping symptoms. We present the case of a 3-year-old Spanish boy with intense anal itching, treated twice with mebendazole for presumed pinworm infection without improvement. Persistent symptoms, anorexia, and weight loss prompted a parasitological examination. Microscopic examination of whitish structures in the feces revealed gravid proglottids with bilateral genital pores and egg packets containing hexacanth embryos, confirming D. caninum infection. Epidemiological investigation suggested exposure to a relative's dog as the probable source. Treatment with paromomycin sulfate resulted in complete cure. This case highlights the importance of recognizing the characteristic morphology of D. caninum to avoid misdiagnosis and inappropriate therapy.