Enterobius vermicularis infection associated with positive faecal occult blood testing and eosinophilia

A 60-year-old asymptomatic man attended following positive faecal occult blood testing in the UK bowel cancer screening programme. He was a regular carer for young grandchildren. Recent tests showed an elevated eosinophil count (0·82 × 109 cells per L [range 0·04–0·4]). Colonoscopy patchy erythema and erosions with multiple Enterobius vermicularis (threadworm or pinworm) caecum (figure, A). Histopathological examination B) surface epithelial erosion, attenuation, regenerative changes E parasite C). Crypt architecture maintained, but there eosinophil-rich inflammatory cell infiltrate within lamina propria D).