Eosinophilic colitis recrudescence two decades after initial pentastomiasis.

Visceral pentastomiasis is a rare parasitic infection that can mimic gastrointestinal inflammatory disorders. We report a Thai female farmer in her early 60s who presented with recurrent eosinophilic colitis two decades after an incidentally diagnosed pulmonary pentastomiasis. The clinical course was characterised by chronic watery diarrhoea without weight loss, peripheral eosinophilia (11%) and colonoscopy revealing multiple submucosal polypoid lesions throughout the colon. Radiological imaging showed numerous crescent-shaped calcifications, consistent with longstanding quiescent pentastomiasis. Histopathology showed dense eosinophilic infiltration of the lamina propria without identifiable organisms, suggesting a possible recrudescent inflammatory response associated with residual parasite material rather than active infection. This case highlights the potential for extremely long latency periods and late recrudescence, presenting as eosinophilic colitis, underscoring the importance of considering rare parasitic aetiologies in patients with unexplained eosinophilic gastrointestinal disease, even in the absence of recent exposure.