Ulcerative Colitis Exacerbated by Strongyloidiasis

We present the case of a 64-year-old female who was diagnosed with ulcerative colitis (UC) in clinical remission with oral mesalazine in a subtropical island of Japan. However, she presented hematochezia and fever (38.6 ??C) four months later. Laboratory examination showed white blood cells of 9,900/ ??l, hemoglobin of 12.5 g/dl and CRP of 6.1 mg/dl (reference range: < 0.26 mg/dl). Sigmoidoscopy revealed Mayo score grade 3 inflammation consistent with exacerbation of UC (Fig. 1A). Stool microscopy revealed Strongyloides stercoralis (S. stercoralis) larvae (Fig. 1B), and she started with ivermectin, which completely treated a potentially lethal S. stercoralis hyperinfection. After eradication, she started on prednisolone, leading to clinical and endoscopic remission of UC flare-up.