Ulcerative Colitis after Administration of Dupilumab, an Anti-interleukin-4 Receptor Subunit α Monoclonal Antibody.

We report the case of a 38-year-old woman who visited our hospital because of persistent bloody stool one month after starting treatment with dupilumab, an anti-interleukin-4 receptor subunit α monoclonal antibody, for bronchial asthma. Based on the lower gastrointestinal endoscopy findings, the patient was diagnosed with ulcerative colitis. Despite medication, the patient's bloody stool was not well controlled; however, the situation improved after discontinuation of dupilumab. Based on the patient's clinical course, drug-induced ulcerative colitis due to dupilumab was diagnosed. Careful monitoring of the symptoms associated with the development of enteritis is necessary after dupilumab administration.