Infliximab-Induced Autoimmune Phenomenon in an Adolescent With Ulcerative Colitis: Drug-Induced Lupus vs Inflammatory Myositis.

We present the case of a 15-year-old female with ulcerative colitis who developed an asymptomatic rise in creatine kinase and transaminases while on infliximab therapy. Additional rheumatologic workup revealed high-titer anti-nuclear antibody and positive anti-histone antibody, with the absence of myositis-specific autoantibodies. A drug-induced autoimmune phenomenon was suspected, with the patient lacking any muscle weakness or lupus features. The patient was subsequently switched to ustekinumab, which resulted in complete normalization of her labs while maintaining remission of her ulcerative colitis.