RESUMEN
BACKGROUND: Joint, skin, oral cavity, and eye lesions are the most common extraintestinal manifestations of ulcerative colitis that can occur before or after its onset. The cases of ulcerative colitis with dermatomyositis (DM) are rare. In this study, we report a rare case of ulcerative colitis with DM that was effectively treated with infliximab. CASE SUMMARY: The patient was a 57-year-old female with a 2-year history of DM. The patient was admitted to hospital with abdominal pain, diarrhea, and blood in stool lasting for more than 2 mo. Colonoscopy revealed multiple erosions and ulcers in the entire colon and rectum. Pathological sections showed chronic inflammatory cell infiltration, especially neutrophil infiltration, in the colonic mucosa; therefore, the patient was diagnosed with ulcerative colitis. Preparations of 5-aminosalicylic acid was added to her treatment based on the original treatment for DM, but its effect was unsatisfactory. The patient's discomfort was relieved after infliximab treatment. CONCLUSION: Infliximab can improve DM in the treatment of ulcerative colitis. Specialists need to raise awareness about patients with inflammatory bowel disease who have rare extraintestinal manifestations.