PT - JOURNAL ARTICLE AU - Toshikazu Ozeki AU - Yoshiro Fujita TI - Asymptomatic colitis induced by low-dose methotrexate AID - 10.1136/bcr-2016-217771 DP - 2016 Nov 25 TA - BMJ Case Reports PG - bcr2016217771 VI - 2016 4099 - http://casereports.bmj.com/content/2016/bcr-2016-217771.short 4100 - http://casereports.bmj.com/content/2016/bcr-2016-217771.full AB - A woman aged 77 years with a history of rheumatoid arthritis (RA) presented with inflammatory colitis confined to her rectum, which was incidentally found by a screening colonoscopy. Histopathological examination of colonic biopsies showed non-specific inflammatory infiltrates of lymphocytes, the cause of which was unknown. She had been diagnosed with RA 5 years before, and she was receiving methotrexate 6 mg weekly, to which tocilizumab had been added 4 years earlier, which achieved stable control of her disease. She had no gastrointestinal symptoms or other health problems. Tocilizumab-induced colitis was considered likely, and the drug was discontinued. Metronidazole was also prescribed because of possible Clostridium difficile-associated colitis. 3 months later, a repeat colonoscopy showed no improvement of the colitis. The methotrexate was also discontinued, and folinic acid was prescribed daily for 2 weeks, leading to complete resolution of the colitis observed at repeat colonoscopy.