Exacerbation of inflammatory bowel disease with isotretinoin

A 27-year-old female medical student experienced an episode of intermittent bloody diarrhoea for 6 weeks. She had no prior illnesses, no family history of note and had not undergone any recent travel. Routine blood and stool tests by her GP were normal. A colonoscopy showed patchy moderately active colitis and biopsies revealed patchy mild to moderate chronic active inflammation with cryptitis and no granulomas. The features were in keeping with, but not diagnostic of, ulcerative colitis. Since symptoms had completely abated, the patient decided against starting treatment. Six months later, she started a 16-week course of isotretinoin 40 mg daily for acne vulgaris. During week 14 of the treatment she developed bloody diarrhoea three to four times a day, which was treated with enteric coated mesalasine by her GP. At the end of the isotretinoin course her symptoms worsened – her stool frequency increased to 15 bloody motions daily with a CRP of 46 mg/L. She was treated with intravenous hydrocortisone and high-dose mesalazine. However, after 3 days the stool frequency and CRP had not fallen. A flexible sigmoidoscopy revealed severely active colitis with multiple superficial ulcers. Intravenous ciclosporin produced no response and a subtotal colectomy and ileostomy was performed. Histology showed severe acute-on-chronic ulcerative colitis with no viral inclusions or granulomas. Discussion