ulcerative colitis (UC)

Last edited 07/2019 and last reviewed 01/2023

Ulcerative colitis is a chronic inflammatory disease in which a part or the whole of the mucosa of the large bowel becomes diffusely inflamed and may ulcerate, as a result of which the patient suffers from diarrhoea which may be bloody.

  • usually starts in the rectum and extends proximally in a symmetrical, circumferential, and uninterrupted pattern (1,2)  
  • may affect parts of the colon, or its entire mucosal surface
  • characterised by exacerbations and remissions (1).

The cause of ulcerative colitis is unknown but genetic, immunological, dietary, and psychological factors have all been implicated.

The highest incidence of this disease is in adulthood, although it may occur in childhood

According to the Montreal classification, the extent of ulcerative colitis can be classified as:

  • ulcerative proctitis – inflammation is limited to the rectum (proximal extent of inflammation is distal to the rectosigmoid junction)
  • left sided UC (distal UC) – inflammation limited to a proportion of the colorectum up to the splenic flexure
  • extensive UC (pancolitis) - involvement extends beyond the splenic flexure (3)

Notes (4):

  • ulcerative colitis is the most common type of inflammatory bowel disease

    • around 146,000 people in the UK with a diagnosis of ulcerative colitis (Crohn's & Colitis UK)
    • cause of ulcerative colitis is unknown
    • can develop at any age, but peak incidence is between the ages of 15 and 25 years, with a second, smaller peak between 55 and 65 years (although this second peak has not been universally demonstrated)

  • ulcerative colitis degree of large bowel involvement:
    • usually affects the rectum, and a variable extent of the colon proximal to the rectum - the inflammation is continuous in extent
    • inflammation of the rectum is referred to as proctitis, and inflammation of the rectum and sigmoid as proctosigmoiditis
    • left-sided colitis refers to disease involving the colon distal to the splenic flexure
    • extensive colitis affects the colon proximal to the splenic flexure, and includes pan-colitis, where the whole colon is involved

  • symptoms of active disease or relapse include bloody diarrhoea, an urgent need to defecate and abdominal pain

  • ulcerative colitis is a lifelong disease that is associated with significant morbidiy
    • can also affect a person's social and psychological wellbeing, particularly if poorly controlled
    • typically, it has a relapsing-remitting pattern

  • current medical approaches focus on treating active disease to address symptoms, to improve quality of life, and thereafter to maintain remission
    • long-term benefits of achieving mucosal healing remain unclear
    • treatment chosen for active disease is likely to depend on clinical severity, extent of disease and the person's preference, and may include the use of aminosalicylates, corticosteroids or biological drugs
      • these drugs can be oral or topical (into the rectum), and corticosteroids may be administered intravenously in people with acute severe disease

  • surgery
    • may be considered as emergency treatment for severe ulcerative colitis that does not respond to drug treatment
    • people may also choose to have elective surgery for unresponsive or frequently relapsing disease that is affecting their quality of life