What is left-sided (distal) colitis?

What is distal ulcerative colitis?

Left-sided (distal) colitis is a form of ulcerative colitis (UC) that begins at the rectum and extends up to the left colon (sigmoid colon and descending colon).

It is a life-long chronic condition which cannot currently be cured and is part of a group of conditions known as inflammatory bowel disease (IBD). UC causes inflammation of the gastrointestinal tract (gut).

In UC small ulcers develop on the colon’s lining which produce pus and mucus. This can cause abdominal discomfort and frequent emptying of the colon (diarrhoea).

Approximately 30% of people with UC are diagnosed with left-sided colitis.

What are the symptoms of left-sided colitis?

Typical symptoms include:

  • Loss of appetite
  • Weight loss
  • Diarrhoea with blood and mucus
  • Urgency to empty bowels
  • Tenesmus - feeling the need to pass stools despite bowel being empty
  • Severe pain on left side of abdomen


What are the treatments for left-sided colitis?

Treatments currently include medication and surgery. Some people have severely inflamed or damaged parts of their colon surgically removed. This can reduce or eliminate the symptoms of left-sided colitis, however it does not get rid of the disease and there is a risk that it will return to another area of the colon in the future.

Some people also make adjustments to their diet and lifestyle to support their medical treatment - such as exercise, improving quality of sleep, reducing stress.

What complications can occur with left-sided colitis?

  • Toxic megacolon: The colon can acutely dilate when the inflammation becomes very severe - known as toxic megacolon. Symptoms include fever, abdominal pain and distention, dehydration and malnutrition. With toxic megacolon there is a risk of colonic rupture
  • Anaemia: Blood loss from the inflamed intestines can lead to anaemia which can be treated with iron supplements or sometimes blood transfusions
  • Cancer: The risk of bowel cancer is increased against the general population but is not as high as in those with chronic pan-ulcerative colitis

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