What is Ulcerative Colitis?

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Ulcerative colitis is a chronic inflammatory disease that affects only the innermost lining of the colon. The severity and extension of inflammation varies in each patient.

It can affect the following areas:

  • Proctitis: affects just the rectum
  • Proctosigmoiditis: affects the rectum and sigmoid
  • Left-sided or distal ulcerative colitis: affects just the left colon (up to the splenic flexure)
  • Pancolitis: those cases which extend beyond the splenic flexure

Most frequent symptoms of Ulcerative Colitis

Person standing with diarrhoea cramps


Blood in the stool

Stools containing mucus and/or blood (rectal bleeding)

Numerous and small stools

A high frequency of small volume stools

Person going to a toilet with frequent urge to evacuate

Frequent and urgent need to defecate

Abdominal pain at night due to nocturnal bowel movements

Nocturnal stools

Standing person holding hands to abdomen because of cramps


Thermometer with a danger signal indicating fever

Fever, abdominal pain and poor overall health (due to fatigue, loss of appetite and weight loss) are all indicative of the condition’s severity.

Substantiated information by:

Ingrid Ordas Jimenez
Marta Gallego Barrero

Published: 20 February 2018
Updated: 4 September 2020

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