Ulcerative Colitis

Lifelong, intermittent inflammation and ulceration of the rectum and colon

  • Onset most common between the ages of 15 and 35
  • Sometimes runs in families; more common in white people and in certain other ethnic groups
  • More common in nonsmokers and ex-smokers
  • Gender is not a significant factor

Ulcerative colitis is a lifelong, intermittent inflammatory disorder that most commonly develops in young adults. The disorder causes ulceration of the rectum and the colon (the major part of the large intestine). It may either affect the rectum alone (see Proctitis) or extend from the rectum further up the colon. In some cases, the disorder involves the entire colon.

Ulcerative colitis affects about 1 in 1,000 people. It occurs most frequently in white people, particularly those of Jewish descent. Smoking may give some protection against the disease.

What is the cause?

The exact cause of ulcerative colitis is unknown. However, there is some evidence that genetic factors are involved, since about 1 in 10 people with ulcerative colitis has a close relative who has the disease. There may also be a family history of intestinal diseases, such as Crohn’s disease, and of allergic disorders, such as eczema.

Ulcerative colitis

This endoscopic view of a colon affected by ulcerative colitis shows extensive ulceration of the intestinal lining.

What are the symptoms?

The symptoms of ulcerative colitis are often intermittent, and there may be several months or years in which there are few or no symptoms. In a mild episode, symptoms often develop over a few days and may include the following:

  • Diarrhoea, sometimes with blood and mucus in the stool.

  • Abdominal cramps.

  • Tiredness.

  • Loss of appetite.

In a severe attack, the symptoms may begin suddenly, developing over just a few hours. Symptoms may include:

  • Severe bouts of diarrhoea, at least six times a day.

  • Passage of blood and mucus from the anus.

  • Pain and swelling in the abdomen.

  • Fever.

  • Weight loss.

People with ulcerative colitis often have other associated disorders. These include pain in the joints and in the spine (see Arthritis, and Ankylosing spondylitis), inflammation in the eye (see Uveitis), and the skin condition erythema nodosum.

Are there complications?

Rarely, a severe, sudden attack of ulcerative colitis may lead to toxic megacolon. In this condition, the inflamed colon becomes greatly distended. As a result, the wall of the colon can perforate, allowing intestinal contents containing bacteria to leak into the abdominal cavity. This leakage can cause peritonitis, a potentially fatal disorder.

People with ulcerative colitis are also at greater risk of developing colorectal cancer. The risk is increased further if the ulcerative colitis is extensive, severe, and of long duration.

How is it diagnosed?

If your symptoms are fairly mild, your doctor will probably ask you for a faecal sample, which will be tested to exclude the possibility of an infection. The definitive test for ulcerative colitis is direct examination of the colon with an endoscope. You may therefore have a colonoscopy, during which a small sample of tissue may be removed from the lining of the rectum or the colon for microscopic examination. You may also have blood tests to look for anaemia and to assess the extent of inflammation of the colon.

What is the treatment?

Ulcerative colitis is usually treated with drugs, but surgery may be necessary if you are experiencing frequent severe attacks or if complications develop.


Your doctor may prescribe the anti-inflammatory drug mesalazine (see Aminosalicylate drugs) to prevent attacks of ulcerative colitis or treat mild episodes. If the inflammation is confined to the rectum or the lower part of the colon, your doctor may prescribe topical aminosalicylate drugs (in the form of suppositories or enemas) for you to self-administer. If the ulcerative colitis affects more of the colon, you will be given the drugs to take orally. In some cases, your doctor may prescribe both topical and oral aminosalicylates.

If you have sudden, severe attacks of the disorder, your doctor will probably pre-scribe corticosteroids to be taken orally or as an enema. Long-term use of corticosteroids may cause various side effects, such as weight gain, a moon-shaped face, and thinning of the bones (see Osteoporosis). For this reason, the doctor will reduce the dose once your symptoms have started to subside and stop the treatment as soon as possible.

If these treatments are ineffective, your doctor may suggest immunomodulator drugs, such as azathioprine. These drugs reduce intestinal inflammation by suppressing the immune system. However, they may produce potentially serious side effects and regular monitoring is required during treatment.


Surgical treatment is usually necessary for people who experience persistent symptoms despite treatment with drugs. It may also be recommended for people who have a sudden, severe attack that does not respond to medical treatment and that may lead to toxic megacolon. In addition, surgery may be advisable for people with an increased risk of colorectal cancer. Surgery usually involves the removal of the diseased colon and rectum (see Colectomy) and creation of a stoma, which is an artificial opening in the abdominal wall through which the small intestine can expel faeces (see Colostomy). A newer procedure called a pouch operation is suitable for some people. In this procedure, part of the small intestine is used to create a pouch that connects the small intestine to the anus. This operation avoids the need for a stoma, but the pouch may become inflamed and the frequency of bowel movements often increases.

What is the prognosis?

Some people have only one attack of ulcerative colitis, but most have recurring episodes. About 1 in 5 people needs to have surgery. Colorectal cancer is the greatest long-term risk, and it eventually develops in about 1 in 6 people whose entire rectum and colon have been affected for 25 years or more. If you have long-standing, extensive ulcerative colitis but have not had surgery, you will need regular colonoscopy to detect early signs of colorectal cancer.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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