Ulcerative colitis

What is ulcerative colitis?

Ulcerative colitis is a long-term, chronic condition affecting the large intestine (colon). It affects the rectum (the part of the large bowel that lies just inside the anus) and the colon. The colon becomes inflamed and, if this inflammation becomes severe, the lining of the colon is breached and ulcers may form.


The amount of inflammation in ulcerative colitis is very variable, and many people never develop ulcers, because their degree of inflammation is not that advanced. In mild cases, the colon can look almost normal, but when the inflammation is widespread, the bowel can look very diseased and can contain ulcers.

Who gets ulcerative colitis?

Ulcerative colitis is an uncommon condition. It can develop at any age, but usually starts between the ages of 15 and 30. Ulcerative colitis affects men and women equally. It is more common in white people of European descent – especially those descended from Ashkenazi Jewish communities – and black people. The condition is much rarer in Asian people.

What is inflammatory bowel disease?

Ulcerative colitis is one of two conditions known as ‘inflammatory bowel disease’, the other being Crohn’s disease.


Both these conditions can cause inflammation of the colon and rectum, with similar symptoms and treatments. The main differences are that the inflammation of ulcerative colitis is usually found just in the inner lining of the gut, while in Crohn’s disease the inflammation can spread through the whole wall of the gut. In addition, ulcerative colitis only affects the colon and rectum, while Crohn’s disease can affect any part of the gut.


Inflammatory bowel disease is sometimes shortened to IBD. This is not the same as IBS, which is short for irritable bowel syndrome, and which is a very different condition.

What causes ulcerative colitis?

The exact cause is unknown. Most researchers think that it is caused by a combination of factors. These include:


Genetics: Inherited genes may increase the risk of developing ulcerative colitis. The fact that ulcerative colitis is more common in some ethnic groups also suggests that genetic factors play an important role.


Immune system: Ulcerative colitis is called an autoimmune condition. This means the immune system – the body’s natural defence against infection and illness – goes wrong in some way and attacks healthy tissue. One theory is that the immune system mistakes the harmless bacteria – the ‘friendly bacteria’ inside the colon that help to digest food – as a threat and attacks the tissues of the colon, causing it to become inflamed.


Environmental factors:Ulcerative colitis is most common in countries with a modern western lifestyle, such as the UK. This suggests that the environment has a part to play, and various factors have been suggested. These include air pollution; diet (Asian people, who tend to eat a diet lower in carbohydrates and fats, are less affected by ulcerative colitis); and hygiene (the result of children being brought up in increasingly germ-free environments).

What are the symptoms?

The symptoms vary, and range from mild to severe. It depends on how much of your colon is affected and the level of inflammation. Symptoms are often worse first thing in the morning. Symptoms can flare up and then disappear, known as remission, for months or even years. This may be followed by periods when the symptoms are particularly troublesome, known as flare-ups.


Common symptoms include one or more of the following:

  • diarrhoea, with or without blood and mucus
  • abdominal pain
  • a frequent need to go to the toilet
  • weight loss.

Other symptoms include:

  • tiredness (fatigue)
  • loss of appetite
  • weight loss
  • anaemia (shortness of breath, irregular heartbeat, tiredness and pale skin)
  • high temperature (fever) of 38°C (100°F) or above
  • dehydration
  • a constant desire to empty the bowels
  • bloating and gas
  • heartburn and reflux.
How is ulcerative colitis diagnosed?

The starting point during an initial assessment is for your GP to ask about the pattern of symptoms, your general health and medical history,and whether there is a family history of ulcerative colitis.An examination will look for signs of inflammation, such as tenderness in the abdomen, and paleness that might be caused by anaemia.If your doctor suspects that the symptoms might point to ulcerative colitis, a referral will be made to a specialist for diagnostic tests.


Tests to diagnose ulcerative colitis may include one or more of the following:

  • blood test, to check for inflammation, anaemia and protein levels
  • stool sample, which is checked for infection
  • X-rays, to help assess the extent of the condition
  • sigmoidoscopy, to examine the extent of inflammation in the rectum and lower part of the colon
  • colonoscopy, to examine the inside of the entire colon.


Once the diagnosis is confirmed, you may be referred to a doctor who specialises in conditions of the digestive system (gastroenterologist) so that a treatment plan can be drawn up. The specialist will judge the severity of your condition by the following factors:

  • how many times you are passing stools
  • whether those stools are bloody
  • whether you also have more wide-ranging symptoms such as fever, rapid heartbeat and anaemia
  • how much control you have over your bladder
  • your general well-being.
What treatments are available?

There is currently no cure for ulcerative colitis. However, medication can improve symptoms and surgery can also help in many cases.

Is there a link with bowel cancer?

People with ulcerative colitis have an increased risk of developing bowel cancer and should be monitored regularly, especially if the condition is severe or extensive.


The longer you have ulcerative colitis, the greater the risk is:

  • after 10 years the risk of developing bowel cancer is 1 in 50
  • after 20 years the risk of developing bowel cancer is 1 in 12
  • after 30 years the risk of developing bowel cancer is 1 in 6.


While ulcerative colitis and bowel cancer are two very different conditions, it is important to note that many of the symptoms are the same for both. People with ulcerative colitis are often unaware that they have bowel cancer as the initial symptoms are similar to ulcerative colitis, such as blood in your poo, diarrhoea and abdominal pain. Because of this, you will probably be advised to have a colonoscopy every few years to check that no cancer has developed.

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