Ulcerative colitis is one of 2 major types of inflammatory bowel disease — a condition which causes the bowel (colon) to become inflamed. The other type of inflammatory bowel disease is known as Crohn’s disease.

Inflammatory bowel disease is a totally different condition from irritable bowel syndrome (IBS). In IBS, the functioning of the bowel is affected but there is no inflammation.

Ulcerative colitis and Crohn’s disease are long-term, chronic (ongoing) conditions which can flare up, on and off, throughout life.

What are the symptoms?

Most commonly, the symptoms of ulcerative colitis include:

  • abdominal pain, which is often crampy;
  • a feeling of urgently needing to open the bowels;
  • blood, mucus or pus in the stool;
  • diarrhoea;
  • fatigue and tiredness;
  • weight loss; and
  • loss of appetite.

People with ulcerative colitis may also develop other symptoms unrelated to the bowel. These can include:

  • mouth ulcers;
  • skin problems;
  • joint pains;
  • eye problems; and
  • liver disease.

Sometimes, malabsorption of important nutrients can occur.

Many people with ulcerative colitis feel well most of the time and don’t have any symptoms. This means the disease is not ‘active’ at this time, or can be said to be in remission. When the disease flares up and causes symptoms, this is known as a relapse.

Most of the time a trigger for a relapse can’t be identified, although some people find that stress, infections, some medicines or certain foods can trigger symptoms. It should be remembered that none of these is the cause of the disease itself.

Depending on where the inflammation occurs in the large bowel, ulcerative colitis can also be called:

  • proctitis (involving the rectum only);
  • proctosigmoiditis, or distal colitis (involving the rectum and sigmoid colon); or
  • universal or pan-colitis, which means the entire colon is affected.

Doctors don’t know why some people’s disease spreads to involve their entire colon yet in others the disease is confined to one area of it.

What is the difference between ulcerative colitis and Crohn’s disease?

It can sometimes be difficult to distinguish between ulcerative colitis and Crohn’s disease, particularly in the early stages, because the symptoms are very similar.

The major difference between the 2 include the following.

  • In ulcerative colitis the inflammation affects only the inner lining of the bowel wall, whereas in Crohn’s disease the inflammation is of the full thickness of the bowel wall.
  • The distribution of inflammation geographically within the gastrointestinal tract: ulcerative colitis affects only the large bowel (colon and rectum) and Crohn’s disease can affect any part of the gastrointestinal tract from the mouth to the anus.
  • With Crohn’s disease there may be patches of healthy bowel next to patches of the diseased bowel. The inflammation of ulcerative colitis, on the other hand, is a continuous inflammation.

Who gets ulcerative colitis?

Ulcerative colitis affects people of all ages, but usually starts between the ages of 15 and 30 years. There is another (smaller) peak in the diagnosis of this disease between the ages of 50 and 70 years.

Although ulcerative colitis is uncommon in children, it can have more severe effects than in adults if it is not treated, such as delayed or stunted growth.

Having a close family member with ulcerative colitis puts you at increased risk of developing the condition.

What causes ulcerative colitis?

Unfortunately the cause is still unknown despite intensive research. Causative factors that have been suggested include:

  • genetic predisposition;
  • infectious agents (bacteria and viruses);
  • defects in the immune system; and
  • environmental factors.

Some doctors suggest a combination of some or all of these factors may be involved. Psychological stress and food allergies are not thought to play a role in development of the disease.


Ulcerative colitis is sometimes difficult to diagnose because its symptoms can be similar to other conditions such as bowel infections or irritable bowel syndrome. Most people with suspected ulcerative colitis will need a colonoscopy or sigmoidoscopy to confirm the diagnosis.

Colonoscopy and flexible sigmoidoscopy are endoscopic examinations, in which a thin, flexible tube with a light on it (an endoscope) is passed into the rectum to allow the doctor to view the lining of your bowel. You will be lightly sedated during the procedure. The doctor may take several small pieces of tissue from the lining of your bowel for examination under a microscope. This is called a biopsy.

Blood tests can reveal whether you have anaemia or any vitamin or mineral deficiencies. Blood tests can also confirm that there is inflammation in the body.

Testing of stool samples may also be recommended by your doctor to help make the diagnosis.

Last Reviewed: 19/11/2015



1. Gastroenterological Society of Australia (GESA); Digestive Health Foundation (DHF). Information about inflammatory bowel disease (IBD); Third Edition, 2013. http://www.gesa.org.au/consumer.asp?id=17 (accessed Oct 2015).
2. Ulcerative colitis (revised February 2011). In: eTG complete. Melbourne: Therapeutic Guidelines Limited; 2015 Jul. http://online.tg.org.au/complete/ (accessed Oct 2015).
3. National Institute of Diabetes and Digestive and Kidney Diseases. Ulcerative colitis (updated 3 Sep 2014). http://www.niddk.nih.gov/health-information/health-topics/digestive-diseases/ulcerative-colitis/Pages/facts.aspx (accessed Oct 2015).