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Complications - Ulcerative colitis

If you have ulcerative colitis, you could develop further problems.


People with ulcerative colitis are at an increased risk of developing osteoporosis, when the bones become weak and are more likely to fracture.

This is not directly caused by ulcerative colitis, but can develop as a side effect of the prolonged use of corticosteroid medication.

It can also be caused by the dietary changes someone with the condition may take, such as avoiding dairy products, if they believe it could be triggering their symptoms.

If you're thought to be at risk of osteoporosis, the health of your bones will be regularly monitored.

You may also be advised to take medication or supplements of vitamin D and calcium to strengthen your bones.

Find out more about treating osteoporosis

Poor growth and development

Ulcerative colitis, and some of the treatments for it, can affect growth and delay puberty.

Children and young people with ulcerative colitis should have their height and body weight measured regularly by healthcare professionals.

This should be checked against average measurements for their age.

These checks should be carried out every 3 to 12 months, depending on the person's age, the treatment they're having and the severity of their symptoms.

If there are problems with your child's growth or development, they may be referred to a paediatrician (a specialist in treating children and young people).

Primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC), where the bile ducts become progressively inflamed and damaged over time, is a rare complication of ulcerative colitis.

Bile ducts are small tubes used to transport bile (digestive juice) out of the liver and into the digestive system.

PSC does not usually cause symptoms until it's at an advanced stage.

Symptoms can include:

  • fatigue (extreme tiredness)
  • diarrhoea 
  • itchy skin
  • weight loss
  • chills
  • a high temperature (fever)
  • yellowing of the skin and the whites of the eyes (jaundice)

There's currently no specific treatment for PSC, although medications can be used to relieve some of the symptoms, such as itchy skin.

In more severe cases, a liver transplant may be required.

Toxic megacolon

Toxic megacolon is a rare and serious complication of severe ulcerative colitis where inflammation in the colon causes gas to become trapped, resulting in the colon becoming enlarged and swollen.

This is potentially very dangerous as it can cause the colon to rupture (split) and cause infection in the blood (septicaemia).

The symptoms of a toxic megacolon include:

  • tummy pain
  • a high temperature (fever)
  • a rapid heart rate

Toxic megacolon can be treated with fluids, antibiotics and steroids given directly into a vein (intravenously).

If medications do not improve the conditions quickly, surgical removal of the colon (a colectomy) may be needed.

Treating symptoms of ulcerative colitis before they become severe can help prevent toxic megacolon.

Bowel cancer

People who have ulcerative colitis have an increased risk of developing bowel cancer (cancer of the colon, rectum or bowel), especially if the condition is severe or involves most of the colon.

The longer you have ulcerative colitis, the greater the risk.

People with ulcerative colitis are often unaware they have bowel cancer as the initial symptoms of this type of cancer are similar.

These include:

  • blood in the stools
  • diarrhoea
  • abdominal pain

You'll usually have regular check-ups to look for signs of bowel cancer from about 10 years after your symptoms first develop.

Check-ups will involve examining your bowel with a colonoscope (a long, flexible tube containing a camera) that's inserted into your rectum – this is called a colonoscopy.

The frequency of the colonoscopy examinations will increase the longer you live with the condition, and will also depend on factors such as how severe your ulcerative colitis is and if you have a family history of bowel cancer.

This can vary between every 1 to 5 years.

To reduce the risk of bowel cancer, it's important to:

  • eat a healthy, balanced diet including plenty of fresh fruit and vegetables
  • take regular exercise
  • maintain a healthy weight
  • avoid alcohol and smoking

Taking aminosalicylates as prescribed can also help reduce your risk of bowel cancer.

Find out more about preventing bowel cancer

Page last reviewed: 23 January 2019
Next review due: 23 January 2022