Patient information from BMJ

Ulcerative colitis: what is it?

Last published:Aug 05, 2021

If you have ulcerative colitis your bowel becomes inflamed (swollen). This can cause unpleasant symptoms including pain and diarrhoea. But treatments can help control the condition.

What is ulcerative colitis?

Ulcerative colitis is a condition that can cause inflammation of the bowel. It is a long-term condition that can vary in its severity. A similar condition that you may have heard of is called Crohn’s disease. These conditions are sometimes grouped together under the name inflammatory bowel disease.

As well as swelling, ulcerative colitis can cause ulcers to form in the swollen part of the bowel. These can sometimes bleed or leak pus.

We don’t know for certain what causes the condition. But ulcerative colitis is probably what’s called an autoimmune condition. This means that the body’s immune system, which protects us against infection, goes wrong and starts to attack part of the body.

In the case of ulcerative colitis, it’s thought that the immune system attacks bacteria in your gut, even though these bacteria aren’t doing you any harm and may even be useful in helping you to digest food.

The cause of ulcerative colitis may also be partly genetic. This means that it might be more likely to happen to people who have family members who have inflammatory bowel disease.

What are the symptoms?

The most common symptoms of ulcerative colitis are:

• diarrhoea that often contains blood

• bleeding from the rectum

• abdominal (tummy) pain.

Other symptoms that are less common include:

• pain in your joints (arthritis)

• fever

• weight loss

• constipation, which can alternate with diarrhoea.

If your doctor thinks that you might have ulcerative colitis he or she will suggest one or more tests that can help with a clear diagnosis. These might include:

• a stool test. A sample of your stool (faeces or ‘poo’) is tested for the presence of some substances. For example, if you have white blood cells or certain proteins in your stool, this suggests that you might have ulcerative colitis

• blood tests

• a colonoscopy. A tiny camera is inserted into the rectum using a thin tube. This can show if you have ulcers and swelling in the bowel. If only the lower part of the bowel is looked at, it’s called a sigmoidoscopy

• a biopsy. This means that a sample of tissue is taken from the lining of the bowel for testing. This will be done at the same time as a colonoscopy or sigmoidoscopy.

What to expect in the future?

Ulcerative colitis is very rarely life threatening, but it can be unpleasant, and if your symptoms are severe it can have a big impact on your life. Getting treatment to control the condition is important.

Having ulcerative colitis slightly increases your chance of getting colon cancer. So you will need to have a colonoscopy every one to five years. How often you need them will depend on how severe your ulcerative colitis is.

If you need to take medications called corticosteroids regularly to control your symptoms, you have an increased chance of osteoporosis. This means that your bones are weaker than normal, and you may be more likely to get fractures.

Your doctor should discuss this with you, and how best to avoid fractures. He or she might suggest that you have regular tests to check if your bones are affected.

Your doctor should also warn you about medicines that can make your condition worse, such as non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen.

There has been much discussion about how your diet might affect ulcerative colitis, but there isn’t much evidence about it. If you know that certain foods cause you to have symptoms, then you may want to stop eating them. But it is important to eat a healthy diet and make sure you are getting the nutrition you need.

Other things that will help keep you healthy include not smoking, not drinking too much alcohol, and taking plenty of exercise.

Your doctor may also advise you to take vitamin D and calcium supplements. But you should only take supplements of any kind after discussing them with your doctor, as some of them can interact with your medications.