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Crohn’s disease

Key points

  • Crohn's disease can cause inflammation in any part of your digestive system from your mouth to your anus.
  • There isn't a cure for Crohn's disease but there are treatments to help ease your symptoms and prevent complications.
  • When your condition is in remission, you may find Crohn's disease has little impact on your day-to-day life. However, when you get a flare-up, your symptoms can make life more difficult.

Crohn's disease is a bowel disease that causes inflammation and ulcers in your digestive system. It can affect any part of your digestive tract from your mouth to your anus.

About Crohn's disease

Around 115,000 people in the UK have Crohn's disease.

Crohn's disease affects the wall of your bowel. It can affect any area from your mouth down through your stomach and bowel to your anus. However, it most commonly causes inflammation in the final part of your small bowel or the first part of your large bowel (colon). Crohn’s disease can affect more than one area of your bowel and leave areas in between completely unaffected.

Crohn's disease is a chronic illness. This means that it can last for a long time, sometimes for the rest of your life. The term chronic refers to how long you have the illness, not to how serious it is. However, it's usually a ‘relapsing and remitting’ condition. This means that your symptoms can disappear and then flare up again from time to time.

Crohn’s disease usually develops in teenagers and young adults, but you can get it at any age. It’s more common in women than men.

Illustration of the areas of the bowel commonly affected by Crohn's disease

Symptoms of Crohn's disease

Symptoms of Crohn's disease range from mild to severe. They can also settle down in one part of your bowel and then flare up in another. There may be long periods of time when you have few or no symptoms at all.

Symptoms of Crohn's disease include:

  • diarrhoea – sometimes with blood or mucus
  • pain in your abdomen (tummy), which can be severe
  • weight loss
  • a fever
  • tiredness

Crohn’s disease can also cause other problems, such as:

  • mouth ulcers
  • a rash on your skin
  • red and sore eyes
  • pain and swelling in your joints

If you have any of these symptoms, see your GP.

Complications of Crohn's disease

If you have severe inflammation of your bowel, you may develop complications.

Complications of Crohn’s disease include the following.

  • A fissure. This is a tear in the wall of your anus which can hurt and bleed when you go to the toilet.
  • A narrowing (stricture) in your bowel. This develops when scar tissue builds up after inflammation and it can partially or completely block your bowel. This can cause pain, vomiting and swelling in your abdomen.
  • An abscess (collection of pus). If the inflammation from Crohn’s disease affects the full thickness of your bowel wall, it's possible for a hole to develop. If this happens, the contents of your bowel can leak through it and cause an abscess. The abscess may then spread either through to your skin or into a nearby part of your body. This can cause a fistula.
  • A fistula. This is an abnormal connection between a hole in your bowel and the surrounding tissues. A fistula can develop between two parts of your bowel, or between your bowel and other parts of your body. This may be your bladder, vagina (in women) or skin.
  • Malnutrition and anaemia. Damage to your bowel can affect how well your body is able to absorb vitamins and minerals from your food.
  • Bowel cancer. Crohn's disease increases your risk of developing bowel cancer. See our frequently asked questions for more information.

Causes of Crohn's disease

The exact reasons why you may develop Crohn's disease aren't fully understood at present. However, your family history may play a role and increase your risk of getting it. Up to four in 10 people who have Crohn’s disease have a close relative who also has the condition. It’s thought that an abnormal immune reaction to certain bacteria or viruses in your bowel may cause the condition if you’re at increased risk.

You may also be more likely to develop Crohn’s disease if you:

  • smoke
  • have a diet that’s high in fat or sugar

Diagnosis of Crohn's disease

Your GP will ask about your symptoms and examine you. He or she will also ask you about your medical history.

Your GP may ask for a sample of your faeces to check for a bacterial infection. He or she will take a blood test to look for anaemia and signs of inflammation.

Your GP may refer you to a gastroenterologist (a doctor who specialises in identifying and treating conditions that affect the digestive system) for more tests. These may include the following.

  • A colonoscopy. Your doctor will insert a narrow, flexible, tube-like telescopic camera, called an endoscope, through your rectum (back passage) and into your bowel. This will enable your doctor to look inside your bowel and take samples of tissue for testing in a laboratory.
  • A capsule endoscopy. In this test, you will swallow a pill that transmits pictures as it passes through your bowel.
  • CT scan or MRI scan. These will produce images of the inside of your abdomen and are particularly useful to look for an abscess.
  • A white blood cell scan. This test looks for areas of inflammation in your bowel. You will need to give a blood sample. The white blood cells in this will be separated out and combined with a radioactive ‘tracer’ chemical that attaches to them. These will then be injected back into your body and a scanner will show where they (and the inflammation) are.
  • A barium meal or a barium enema X-ray. If you have a barium meal, you will be asked to drink fluid containing barium (a substance that shows up on X-ray images). A barium enema involves placing a fluid containing barium into your lower bowel through your rectum. X-rays of your abdomen will then show the inside of your bowel more clearly and can show if you have a fistula.

Treatment of Crohn's disease

There isn't a cure for Crohn's disease but there are treatments to help ease your symptoms and prevent complications. The treatment you have will depend on how severe your condition is. If your condition is mild, you may not need any treatment.


It's important to eat a healthy, balanced diet if you have Crohn’s disease. You may find that certain foods, such as those high in fibre, can make your symptoms worse. If this happens, it might help to remove these foods from your diet while you have symptoms. However, get some advice from a dietitian first. For more information, see our frequently asked questions.

During a flare-up, a liquid diet made up of simple forms of protein, carbohydrates and fats may help to ease your symptoms. These diets are called elemental or polymeric diets. You will need to follow them for three to six weeks. Because they are easier to digest they help rest your bowel, improve your nourishment and ease inflammation.


Medicines can help to prevent a flare-up or ease your symptoms of Crohn’s disease. You may need to go into hospital for treatment if you have severe symptoms during a flare-up.

The main treatments are listed below. You may need to have just one, or a combination of these.

  • Aminosalicylate (eg balsalazide, mesalazine or olsalazine). These can ease inflammation and reduce the chance of a flare-up (you take them all the time to help prevent this). If you do have a flare-up, your doctor may increase the dose to try to control your symptoms, or prescribe other treatments to reduce inflammation.
  • Corticosteroids (such as prednisolone, hydrocortisone and beclometasone). These are very effective but are usually only used for a short time during a flare-up. This is because they can cause side-effects such as diabetes, infections, cataracts, acne and osteoporosis. Immunosuppressants (such as azathioprine, mercaptopurine, ciclosporin and methotrexate) suppress your immune system and reduce inflammation but they may also increase your risk of infection.
  • Antibiotics (such as metronidazole or ciprofloxacin). These will reduce your risk of infection.
  • Biological therapies (such as infliximab or adalimumab). Your doctor will usually only prescribe you these if your symptoms are severe and other treatments haven't worked for you.

If you need pain relief, you can take over-the-counter painkillers, such as paracetamol. Don't take non-steroidal anti-inflammatory medicines (NSAIDs), such as ibuprofen or aspirin. These can cause a flare-up of Crohn's disease. Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your pharmacist or your doctor for advice.


Medicines will usually control your symptoms. However, if you have tried a number of different medicines and they haven't worked, your doctor may suggest surgery. You might also need surgery if you have complications of Crohn's disease, such as an abscess or fistula.

You may have an operation to remove a severely inflamed part of your bowel. Or you might have surgery to widen areas where your bowel has narrowed because of a stricture, or to drain an abscess. Even if all of the affected part of your bowel is removed, the condition can return in areas of your bowel that were previously healthy. Therefore, surgery isn’t a cure for Crohn’s disease.

Eight out of 10 people with Crohn's disease may need to have an operation at some point in their life. Some people may need several operations to treat Crohn’s disease.

Living with Crohn's disease

When your condition is in remission and you have few or no symptoms, you may find Crohn's disease has little impact on your day-to-day life. However, when you get a flare-up, your symptoms can make life more difficult. Frequent bouts of diarrhoea can make it harder to work. About one in 10 people who have had Crohn’s disease for longer than five years are unable to work.

You may find it helpful to see a counsellor or join a support group to meet others in a similar situation.

Reviewed by Rachael Mayfield-Blake, Bupa Health Information Team, May 2014.

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For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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