Crohn’s disease

Expert reviewer, Dr Ian Arnott, Consultant Gastroenterologist
Next review due August 2019

Crohn’s disease is an inflammatory condition that affects your gastrointestinal tract. It’s most common between the ages of 15 and 40 and affects both men and women equally. Symptoms may include abdominal (tummy) pain, persistent diarrhoea and feeling more tired than usual.

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About Crohn's disease

If you have Crohn’s disease, any part of your gastrointestinal tract – from your mouth to your anus (back passage) – can be affected. But most commonly, the affected areas are the final part of your small intestine (also known as your small bowel), colon and rectum. The affected (or inflamed) areas are called ‘skip lesions’, this is because they are usually separated by unaffected areas.

If you have Crohn’s disease your symptoms can often flare up and then settle down again, and may even clear up completely for a while. But Crohn’s disease cannot be cured, and your symptoms may come back (this is known as relapse).

Symptoms of Crohn's disease

If you have Crohn's disease, your symptoms can range from mild to severe and may change over time. You may have long periods of time with few, or no symptoms at all, but they may come back again after sometime.

Symptoms of Crohn's disease include:

  • diarrhoea that doesn’t clear up – sometimes containing blood or mucus
  • pain in your tummy (abdomen), which can be severe
  • excessive tiredness (fatigue)
  • weight loss
  • a fever

Crohn’s disease can also cause other problems:

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

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

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Diagnosis of Crohn's disease

Your GP will ask about your symptoms and examine you. They will also ask you about your medical and family history.

Your GP may ask for a sample of your stool (faeces) to see if you have a bacterial infection. They may also check for something called faecal calprotectin – a substance which suggests you have an inflammatory bowel condition like Crohn’s disease. Your GP will also take a blood sample 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 your 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 back passage (rectum) and into your bowel. They can then look inside your bowel and take tissue samples that can be tested in a laboratory.
  • A computerised tomography scan (CT) scan or magnetic resonance imaging (MRI) scan. These scans produce images of the inside of your tummy (abdomen). You may have a CTE (computer tomography enteroclysis or enterography) or MRE (magnetic resonance enteroclysis or enterography) scan. These scans use a contrast medium – a solution which helps parts of your abdomen, such as you small intestine, show up more clearly. If you have a CT or MR enteroclysis, your doctor passes the contrast medium through a small tube that runs from your nose, through your gullet and stomach, and into your small intestine (small bowel). If you have a CT or MR enterography, your doctor gives you a solution of the contrast medium to drink.
  • A capsule endoscopy. If you have this test, your doctor will give you a small capsule to swallow. The capsule contains a small camera that can transmit pictures of your small intestine (or small bowel) as it passes through.
  • Barium tests. These tests aren’t used as much nowadays, but may include small bowel enema or barium follow through. Both tests use barium as a contrast medium (to show up your small intestine (small bowel) more clearly) and an imaging technique called fluoroscopy. Fluoroscopy uses lots of X-ray images, which are taken and then displayed on a monitor one after the other, to create a moving image or ‘X-ray movie’.


If you have Crohn’s disease, it's important to eat a healthy, balanced diet. You may find that certain foods, such as those high in fibre, can make your symptoms worse. You should get some advice from a dietitian first, but you may find it helps if you remove these foods from your diet when your symptoms flare up.

During a flare-up, you may be able to ease your symptoms with a special liquid diet called an elemental or polymeric diet. Liquid diets are easier to digest than normal food. They help rest your bowel, improve your absorption of essential nutrients and ease any inflammation in your digestive system. For more information, see our FAQ on Special foods.

Treatment of Crohn's disease

Crohn's disease can’t be cured. But there are treatments you can try 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.


Medicines can help to prevent a flare-up or ease your symptoms. It’s important to keep taking any medicines you’ve been prescribed to keep your symptoms under control. 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.

  • Corticosteroids (such as prednisolone and budesonide). These ease inflammation, but you usually only take them for a short time during a flare-up. This is because they can cause side-effects such as diabetes, infections, cataracts, high blood pressure and osteoporosis. Immunosuppressants (such as azathioprine, mercaptopurine and methotrexate). These dampen down your immune system and reduce inflammation, but they may make you more likely to catch infections.
  • Antibiotics (such as metronidazole or ciprofloxacin). Your doctor may offer you these if the area around your anus (back passage) is affected. They may help to reduce your risk of developing an infection and treat infections if they do occur.
  • Biological therapies (such as infliximab, vedolizumab or adalimumab). Your doctor will usually only prescribe these if your symptoms don’t settle with other treatments.

Your doctor may also suggest that you take medicines to ease specific symptoms, such as diarrhoea or cramping pains. 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, as these can make your symptoms worse. Always read the patient information leaflet that comes with your medicine. If you have any questions, ask your pharmacist or doctor for advice.


Surgery isn’t a cure for Crohn’s disease, but your doctor may suggest you have an operation if you’ve tried several different medicines and they haven't worked.

You may have an operation to remove a severely inflamed part of your bowel. Or you may have surgery to widen areas where your bowel has narrowed because of a stricture. You may also need surgery if you have complications of Crohn's disease, such as an abscess or fistula.

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

Causes of Crohn's disease

It’s not clear why some people develop Crohn’s disease and others don’t, but your family history may increase your risk. Up to one in five people with Crohn’s disease have a close relative who also has the condition. It’s thought that people who are at an increased risk of Crohn’s disease have an abnormal immune reaction to certain bacteria or viruses in their bowel.

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

Complications of Crohn's disease

Complications of Crohn’s disease include the following.

  • A fissure. This is a tear in the wall of your anus that can hurt and bleed when you go to the toilet.
  • A narrowing (stricture) in your bowel. A stricture can block part or all of your bowel. It can cause pain, vomiting and swelling in your tummy.
  • An abscess (collection of pus). If inflammation causes an ulcer in your bowel wall, a hole may develop there. The contents of your bowel can leak through the hole and cause an abscess. The abscess may then spread 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 absorbs vitamins and minerals, especially iron, folic acid and vitamin B12, from food.
  • Bowel cancer. Crohn's disease increases your risk of developing bowel cancer. See our FAQ on Bowel cancer risk for more information.

Living with Crohn's disease

If your symptoms are mild or clear up for a while, you may find Crohn's disease has little impact on your day-to-day life. But when you have a flare-up, your symptoms can make life more difficult. If you have diarrhoea regularly, this can make your skin sore. It can also make it harder for you to work. You may need to take time off or cancel social arrangements. Telling your friends, family and work colleagues about Crohn’s disease will help them to give you any support your need.

It’s important to keep taking your medicines so that your symptoms are under control. If you don’t have any symptoms, your doctor may still recommend that you have a check-up every six to 12 months.

If your Crohn’s disease stops you eating properly, this can make you lose weight and feel very unwell. Your doctor or dietitian may recommend that you take dietary supplements to make sure you’re getting all the essential nutrients your body needs.

Crohn’s disease can increase your risk of osteoporosis. This is when your bones become fragile and weak. You may be advised to have your bone density and your risk of a bone fracture, checked. Corticosteroid medicines can also increase your risk of osteoporosis. If you take these regularly, you may be recommended to take calcium and vitamin D supplements to keep your bones healthy.

Stress can make your symptoms worse. Relaxation therapies may help to reduce the risk of a flare-up. Rest if you’re feeling tired or having a flare-up. But make sure you also do some form of activity every day to stop you getting bored or frustrated.

Having a long-term medical condition, such as Crohn’s disease, can make you feel a bit down. It can also affect your relationships and may lead to depression. It’s important to discuss your feelings with your doctor or specialist nurse. You may find it helpful to see a counsellor or join a support group to meet others in a similar situation.

Frequently asked questions

  • If you have Crohn’s disease, this can increase your risk of getting bowel cancer. You’re more likely to develop bowel cancer if you’ve had Crohn’s disease for a long time.

    Your risk depends on how bad the inflammation is in your bowel, and how much of your bowel is affected. If you’re unsure, ask your doctor to explain this risk to you.

    Taking your medication as prescribed by your doctor (to reduce the inflammation in your bowel) may help to decrease your risk of bowel cancer. But if you have Crohn’s disease, it’s important to have your bowel examined regularly. This can help to detect bowel cancer early, meaning you can have treatment before the cancer has a chance to spread. Your first screening will be 10 years after you’re first diagnosed. Your doctor then examines your bowel:

    • every five years if your risk of developing bowel cancer is low
    • every three years if your risk of developing bowel cancer is intermediate
    • every year if your risk of developing bowel cancer is high

    You'll need to have a colonoscopy to check your large bowel for signs of cancer. This involves using a narrow, flexible, tube-like telescopic camera called a colonoscope. If your doctor sees any possible signs of cancer, they’ll take a small sample of tissue that’ll be tested in a laboratory.

    If you’re having your bowel examined regularly, you probably won’t need to have additional screening for bowel cancer as part of the NHS Bowel Cancer Screening Programme. This screening is offered every two years to everyone aged 60 to 74, including people who don’t have any bowel problems. A new type of screening (bowel scope screening) is now being introduced for all men and women at the age of 55. It's being introduced across England, but is not yet available everywhere. For more information talk to your GP.

    If you have any questions about Crohn's disease and bowel cancer, speak to your GP.

  • If you smoke, you’re three to four times more likely to develop Crohn’s disease than someone who doesn’t smoke. If you continue to smoke after being diagnosed with Crohn’s disease, you’re more likely to have severe symptoms. And if you continue to smoke after you have surgery for Crohn’s disease, your symptoms are also more likely to return.

    Stopping smoking can also help reduce your risk of future flare-ups. Ask your pharmacist about how to quit smoking. You can be referred to NHS Stop Smoking Services for support and advice. You’re more likely to quit with support from a healthcare professional and your family and friends.

  • If you have Crohn’s disease, you should eat a healthy, balanced diet, but you don’t usually need special foods. You may find eating low-fibre foods or a liquid diet can help to ease your symptoms during a flare-up.

    Crohn’s disease can affect how well your body absorbs vitamins and minerals from food. So it’s important to eat a healthy, balanced diet to make sure you’re getting all the nutrients you need. You may find that certain foods, such as high-fibre foods, stringy beans, meat gristle and nuts, make your symptoms worse. If this happens, it may help if you stop eating these foods when your symptoms flare up. Some people with Crohn’s disease don’t absorb fat properly and need to eat a low-fat diet. But you shouldn’t cut out any whole food groups without speaking to your doctor or a dietitian first.

    During a flare-up, eating low-fibre foods or a liquid diet (called an elemental or polymeric diet) may help your symptoms. Liquid diets give your bowel a rest and can ease any inflammation in your digestive system. Your doctor may also suggest a liquid diet if you have a flare-up but can’t or don’t want to take any medicines.

    For more information about what to eat or about liquid diets, talk to your dietitian or doctor.

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  • Reviewed by Laura Blanks, Specialist Health Editor, Bupa Health Content Team, August 2016
    Expert reviewer, Dr Ian Arnott, Consultant Gastroenterologist
    Next review due August 2019

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