Crohn’s Disease

  • Reference Number: HEY-063/2015
  • Departments: Gastroenterology


This leaflet has been produced to give you general information about your condition.  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and your doctor but may act as a starting point for discussion.   If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team caring for you.

What is Crohn’s Disease?

It is a chronic inflammatory disease, which can affect any area of the digestive tract from mouth to anus. The inflammation extends through all layers of the gut wall and is patchy in distribution with areas of normal tissue between the affected parts.

The most commonly affected sites are the terminal ileum (the lower part of the small intestine) and the large intestine. It frequently affects the area around the anus.

The symptoms of Crohn’s disease vary according to its site, (i.e. small or large intestine) and severity. However, the following features can occur:

  1. Diarrhoea – sometimes, but not always with blood.
  2. Abdominal pain and tenderness over the intestine.
  3. Weight loss, and in children failure to grow.
  4. Fever.
  5. Tiredness.
  6. Sores and abscesses around the anus, which have a discharge. These may be the first signs of the disease in some patients.
  7. Other symptoms not involving the intestine may occur:
  • Sore mouth due to ulcers on the tongue or inside the cheek.
  • Painful, inflamed eyes (uveitis).
  • Painful, stiff or swollen joints, e.g. arthritis, ankylosing spondylitis.
  • Sore, red lumps on the skin (erythema nodosum).

Why does inflammation occur?

Inflammation is the normal protective reaction of the body to an infective organism, antigen (a foreign agent in the body) or tissue injury. A healthy body can control the inflammation using internal anti-inflammatory mechanisms. In IBD, there is an imbalance between the cells that cause inflammation and those that protect against inflammation and the body cannot control the inflammation.

What causes Crohn’s Disease?

Despite continued research since the 1930’s, the cause of Crohn’s disease has not as yet been identified. There are a number of factors that are believed to play a role in Crohn’s disease, which are:


Research has shown that you are more susceptible to Crohn’s if you have a family member with the condition. The risk is greatest when it is a brother or sister affected. Studies involving twins have shown that identical twins are more at risk than none identical twins.


You cannot ‘catch’ Crohn’s disease from another person or object. Some cases start following Gastroenteritis. Some researchers believe that Crohn’s is an unusual immune response to an organism that is relatively harmless, while others believe that Crohn’s is possibly due to bacteria in the gut. These bacteria may produce toxins (poisons) which attack the intestine wall causing damage. If these toxins were absorbed into the blood stream it may explain why symptoms are seen elsewhere in the body.

Immunological factors

In Crohn’s disease the body’s immune system is activated by intestinal bacteria and may be involved in causing damage to the lining of the intestine. Many of the drugs used in Crohn’s disease are aimed at the immune system. Immunological changes are likely to be a result of the Crohn’s disease rather than the cause of it.

Dietary factors

Some patients find that their Crohn’s disease is better if they avoid certain foods such as wheat, yeast or milk. However, many other patients with the disease are able to eat these foods. It is possible that the breakdown of certain foods (perhaps by bacteria) in the large intestine plays a part in Crohn’s disease.

Psychological factors

Some people find that during times of stress, they may experience a flare-up of symptoms.

How will Crohn’s Disease be diagnosed?

You may go to your GP with some of the symptoms listed above. You will be referred to a hospital specialist who may arrange a number of tests.  Your condition will be diagnosed using a variety of methods, which may include:

  • Blood tests (these do not diagnose Crohn’s disease).
  • Colonoscopy (camera into whole of the large bowel).
  • Sigmoidoscopy (camera into left side of bowel).
  • Stool tests.
  • CT scan or MRI scan.
  • X-ray investigation.

Please speak to the IBD specialist nurse for further information.

What treatments will I receive?

There is no cure for Crohn’s but large proportions of patients achieve remission. The aim of treatment is to keep you in remission and to control any flare-up of symptoms and avoid complications in the long term. Treatment options include; medications, diet, and surgery.


There are a variety of medications that may be used either on their own or in combination.
There are information sheets available relating to these medications. You can speak with the Inflammatory Bowel Disease Nurse for more information.


People sometimes find that certain foods cause a flare-up of their symptoms – in this case the food should be avoided. Care should be taken that the nutrients lost from that food source is gained from another type of food. If you find that you have to restrict a large number of foods, you may need to see a dietician for specific advice regarding your dietary intake. At times you may find it difficult to eat adequate amounts, especially if you are suffering from a bad taste in the mouth or mouth ulcers, abdominal pain, loose stools. During these periods, it is important that you eat high protein and high carbohydrate foods; this is to avoid malnutrition. A change in diet may be tried either instead of or as well as medication. There are specially designed liquid foods that you can drink that allow the bowel some time to rest and recover from a ‘flare-up’.

Occasionally, it may be advised that all oral food and drink is stopped and replaced by a special type of ‘drip food’. Food will be reintroduced when the flare-up has subsided.


About half of all patients may need surgery at some point in their life time but this frequency is reducing now with improvements in medical treatment. On the whole, surgery is best avoided in Crohn’s disease, as it does not cure Crohn’s disease and often the disease recurs at some later stage. However, there may be occasions where there is no alternative to surgery. For example, if there is a blockage (obstruction) of the intestine, a large abscess or other complications.

Smoking cessation

It is very important to stop smoking tobacco products as soon as possible. Tobacco delays the healing process in Crohn’s disease. It is proven conclusively that Crohn’s disease patients who are smokers have a more severe course of disease, have poor response to medications and are about 75 times more at risk of having surgery.

Useful contacts

Crohn’s & Colitis UK


European Federation of Crohn’s and Ulcerative Colitis Associations (EFCCA)


Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact IBD Nurse Specialists on telephone number (01482) 608982.

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

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We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

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