About Crohn’s Disease – Symptoms, Investigations, Diagnosis, Treatment, Causes & Facts

Crohn’s Disease is a chronic inflammatory condition of the bowel. Inflammation means the tissues involved become red, hot, swollen and painful and are unable to do their job well (which for the bowel means absorbing important nutrients from your food). It is an incurable disease which usually begins in young adulthood and lasts throughout life with episodes of disease (relapse or flares) and other episodes when the disease is under control (remission).

Fast Facts About Crohn’s Disease

  • Approximately 115,000 people suffer from Crohn’s Disease in the UK.
  • There are approximately 18,000* new cases diagnosed each year (*Figures published in NICE Guidelines 2013)
  • The number of people with Crohn’s Disease is rising, particularly among the young.
  • The illness can occur at any age but most frequently starts between the ages of 15 and 40, and later at around 60.
  • So far, the causes are not known.
  • Crohn’s Disease is a chronic (ongoing) condition.
  • At this time treatment, through medication or surgery, can help control the condition but there is no cure.

Symptoms of Crohn’s Disease

It can be difficult to diagnose Crohn’s Disease. The symptoms can vary a great deal from a patient with bloody diarrhoea and pain in their tummy to someone else who may have weight loss, a loss of appetite and a feeling of being generally unwell.

The main symptoms of Crohn’s depend on the location of the Crohn’s within the bowel but most commonly patients will get diarrhoea (sometimes with blood in), abdominal pain and weight loss. They may also feel generally ill or tired and may have a fever and feel nauseous (sick) or vomit.

The first symptoms can also be those of an acute or severe attack. For example a patient may come to hospital with pain in the bottom right hand corner of their tummy – a bit like someone with appendicitis, and may even undergo surgery to remove their appendix at which point the Crohn’s
Disease is discovered. They may come to hospital with severe pain in their tummy, vomiting and a temperature, perhaps with a lump in their tummy which their doctor can feel from the outside which is due to an abscess (infected collection inside the tummy) or very severe inflammation in the bowel.

On the other hand, the patient may come to their GP with a long history of feeling generally under the weather, tired and mildly unwell. They might have anaemia (lack of red blood cells which makes you feel tired) or weight loss (because they’re not absorbing nutrients form their food properly.

There are some features that suggest that an inflammatory bowel disease (Crohn’s or Ulcerative Colitis) might be the diagnosis. Things like having blood relatives with inflammatory bowel disease, having mouth ulcers or having problems around the anus (bottom) such as painful swellings, fissures (little tears) or abscesses (boils, collections of pus) don’t mean a patient definitely has Crohn’s but do make it a more likely diagnosis.

Investigations & Diagnosis in Crohn’s

First, most doctors will perform blood tests looking for signs of inflammation, anaemia and poor nutrition. They may also look for signs of other diseases so a wide range of blood tests is often performed at this stage. Samples of a patient’s stool (poo) are often sent to look for evidence of
infection which can cause similar symptoms, especially if there is diarrhoea.

The best tests and those most likely to make the diagnosis are those which allow doctors to look at the bowel and hopefully take biopsies (small samples of the bowel). The various imaging tests like x-rays, scans and so on are generally less unpleasant for patients but do not allow biopsies to be taken.They are sometimes good enough to make a diagnosis of Crohn’s Disease and are able to look in places that telescopes find it hard to reach like far up inside the small bowel.

A colonoscopy (telescope inside the large bowel passed up to reach the end of the small bowel, the terminal ileum) allows doctors to look at the lining of the bowel directly and see inflammation that is visible but also take biopsies which can not only see inflammation that is invisible to the naked eye, but also allow examination of the inflammation under the microscopy which helps doctors tell Crohn’s Disease apart from other causes of inflammation in the large bowel.


Before colonoscopy, patients have to drink ‘prep’ which is a strong laxative to empty the bowel completely so that the lining of the bowel can be examined. It causes diarrhoea which empties the bowel in the 24 hours prior to the test.

The colonoscope is a long, thin black telescope with a fibre optic camera on the end. It can be passed in through the anus and around the large bowel right up to the end of the small bowel (terminal ileum). Pain killers and sedative drugs are often used to make the procedure more

As well as looking at the bowel a doctor can take pictures, videos and also small biopsies – samples of the tissue taken with a little forceps (like a tiny mouth that takes a small bite of the tissue of the bowel) which can be collected and looked at under the microscope. The biopsies are examined (this is called histology) to look for features typical of Crohn’s Disease. Other diseases such as Ulcerative Colitis, some infections of the bowel and other rarer diseases can be identified by histology.


Surgery in Crohn’s Disease used to be mainly undertaken after complications (such as a narrowing or fistula) had occurred but increasingly it is believed that an early operation can sometimes help to prevent these complications and get better and longer lasting control of the disease from an earlier stage. Surgery can often greatly improve the quality of life of a person with Crohn’s Disease

  • Many Crohn’s sufferers, perhaps up to 80%, will undergo surgery of some kind during their lives.
  • Surgery does not cure Crohn’s Disease but it is designed to either treat a complication (like a fistula or stricture[narrowing]), or to prevent them.
  • After surgery, the problems the operation treated can return but some people experience long periods of remission after surgery.
  • Generally speaking surgery for Crohn’s Disease is either on the abdomen (to remove an inflamed section of intestine or to remove or widen bits of intestine with fistulas or strictures in), or around the back passage to treat fistulas or other problems in this area.
  • A stoma (colostomy or ileostomy bag) is sometimes necessary for safety and can provide a better period of relief from symptoms but it is not always needed and is often temporary when it is used.
  • Major surgery always has a long recovery time and this is particularly true in people who are underweight or already ill such as those suffering from active Crohn’s Disease before the operation.
  • Healing after surgery can be slow for Crohn’s sufferers.

Treatment with Drugs

Medication plays a large role in the management of Crohn’s Disease. Most people diagnosed with Crohn’s will have to take different types of medication for their management of Crohn’s at some stage

There are many different drugs used in Crohn’s Disease and new drugs appear on a regular basis. As, the exact cause of Crohn’s Disease is not known, most of the drugs used tend to reduce inflammation (steroids also known as anti-inflammatories) or dampen the action of the immune system (immunosuppressants or immunomodulators).

The range of disease in Crohn’s is quite large. Some people just get a bit of diarrhoea which is controlled using drugs like loperamide or codeine which simply thicken the stool (poo) and make you need to go less often. More severe symptoms may require more powerful drugs.