Crohn's disease is a chronic (long-term) condition that causes inflammation of the lining of the digestive system. Inflammation usually occurs in the ileum (the last section of the small intestine) or the colon (the large intestine). However, inflammation can occur anywhere in the digestive system, from the mouth to the anus (back passage).

Over time, the inflammation that is caused by Crohn's disease can damage sections of the digestive system, causing additional complications, such as narrowing of the colon.

Common symptoms of Crohn's disease include:

• diarrhoea
• abdominal pain
• fatigue

The cause of Crohn's disease is unknown. However, research suggests that a combination of environmental and genetic factors is responsible for the onset of Crohn's disease.

How common is Crohn's disease?

Crohn's disease is a rare condition. It is estimated that for every 100,000 people there will be seven new cases of Crohn's disease a year.

Most cases of Crohn's disease first develop in people who are between 16 and 30 years of age, although the condition can affect people of all ages, including children.

Crohn's disease is more common in white people than in black people, or those of Asian descent. The condition is most prevalent among Jewish people of European descent. Crohn's disease affects slightly more women than men.

Outlook

The outlook for Crohn's disease is highly variable. People can have long periods of remission that last for weeks or months where they have no, or very mild, symptoms, followed by periods where their symptoms flare up and are particularly troublesome.

There is currently no cure for Crohn's disease. However, medication is available that can be used to treat the symptoms and prevent them from returning.

About 80% of people with Crohn's disease will require surgery to relieve their symptoms, repair damage to their digestive system and treat complications of the condition.