Crohn’s disease is a long-term condition that causes inflammation of the lining of the digestive system.
Inflammation can affect any part of the digestive system, from the mouth to the back passage, but most commonly occurs in the last section of the small intestine (ileum) or the large intestine (colon).
Common symptoms of Crohn’s disease include:
Over time, inflammation can damage sections of the digestive system, resulting in additional complications, such as narrowing of the colon.
People with Crohn’s disease sometimes go for long periods (weeks or months) without symptoms, or with very mild symptoms. This is known as remission. Remission can be followed by periods where a person’s symptoms flare up and become particularly troublesome.
What causes Crohn’s disease?
The exact cause of Crohn’s disease is unknown. However, research suggests that a combination of factors may be responsible. These include:
- genetics - genes that you inherit from your parents may increase your risk of developing Crohn’s disease
- the immune system - it seems that the immune system (the body’s natural defence against infection and illness) is responsible for the inflammation in the digestive system
- previous infection - a previous infection may trigger an abnormal response from the immune system
- environmental factors - Crohn’s disease is most common in westernised countries, such as the UK, and least common in poorer parts of the world, such as Africa, which suggests the environment has a part to play
- smoking - smokers with Crohn’s disease usually have more severe symptoms than non-smokers
Read more about the potential causes of Crohn’s disease.
A colonoscopy is the most common test used to diagnose Crohn’s disease. There are several other tests that may be used to help rule out other conditions that might be causing your symptoms.
Treating Crohn’s disease
There is currently no cure for Crohn’s disease so the aim of treatment is to control the symptoms. Several different types of medication can be used to reduce your symptoms. In many cases, surgery will also be needed.
Around 60-75% of people with Crohn’s disease need surgery to relieve their symptoms, repair damage to their digestive system and treat related complications.
Read more about treating Crohn’s disease.
If your symptoms are severe, your doctor may recommend an elemental (liquid only) diet on a temporary basis.
Although there is currently no clinical evidence, some people find that certain foods, such as dairy products, fatty foods and spicy foods, can worsen symptoms in some people. Therefore, eliminating them from your diet may help.
Read more about diet and living with Crohn's disease.
Complications of Crohn’s disease
The two most common complications associated with Crohn’s disease are bowel obstruction and fistula.
Bowel obstruction
Severe inflammation can cause sections of the bowel to narrow and harden, causing the contents of the bowel to become stuck.
Fistula
A fistula is a channel that develops between the end of the bowel (anal canal) and the skin near the anus. Surgery is usually required to treat a fistula.
If you think that your bowel is obstructed, contact your GP immediately or phone NHS Direct on 0845 46 47.
Who is affected by Crohn’s disease?
Crohn’s disease is a rare condition. In the UK it is estimated that for every 100,000 people there will be seven new cases of Crohn’s disease a year. There are currently around 90,000 people living with Crohn’s disease in the UK.
Most cases of Crohn’s disease first develop in people who are between 16 and 30 years of age. A large number of cases also develop in people between the ages of 60 and 80. However, Crohn's disease can affect people of all ages, including children. It affects slightly more women than men.
Crohn’s disease is more common in white people than in black or Asian people. It is most prevalent among Jewish people of European descent.
