Crohn's Disease

Other name: Inflammatory Bowel Disease

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract which can affect any part of the gut, from the mouth to the anus, but commonly affects the small and large intestine. It is one of the group of inflammatory bowel diseases (IBD) which run in families. Crohn's disease and ulcerative colitis are both associated with certain genetic diseases. However, the cause of IBD is unknown.

Crohn's disease increases the risk of colon cancer due to the constant inflammation and healing.

Smokers are at an increased risk of developing Crohn's disease.


Chronic inflammation results in pain, diarrhoea and weight loss, as well as other symptoms. Symptoms and signs vary according to the affected site and how much of the gut is involved.

If the small bowel is involved, patients may get abdominal pain after meals, diarrhoea and weight loss. With large bowel involvement, diarrhoea and rectal bleeding is common.

Symptoms in Crohn's disease may begin insidiously and the diagnosis is often delayed. Systemic features are common (fever, weight loss, etc) and perianal disease (lesions, abscesses) is a frequent early clue to the diagnosis.

Anaemia may also be diagnosed because of Crohn's disease.


The diagnosis is made by a combination of x-rays, endoscopy, colonoscopy and biopsies. Exclusion of infective causes of diarrhoea and bleeding is important and hence stool culture and examination may also be performed. A full blood count may also be done to see if the patient is anaemic because of low iron, folate or vitamin B12, plus to look for signs that an inflammatory process is occurring.

Medical Treatment

Although there is at present no cure, the disease can be successfully treated with medication and occasionally with surgery.

Medications can be used either for acute episodes or for long term use and treatment depends upon the site of involvement and the severity of the disease. These include corticosteroids, anti-inflammatories (e.g. mesalazine), immunomodulators (e.g. azathioprine), and biologics (e.g. infliximab).

Some general measures can be done to correct things that Crohn's disease may have caused - such as anaemia, malnutrition or dehydration. Patients also need emotional support, both at the initial diagnosis and during relapses, and self-help groups are important (see links below).

A low fibre diet may reduce the symptoms in patients with significant small bowel disease. Vitamin and mineral supplements including iron, folate and vitamin B12 may be needed.

Most patients with Crohn's disease lead a relatively normal life despite the chronic nature of this condition.