Inflammatory bowel disease is an umbrella term that covers both ulcerative colitis and Crohn’s disease. Both may cause similar symptoms but they can usually be differentiated by looking at which part of the digestive system is affected.

Crohn’s disease can affect any section of the digestive system. The severity of inflammation can vary and people with mild symptoms can often go undiagnosed for some time.

At the other end of the spectrum, severe Crohn’s disease can make people very unwell. The key to effective management relies on an accurate diagnosis and a detailed assessment of the disease.

What is Crohn's disease and what causes it?

Crohn's disease causes the small intestine (the jejunum and ileum) or the large intestine (the colon) to become inflamed. Inflammation is most common in the last part of the small bowel (the terminal ileum) and the first part of the large bowel (the caecum). However, Crohn's can cause any part of the digestive system to become inflamed, from the mouth, right through to the rectum and anus.

We do not yet understand fully what causes the disease but current theories suggest that the body's immune system may be overreacting to components of gut bacteria. This can lead to bowel inflammation in people with a genetic predisposition.

Recognising the symptoms of Crohn's disease

Most people with Crohn's disease experience chronic diarrhoea, often at night as well as during the day. Other common symptoms include weight loss, abdominal pain and rectal bleeding. 

Crohn's disease is not life-threatening but it can cause serious complications such as blockages in the bowel or fistulas; these are abnormal connections form the bowel to other organs such as the skin or bladder. Making an accurate diagnosis and treating it appropriately can sometimes prevent some of these complications.

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