What is Ulcerative colitis?

Ulcerative colitis and Crohn’s disease are the main forms of inflammatory bowel disease (IBD). Both are long-term diseases that cause visible inflammation of the digestive tract due to abnormal immune activity rather than infection. Each condition has a distinct pattern, which can lead to different problems in the future. So what is ulcerative colitis and what makes it different to Crohn’s disease?


The main distinguishing features of Crohn’s disease are the location and severity of the inflammation. In Crohn’s disease, the inflammation can involve any part of the digestive tract though it most commonly affects the small and/or large intestines. Some parts of the digestive tract are affected while others may be unaffected. Unlike ulcerative colitis, Crohn’s disease affects all layers of the intestinal wall, not just the lining.

Generally, the symptoms of Crohn’s disease and ulcerative colitis are similar, including stomach pain, diarrhoea, a sudden urgency to use the toilet, tiredness, weight loss and a loss of appetite. Some people may experience fever, mouth ulcers, nausea and vomiting. People with Crohn’s disease may have pain or swelling around the anus. Other parts of the body may become affected too, causing rashes, joint pain and inflammation of the eye.

Not everyone will experience all of these symptoms and they may come and go over time. People may go through periods when their symptoms are at their most severe, called flare ups, and time when they experience very few or no symptoms at all, called remission.

Inflammation is a normal part of the body’s self defence system. In Crohn’s disease, it is believed that the immune system of certain individuals overreacts to environmental factors, attacking healthy tissue and causing inflammation and ulceration. There is no way of telling who will be affected, but people with a family history are more likely to develop Crohn’s disease and it is usually identified in younger people.

In moderate or severe Crohn’s disease, ulcers can become larger, deeper and more inflamed, which can cause the intestinal wall to thicken and block the passage of food. In some cases these ulcers can become so severe they break through the wall causing complications that may require surgery.

While there is no cure for Crohn’s disease, medical treatments can help manage the disease and improve quality of life.