About Crohn’s and Colitis

About Crohn’s and Colitis

Crohn’s disease and Ulcerative Colitis are two types of inflammatory bowel disease (IBD). Both are lifelong conditions which cause inflammation in parts of the digestive system, and while they’re different, they have a lot in common.

1 in 100 people have Crohn’s or Colitis in the UK which means over 500,000 people in the UK are known to be living with the disease, and many live with undiagnosed Crohn’s or Colitis. Because the nature of the symptoms can cause embarrassment, they don’t get discussed and sadly, that means many people are suffering in silence.

According to a 2019 study by the University of Edinburgh, Edinburgh has some of the highest known rates of inflammatory bowel disease in the world. One in 125 people in Lothian have Crohn’s or Colitis, and the number is predicted to rise to one in 98 by 2028. Further research is expected to find that this figure will apply to the rest of Scotland and the UK too.


While each person has a slightly different set of symptoms, the first signs of Crohn’s and Colitis are very similar and usually come on gradually. They can include:

  • Sudden diarrhoea
  • Very frequent bowel movements
  • Rectal bleeding
  • Abdominal cramps
  • Weight loss
  • Fever
  • Tiredness

Symptoms can be mild or more severe. At their worst, they can be life-threatening and require hospital treatment to prevent dehydration and serious complications.

The symptoms can significantly impact on daily life; some people experience them every day while for others, they come and go. When symptoms are present, they’re referred to as flare-ups and the periods during which they settle are known as remission. It’s not unusual to go for weeks or months with very mild symptoms only to then experience a severe flare-up.

Despite decades of research, it’s still not clear what the exact causes are of the disease, who it’s most likely to affect and the most effective way to manage it long-term. Most importantly, there’s no cure yet.


Crohn’s disease most commonly affects the last section of the small intestine and the large bowel, and inflammation can spread deep into the layers of the intestinal tissue. However, inflammation can appear anywhere in the digestive system, from the mouth to the anus; usually, there are healthy areas of tissue in between the inflammation. 

Symptoms differ depending on which part of the digestive tract is affected. While the most common include sudden diarrhoea, stomach pain, blood in stools, fatigue and weight loss, other symptoms can be present too. Many people experience fever, joint aches, areas of red, swollen skin (often on the legs), sore and red eyes, nausea and sickness too.


Unlike Crohn’s disease, Colitis only affects the large intestine (colon), and the outer layer of the colon lining, called the mucosa. Inflammation is continuous; there aren’t any healthy spots in between. In some types of Colitis, small ulcers can develop on the lining too, which can bleed and produce pus. 

The severity of symptoms depends on how much of the colon and rectum is inflamed and how acute the inflammation is. Recurring diarrhoea, stomach pain, extreme fatigue and frequent bowel movements are common in most cases of Colitis. Rupture of the colon is a real and serious risk too.


The exact cause is unknown, however research points to four possible factors: 

1. A condition which causes the body’s immune system to attack healthy tissue as well as fight infections. It’s not yet known what causes the body’s defence mechanism to react in this way. 

2. Genetics seem to play a part in the likelihood of the disease developing. One in four people with Crohn’s or Colitis has a family history of the condition and research has identified several genes which make it more likely to develop. Many of the identified genes are linked to the immune system too.

3. Presence of bacteria also appears to be linked to onset. A previous stomach bug and abnormal balance of bacteria in the gut are thought to be potential triggers. 

4. Environmental factors have also been studied, and it seems that where and how you live could influence the likely development of the condition. For instance, the condition is more common in some urban areas of western Europe and America.


The symptoms are similar to many other conditions and can make diagnosis difficult. A thorough health check is usually carried out by a GP to begin with and is likely to cover symptoms, medication, diet and family medical history. Further investigations by a GP might include:

  • Blood samples to check for anaemia and inflammation anywhere within the body
  • Stool sample to rule out infections and check for inflammation
  • Stomach examination to check for tenderness

If either condition is suspected, or tests prove inconclusive, a referral is made for further investigations. These might include:

  • Sigmoidoscopy, colonoscopy or endoscopy to ascertain severity and extent of inflammation and to take a biopsy of the relevant tissue


While there’s no cure yet, treatment is available to alleviate or control symptoms and reduce flare-ups. Patients are cared for by a team of healthcare professionals, including their GP, specialist nurses and IBD doctors, who will advise on the best course of treatment.


Several medicines can be used to reduce inflammation, which in turn gives damaged tissue time to heal. They fall into four categories:

  • Aminosalicylates, which work on the lining of the digestive tract to reduce inflammation, can be used ongoing to prevent flare-ups usually for Colitis
  • Steroids are a more potent medicine used to lessen inflammation, however, with more serious side effects, they’re used as a shorter-term treatment
  • Immunosuppressants are often used alongside steroids to reduce immune system activity and minimise inflammation returning after the steroid treatment stops
  • Biological medicines work on the immune system too by blocking the proteins used by the immune system to stimulate inflammation


Special diets can be helpful in managing the disease. Traditionally a liquid-only diet has been used; however, more recently, a specially directed solid food diet has been found to be effective too.


In cases where symptoms are severely impacting the quality of life, where medication isn’t effective, or a complication occurs, surgery may be necessary. Up to 45% of people with Colitis and 75% of people with Crohn’s disease eventually need surgery. Crohn’s is treated by removing a part of the digestive system, while the colon is removed in Colitis patients.

Lifestyle changes

A healthier lifestyle can help in reducing and managing flare-ups. Healthier eating, regular exercise and not smoking can all make a difference. Stress is also thought to contribute to flare-ups, and so practising relaxation techniques can help.


Both are chronic conditions and so need long-term management. A normal, healthy life is possible with IBD. However, some adjustments are likely to be required.

Flare-ups can be disruptive and so last-minute changes to plans are common. Often, routines need to be altered too. The impact on day-to-day life can lead to stress and anxiety, so it’s essential to put regular practices in place to manage the effect the disease can have psychologically.

Many people living with IBD develop health conditions outside of the digestive system too. There’s an increased risk of conditions including arthritis, osteoporosis (weakening of the bones), liver inflammation and damage, gallbladder disease and bowel cancer. Skin and eye problems, blood clots and anaemia are more likely too. 

That’s not to say that every person living with Crohn’s or Colitis is going to be affected by other conditions, and regular checks with their healthcare team are vital to staying in the best health possible.

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