Guts UK raises concern over increase in microscopic colitis cases

Apr 17, 2023

  • Resource for patients published by the national charity Guts UK highlights the increase in microscopic colitis cases in the UK.
  • The charity has raised concerns about the number of people suffering with a misdiagnosis or living with undiagnosed and debilitating symptoms. 
  • 17,000 new cases are being diagnosed each year, but the real number could be a lot higher. 

Experts have raised concerns about increase in microscopic colitis microscopic colitis (many undiagnosed), a debilitating bowel condition thought to affect thousands of adults in the UK. The national charity Guts UK has published a resource for patients during Microscopic Colitis Awareness Week to raise awareness of the disease and is calling for more research into prevention, faster diagnoses and developments in treatments.

Microscopic colitis is an inflammation of the large intestine (bowel) that causes persistent, frequent and watery diarrhoea (throughout the day and night), stomach pain, fatigue, faecal incontinence and weight loss. It is frequently misdiagnosed and the prevalence of the condition is higher than previously thought (1).

Scientists estimate that around 67,000 people are living with microscopic colitis in the UK or at least 1 in 1,000 adults (2,3). 17,000 new cases are being diagnosed each year, but the real number could be a lot higher because it’s often underreported and misdiagnosed (4).

A 2012 study showed that one in three patients with microscopic colitis were initially incorrectly diagnosed with Irritable Bowel Syndrome (IBS) and “a large, hidden burden of undiagnosed and untreated microscopic colitis likely exists in the UK population owing to systematic misdiagnosis of microscopic colitis as IBS” (5,6).

Despite the missed diagnoses, cases of microscopic colitis are on the rise globally. The UK incidence rate of microscopic colitis in 2016 was twice that observed in 2009 (7).

Microscopic colitis is a leading cause of diarrhoea in older adults and it can have a devastating impact on a person’s quality of life. Many people suffer with the condition for years but the correct diagnosis and treatment can make a huge difference (8).

“I spent 12 years living with undiagnosed microscopic colitis. On my worst days, I was going to the toilet 30 to 40 times per day and suffered from awful stomach cramps. I ended up becoming agoraphobic because I was so distressed. I went to the doctor again and again but it took me all these years to get a correct diagnosis. I even went to A&E but was told it was ‘just IBS’ and I was sent home with no treatment plan.

“By 2022 I became scared of eating in case it triggered symptoms and my flare ups were becoming more frequent. I felt more tired than I’d ever felt in my life and completely hopeless. I was also trying to parent my baby son while living with the condition.

“The treatment I have received after getting my diagnosis has changed my life. I feel like I’ve regained some semblance of normal.”

Victoria, age 33 from London, was diagnosed with microscopic colitis last year. She said:

Microscopic colitis is named because, unlike other inflammatory bowel diseases, like Crohn’s disease or ulcerative colitis, it can’t be diagnosed with a colonoscopy alone and a sample of tissue taken from the bowel must be examined under a microscope to identify the condition. Because of this, the disease is often misdiagnosed.

Julie Harrington, CEO of Guts UK, commented on the increase in microscopic colitis cases:

“It’s terribly sad that thousands of people are suffering with the debilitating symptoms of microscopic colitis. Most people with the condition can be easily treated with a course of gut-specific steroids or with symptom-relieving medicines but getting a diagnosis is the first, essential step.

“People living with the condition but without the benefit of a correct diagnosis and effective treatments often can often feel very isolated due to the urgent nature of their symptoms and their need to be near to toilet facilities at all times. We know that this can also have a detrimental effect on their mental wellbeing. 

“The rates of microscopic colitis are increasing and are likely to grow further as the population ages, so it’s crucial that we identify risk factors, provide specific training for healthcare providers, continue to raise awareness and invest in research to improve diagnosis and treatments.” 

Professor Chris Probert, Professor of Gastroenterology at the University of Liverpool said:

“Undiagnosed microscopic colitis can cause years of unnecessary suffering. The diarrhoea symptoms tend to be very severe and houselimiting leading to considerable distress for patients.

“It’s not clear why cases of the condition are on the increase but it is likely to be due to a mixture of increased awareness of symptoms leading to more diagnoses and environmental factors such as a potential side effect of common prescription drugs such as some antidepressants. 

“The good news is that effective treatments are available so people experiencing symptoms could benefit enormously by talking with their GP.” 

Resources published in March 2022 by Guts UK to raise awareness of microscopic colitis showed that women are 700% more likely than men to suffer with the condition. 

The causes of microscopic colitis are still unclear. As it is a relatively new disease (first described in 1976) it has led to a presumption that it is environmental as opposed to genetic factors that are responsible for its occurrence. 

Anyone experiencing symptoms is advised to see their GP, contact Guts UK for more information or visit

Read more news from the Bowel Interest Group.

  1. Undiagnosed microscopic colitis: a hidden cause of chronic diarrhoea and a frequently missed treatment opportunity: 
  2. Aprox. 67,000 people are living with Microscopic Colitis in the UK – around 58,600 women and 8,400 men.
  3. Microscopic colitis includes two related inflammatory bowel disorders, lymphocytic colitis and collagenous colitis that have a combined prevalence of 103 cases per 100 000 population: May 2019.
  9. 87.5% of people suffering with the condition are female – most of whom are diagnosed between the ages of 50 and 70.