Microscopic Colitis: Symptoms, Treatment and UK Online Doctor Guide

Microscopic colitis is a type of inflammatory bowel disease (IBD) that causes persistent, non-bloody, watery diarrhoea. While more well-known conditions like Crohn’s disease or ulcerative colitis cause visible inflammation or ulcers in the bowel lining, the changes associated with microscopic colitis can only be seen when a small sample of bowel tissue (a biopsy) is examined under a microscope.

There are two primary types of microscopic colitis: lymphocytic colitis and collagenous colitis. In lymphocytic colitis, there is an increased number of white blood cells (lymphocytes) in the lining of the colon. In collagenous colitis, the layer of collagen (a fibrous protein) under the epithelium becomes thicker than normal. According to the NHS and the British Society of Gastroenterology (BSG), the management for both types is largely the same, and the symptoms are often identical.

The hallmark symptom of microscopic colitis is chronic, watery diarrhoea that is typically not accompanied by blood. This can come on suddenly or gradually and may be frequent—sometimes occurrring up to 10 or more times a day. Other symptoms common among UK patients include:

• Urgent need to use the toilet (bowel urgency).
• Waking up during the night to pass stool (nocturnal diarrhoea).
• Abdominal pain, cramping, or bloating.
• Weight loss and fatigue.
• Dehydration due to fluid loss.
• Faecal incontinence in severe cases.

Because these symptoms overlap significantly with Irritable Bowel Syndrome (IBS), many patients are initially misdiagnosed. However, nocturnal diarrhoea is often a key clinical indicator that the issue is inflammatory rather than functional IBS.

The exact cause of microscopic colitis is not fully understood, but it is believed to involve an overactive immune response in the gut. Several risk factors have been identified through NICE (National Institute for Health and Care Excellence) guidelines and clinical research:

Age and Gender

It is most frequently diagnosed in adults aged 50 to 70 and is significantly more common in women.

Medication Links

Certain medications are known triggers. These include Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) like ibuprofen or aspirin, Proton Pump Inhibitors (PPIs) such as lansoprazole, and some antidepressants (SSRIs).

Smoking

Evidence suggests that smoking increases the risk of developing microscopic colitis and may cause symptoms to start at a younger age.

Autoimmune Conditions

People with existing autoimmune diseases, such as coeliac disease, Type 1 diabetes, or rheumatoid arthritis, have a higher prevalence of the condition.

If you present with chronic watery diarrhoea, a GP will typically start by ruling out infections and coeliac disease via stool and blood tests. If microscopic colitis is suspected, a referral to a gastroenterologist is required. The gold-standard diagnostic tool is a colonoscopy or flexible sigmoidoscopy.

During this procedure, the bowel lining often appears entirely healthy to the naked eye. This is why biopsies must be taken from multiple parts of the colon. A pathologist then examines these samples to confirm the presence of microscopic inflammation. Under NHS guidance, once diagnosed, your specialist will work with you to find a treatment plan that induces remission.

Treatment aims to stop the diarrhoea and allow the bowel lining to heal. Lifestyle adjustments are often the first step, including stopping smoking and avoiding trigger medications like ibuprofen.

Budesonide

Budesonide is the first-line medical treatment recommended by NICE. It is a corticosteroid that works locally in the bowel, meaning it has fewer side effects then systemic steroids like prednisolone. Most patients notice a significant improvement within a few days to weeks.

Other Treatments

• Anti-diarrhoeals: Medications like loperamide may be used for mild cases.
• Bile acid sequestrants: These can help if bile acid malabsorption is contributing to the symptoms.
• Dietary changes: Reducing caffeine or alcohol can help manage bowel urgency.

Dealing with chronic diarrhoea can be distressing and disruptive to daily life. You can speak to a GP online UK to discuss your symptoms if you have been experiencing changes in your bowel habits for more than four weeks. An online doctor can help by:

• Assessing your symptoms and medical history to distinguish between IBS and potential inflammatory causes.
• Reviewing your current medications to see if common triggers like PPIs or NSAIDs are involved.
• Ordering private blood or stool tests to rule out infections or malabsorption.
• Providing a referral letter to a gastroenterologist for further investigation (e.g., biopsy).
• Issuing sick notes if your symptoms are making it impossible to attend work or university.

Online consultations offer a calm environment to discuss embarrassing symptoms and ensure you are on the right clinical pathway for a formal diagnosis.