If you’ve been dealing with chronic diarrhea and searching for answers, microscopic colitis (MC) is one possibility worth discussing with your healthcare provider. This increasingly recognized condition shares symptoms with IBS-D (Irritable Bowel Syndrome with Diarrhea), yet it requires a different approach. Research suggests the incidence of microscopic colitis has more than doubled over the past decade, with current rates around 21 cases per 100,000 people per year.
Microscopic colitis has a strong association with certain medications like PPIs and NSAIDs, and the most common symptoms include chronic watery diarrhea, cramping, and bloating. Understanding this condition may help you have more informed conversations with your doctor about what’s really going on in your gut.
In this article, we’ll explore what microscopic colitis is, how it’s diagnosed, what factors may contribute to its development, and what the research says about the gut health connection.
What Is Microscopic Colitis?
Microscopic colitis involves inflammation in the colon (large intestine) and rectum. The term “microscopic” refers to the fact that this inflammation is invisible during a standard colonoscopy — it can only be detected when tissue samples are examined under a microscope.
Common Signs and Symptoms
People with microscopic colitis typically experience:
- Chronic, non-bloody, watery diarrhea (research indicates an average of 4 or more bowel movements per day)
- Abdominal cramping and discomfort
- Bloating
- Urgency
- Fatigue
- Unintentional weight loss (in some cases)
- Fecal incontinence (in more severe cases)
Two Types of Microscopic Colitis
There are two subtypes of microscopic colitis — collagenous colitis (CC) and lymphocytic colitis (LC). In collagenous colitis, there is a distinctive thickening of the collagen layer beneath the surface cells of the colon. Both types are diagnosed and managed similarly, and many experts believe they may represent different phases of the same disease process.
Who Does It Affect?
Microscopic colitis is most common in women over 40, though it can occur at any age. Studies suggest that 10-30% of patients investigated for chronic diarrhea will be diagnosed with microscopic colitis when biopsies are taken during colonoscopy.
How Is Microscopic Colitis Diagnosed?
Because the colon appears normal during a standard colonoscopy, microscopic colitis requires a tissue biopsy for diagnosis. This involves taking small samples of colon tissue during the colonoscopy procedure, which are then examined under a microscope by a pathologist.
It’s common for people with chronic diarrhea to receive an IBS-D diagnosis without a colonoscopy with biopsies. If your symptoms persist despite treatment, discussing a colonoscopy with biopsies with your healthcare provider may be worthwhile.
What Factors May Contribute to Microscopic Colitis?
The exact cause of microscopic colitis isn’t fully understood, but research has identified several factors that appear to play a role:
NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)
Research shows these common pain-relieving medications have a direct association with microscopic colitis. An estimated 30 million people use NSAIDs daily worldwide, making this a significant consideration.
Studies have observed that some patients with collagenous colitis saw symptoms and tissue changes improve when they stopped taking NSAIDs, and symptoms returned when the medications were reintroduced.
Research also indicates that NSAIDs can increase intestinal permeability within 24 hours of ingestion, potentially affecting gut barrier function.
Proton Pump Inhibitors (PPIs)
PPIs, frequently prescribed for acid reflux and heartburn, are associated with an increased risk of microscopic colitis in observational studies. Research suggests PPIs may promote changes in the gut environment that could affect intestinal health.
Bile Acid Malabsorption
Bile is a fluid that helps digest fats and carries waste products out of the body. When the intestine doesn’t completely reabsorb these bile acids, they can reach the colon and potentially contribute to diarrhea. One study found that 12 of 27 (44%) patients with collagenous colitis also had bile acid malabsorption.
Smoking
Cigarette smoking appears to be more prevalent among people with microscopic colitis compared to those without the condition. Research suggests smoking may increase the frequency of watery stools and decrease the likelihood of remission.
Autoimmune Connections
While no specific autoantibody has been confirmed, there is strong evidence suggesting an autoimmune component in both types of microscopic colitis. Studies reveal that approximately 30% of patients with microscopic colitis have other autoimmune-related conditions, including:
- Celiac disease (12.9%)
- Thyroid conditions (10.3%)
- Sjögren’s syndrome (3.4%)
- Rheumatoid arthritis
Among these associations, celiac disease appears to have the strongest connection. Research suggests patients with microscopic colitis have a 50 to 70-fold increased risk of also having celiac disease compared to the general population.
Genetic Factors
Family studies indicate that as many as 12% of patients with microscopic colitis have a family history of inflammatory bowel disease. Research has also found that microscopic colitis is strongly associated with the HLA-DR3-DQ2 genetic marker — the same marker prevalent in celiac disease. One study found this marker was more frequent in MC patients (43.8%) compared to controls (18.1%).
The Gut Health Connection
Research increasingly points to the relationship between gut health and various aspects of wellbeing. Here’s what studies suggest about microscopic colitis and gut function:
The Gut Barrier and Intestinal Permeability
The intestinal lining acts as a selective barrier, allowing nutrients to pass through while keeping potentially harmful substances out. When this barrier function is compromised — sometimes called “increased intestinal permeability” — it may contribute to various digestive and immune challenges.
Several of the factors associated with microscopic colitis also affect gut barrier function:
The NSAID-Gut Connection: Research demonstrates that NSAIDs can disrupt intestinal barrier function and increase intestinal permeability.
The PPI-Gut Connection: PPIs may promote changes in the gut environment, including affecting bacterial populations and intestinal transit time.
The Hormone-Gut Connection: Sex hormones like estrogen have been shown to have epithelial barrier-supporting properties. The hormonal shifts that occur during menopause may help explain why microscopic colitis is more common in women over 60.
The Infection-Gut Connection: Some research suggests a correlation between gut infections and the onset of microscopic colitis, with some patients showing improvement with certain antimicrobial approaches.
Short-Chain Fatty Acids and Gut Health
Emerging research highlights the importance of short-chain fatty acids (SCFAs), particularly butyrate, in maintaining intestinal health. Butyrate, produced by beneficial gut bacteria when they ferment dietary fiber, serves as the primary fuel source for colon cells and supports gut barrier integrity.
Studies show that people with inflammatory bowel conditions often have reduced levels of butyrate-producing bacteria compared to healthy individuals. This suggests that supporting a healthy gut microbiome may be one piece of the broader gut health picture.
Conventional Medical Approaches
The primary medical treatment for microscopic colitis is budesonide, a corticosteroid that targets the gut with minimal systemic absorption. Research shows budesonide is effective for inducing remission in 72-91% of patients.
However, studies also reveal an important limitation: symptom relapse occurs in 46-80% of patients within 6 months of stopping budesonide treatment. This high relapse rate has led many practitioners to consider maintenance therapy or complementary approaches.
Other medical approaches that may be considered include:
- Antidiarrheal medications for mild symptoms
- Bile acid binders for those with bile acid malabsorption
- Elimination of potentially triggering medications (NSAIDs, PPIs) when medically appropriate
- Smoking cessation support
Supporting Gut Health: A Complementary Focus
While working with your healthcare provider on appropriate medical management, many people also explore ways to support overall gut health. Research and clinical experience suggest several areas worth considering:
Dietary Considerations
Some people with microscopic colitis find that certain dietary approaches help manage symptoms. Working with a registered dietitian who understands digestive conditions can help identify any food sensitivities and ensure nutritional needs are met.
Supporting the Gut Microbiome
Given the research on butyrate and beneficial bacteria, supporting a healthy gut microbiome through fiber-rich foods (when tolerated) and potentially probiotics may be worth exploring with your healthcare provider.
Gut Barrier Support
Some individuals choose to support gut barrier function with supplements containing ingredients like L-glutamine or zinc carnosine, which have been studied for their effects on intestinal health. Learn more about L-glutamine and gut health.
Addressing Underlying Factors
Working with a knowledgeable healthcare provider to identify and address potential contributing factors — whether that’s medication use, celiac disease, or other autoimmune conditions — may be an important part of a comprehensive approach.
Frequently Asked Questions
How is microscopic colitis different from IBS-D?
While both conditions cause chronic diarrhea, microscopic colitis involves actual inflammation in the colon that can be seen under a microscope. IBS-D is considered a “functional” disorder without visible inflammation. The key difference in diagnosis is that MC requires a colonoscopy with biopsies, while IBS is typically diagnosed based on symptoms and ruling out other conditions.
Can microscopic colitis go away on its own?
Research suggests that some people with microscopic colitis may experience spontaneous remission, while others have a chronic or relapsing course. The disease trajectory varies significantly between individuals.
Is microscopic colitis an autoimmune disease?
While microscopic colitis shares characteristics with autoimmune conditions and is strongly associated with other autoimmune disorders, researchers are still working to fully understand its underlying mechanisms. The immune system clearly plays a role, but it’s not classified in the same category as conditions like rheumatoid arthritis or lupus.
Should I stop taking my NSAIDs or PPIs?
Never stop any prescribed medication without consulting your healthcare provider. If you’re concerned about a potential connection between your medications and digestive symptoms, discuss this with your doctor. They can help weigh the benefits and risks and explore alternatives if appropriate.
Does microscopic colitis increase the risk of colon cancer?
Unlike ulcerative colitis and Crohn’s disease, microscopic colitis does not appear to increase the risk of colorectal cancer.
What’s the connection between celiac disease and microscopic colitis?
Research shows a strong association between the two conditions, including shared genetic markers (HLA-DQ2). If you have microscopic colitis, your doctor may recommend testing for celiac disease, and vice versa.
Key Takeaways
- Microscopic colitis is increasingly recognized as a cause of chronic diarrhea, with incidence rates doubling over the past decade.
- Diagnosis requires a colonoscopy with biopsies — the inflammation is invisible to the naked eye but detectable under a microscope.
- Several factors are associated with MC, including NSAID and PPI use, smoking, bile acid malabsorption, and autoimmune conditions.
- Strong connections exist with celiac disease — patients with MC have a 50-70 fold increased risk of also having celiac disease.
- Conventional treatment with budesonide is effective, but relapse rates are high (46-80%) when treatment is stopped.
- Gut health may play an important role — research suggests connections between intestinal barrier function, the gut microbiome, and inflammatory conditions.
- A comprehensive approach working with your healthcare provider to address potential triggers, support gut health, and manage symptoms may offer the best path forward.
Want to Learn More About Gut Health?
If you’re interested in learning more about the connection between gut health and overall wellbeing, we’ve created resources to help you on your journey:
- Take our Leaky Gut Assessment
- Learn about the Autoimmune-Gut Connection
- Explore the Thyroid-Gut Connection
- Understand the Sjögren’s-Gut Connection
Medical Disclaimer
This content is for informational and educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition or before starting any new supplement, diet, or wellness program.
The statements made on this website have not been evaluated by the Food and Drug Administration. Our products and the information provided are not intended to diagnose, treat, cure, or prevent any disease.
Individual results may vary. Do not disregard professional medical advice or delay seeking it because of something you have read on this website.