Digestive Health Irritable Bowel Syndrome IBS With Diarrhea IBS and Microscopic Colitis By Barbara Bolen, PhD twitter Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome. Learn about our editorial process Barbara Bolen, PhD Medically reviewed by Medically reviewed by Robert Burakoff, MD, MPH on September 28, 2020 linkedin Robert Burakoff, MD, MPH, is board-certified in gastroentrology. He is the vice chair for ambulatory services for the department of medicine at Weill Cornell Medical College in New York. Learn about our Medical Review Board Robert Burakoff, MD, MPH on September 28, 2020 Print Table of Contents View All Overview Symptoms Diagnosis Causes Treatment IBS vs. Microscopic Colitis Both IBS and microscopic colitis share the symptom of chronic diarrhea. Thus it is understandable to wonder if they are related. The treatment for the two conditions is very different - therefore you will want to be assured that you have the right diagnosis. In this overview, we will look at what microscopic colitis is and how it differs from IBS. Jose Luis Pelaez Inc / Blend Images / Getty Images Overview Microscopic colitis is a condition in which a person experiences chronic watery, but not bloody, diarrhea. The disease is more likely to affect women than men and your risk goes up as you age, with the highest incidence seen in people who are in their 60s or 70s. There are two types of microscopic colitis: Collagenous colitis and lymphocytic colitis. They differ in terms of the way they look but are possibly just two different stages of the same disorder. Regardless of type, the two disorders are diagnosed and treated the same way. In lymphocytic colitis, there is an increased number of white blood cells present in the tissue of the lining of the colon. In collagenous colitis, a thick layer of collagen is seen in the tissue. Symptoms In addition to the symptom of chronic watery diarrhea, microscopic colitis may also result in: Abdominal pain and/or crampsNauseaFecal incontinenceWeight loss Symptoms may be intermittent and at times, the disease can resolve on its own without any medical treatment. Diagnosis Similar to IBS, with microscopic colitis, there is no sign of the disease seen during a colonoscopy. Where the two disorders differ is that microscopic colitis will show up when a sample of colonic tissue is looked at under a microscope. In addition to the colonoscopy with biopsy, other tests will be given to rule out other diseases. Blood work, with possible endoscopy, will be recommended to rule out celiac disease. A stool test may be recommended to identify any pathogens that might be causing diarrhea. Causes No one knows for sure what causes microscopic colitis. Risk factors include: Bile acid diarrheaCeliac diseaseH2 blockersNon-steroidal anti-inflammatory drugs (NSAIDs)PolyarthritisProton pump inhibitors (PPIs)SmokingSelective serotonin reuptake inhibitors (SSRIs)Thyroid problems Treatments As you will see, the treatment options for microscopic colitis are very different than the treatment options for IBS. The first step may be to have the patient stop smoking or discontinue any medications that are suspected as contributing to the disease. Medications may be prescribed. At its worst, microscopic colitis may be addressed through ileostomy surgery. IBS vs. Microscopic Colitis Having learned about microscopic colitis, you still may be wondering if you have the correct diagnosis. A recent meta-analysis looked at the results of numerous studies on the topic. Combining data from these studies, the authors concluded that although approximately one-third of patients who have microscopic colitis report IBS symptoms, this percentage did not differ from people who do not have microscopic colitis. The overlap between IBS and microscopic colitis differed depending on study design. In case-control studies, microscopic colitis was seen more often in people who have IBS than those who had no symptoms. But in studies that looked at evidence across large groups, people who have IBS are no more likely to have microscopic colitis than people who have diarrhea but who don't have IBS. Based on this meta-analysis, the authors recommend that unless you are at higher risk for microscopic colitis (based on the above risk factors) or any red-flag digestive symptoms, there is no need for a person with IBS to undergo a colonoscopy to rule out microscopic colitis. Of course, if your IBS symptoms change, you should inform your doctor, with this expectation that further testing may be warranted to obtain an accurate diagnosis. Why are the symptoms of IBS and microscopic colitis similar, although they are different diseases? Certainly, low-level inflammation has been associated with IBS. The answer may be that they lie on a continuum. Hopefully, continued research will help to make the issue much clearer. Was this page helpful? Thanks for your feedback! One of the most challenging aspects of having IBS is trying to figure out what's safe to eat. Our recipe guide makes it easier. Sign up and get yours now! Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. "Microscopic Colitis" Mayo Clinic website Accessed October 16, 2015. Kamp, E., Kane, J. & Ford, A. "Irritable Bowel Syndrome and Microscopic Colitis: a Systematic Review and Meta-analysis" Clinical Gastroenterology and Hepatology Articles in Press Published Online October 7, 2015. Park, T., Cave, D. & Marshall, C. "Microscopic colitis: A review of etiology, treatment and refractory disease" World Journal of Gastroenterology 2015 21:8804–8810.