Colitis occurs when your colon, or large intestine, is inflamed.
Microscopic colitis is a type of colitis that’s best identified by looking at colon cells under a microscope. The main subtypes of microscopic colitis are collagenous colitis and lymphocytic colitis.
In collagenous colitis, a thick layer of collagen — a type of connective protein — forms within the colon tissue. Its symptoms can disappear and reappear.
The symptoms of collagenous colitis can come and go, and vary in severity.
The most common symptoms include:
- chronic watery diarrhea, which can appear and disappear over a period of weeks, months, or years
- abdominal pain
- abdominal cramps
Less common symptoms include:
Like many other gastrointestinal conditions, the exact cause of collagenous colitis is unknown. Research indicates that it likely has a genetic basis and could be related to autoimmune conditions.
Some possible causes of collagenous colitis include:
- genetic abnormalities
- autoimmune conditions such as rheumatoid arthritis, psoriasis, and Crohn’s disease
- certain bacteria or viruses
Collagenous colitis isn’t contagious. It can’t spread to other people.
Medications as triggers
Medications that may trigger microscopic colitis and collagenous colitis include:
- nonsteroidal anti-inflammatory drugs (NSAIDs)
- selective serotonin reuptake inhibitors (SSRIs), the most commonly prescribed class of antidepressants
- angiotensin-converting enzyme (ACE) inhibitors for high blood pressure
- angiotensin II receptor blockers (ARBs) for high blood pressure, heart disease, or kidney disease
Research is mixed on the effects of the following medications:
- statins for high cholesterol
- protein pump inhibitors (PPIs) and H2 receptor blockers, which are used to treat acid reflux and GERD
- oral medications for diabetes
Other studies indicate that these medications also trigger microscopic colitis and collagenous colitis.
According to a 2021 study, if these medications are associated with increased rates of microscopic colitis and collagenous colitis, it may be because they make diarrhea worse. A worsening case of diarrhea then prompts a doctor to make a diagnosis of colitis.
Collagenous colitis is more common among women than men. It’s also more common among people who are over 50 years old.
In addition, people who have celiac disease are more likely to have collagenous colitis.
Collagenous colitis may also be more common among people who currently smoke and people with a family history of the condition.
Researchers have noticed that the number of collagenous colitis cases is increasing. This may be because better detection is available and there’s increased awareness of the condition.
During the biopsy, a healthcare professional removes several small pieces of tissue from your colon. Then the tissues are examined under a microscope.
The common diagnostic process includes:
- a medical history
- colonoscopy with a biopsy
- lab tests, such as blood and stool tests
- imaging tests, such as CT scans, MRIs, or X-rays
In some cases, collagenous colitis disappears on its own. However, some people need treatment.
Your treatment plan will depend on the severity of your symptoms.
Diet and lifestyle changes
Your doctor may recommend diet and lifestyle changes to help treat this condition. These changes are usually the first part of any treatment plan.
Common diet changes include:
- eating a reduced fat diet
- opting for a gluten-free diet
- drinking more fluids to prevent dehydration from diarrhea
- switching to a milk-free diet
- avoiding food with artificial sweeteners
- eliminating caffeine and lactose
Common lifestyle changes include:
- quitting smoking, if you smoke
- maintaining a moderate weight
- maintaining a healthy blood pressure
- exercising regularly
Your doctor will review the medications you currently take and make suggestions about either continuing or stopping them.
In 2016, the American Gastroenterological Association (AGA) released its guidelines on microscopic colitis. The AGA recommends starting with budesonide, a type of corticosteroid, before considering other medications.
Other medications your doctor may recommend to help treat the symptoms of collagenous colitis include:
- antidiarrheal medications
- intestinal anti-inflammatory medications, such as mesalamine (Apriso, Asacaol HD, Pentasa) or sulfasalazine (Azulfidine)
- medications that block bile acids, such as cholestyramine (Prevalite)
The supplement psyllium may be recommended, too. Immunomodulators or anti-TNF (tumor necrosis factor) therapies may be used in extreme cases.
The Food and Drug Administration (FDA) hasn’t approved any medications for microscopic colitis or collagenous colitis. However, medications such as mesalamine and sulfasalazine are FDA approved for the treatment of ulcerative colitis.
If a doctor prescribes medications such as these for collagenous colitis, it’s considered an example of off-label drug use.
OFF-LABEL DRUG USE
Off-label drug use means a drug that’s approved by the FDA for one purpose is used for a different purpose that hasn’t yet been approved.
However, a doctor can still use the drug for that purpose. This is because the FDA regulates the testing and approval of drugs, but not how doctors use drugs to treat their patients. So your doctor can prescribe a drug however they think is best for your care.
Your doctor may recommend surgery if diet and medication changes don’t help. Surgery is usually reserved for extreme cases. It’s not a typical treatment for collagenous colitis.
The most common types of surgery for collagenous colitis include:
Collagenous colitis doesn’t cause blood in your stool, increase your risk of colon cancer, or have any effect on life expectancy. Symptoms may affect a person’s quality of life, but they’re not life threatening and won’t typically require emergency medical care.
However, it’s worth seeing a doctor if you have chronic watery diarrhea in combination with any of the common risk factors for collagenous colitis.
You’ll also want to see a doctor if you’re diagnosed with collagenous colitis and your recommended treatment plan doesn’t help reduce your symptoms.
Collagenous colitis can come and go, and relapses are common. You may need to try several treatments to find relief from the symptoms.
The time it takes to recover can vary. Some people may have symptoms for weeks, months, or years.