Collagenous Colitis

Collagenous colitis is an inflammatory bowel disease that causes chronic, watery diarrhea. It gets its name from the way it affects the collagen in your colon lining. Collagen is a protein that your body uses to build connective tissues. This is what the middle layer of your colon lining is made of. In collagenous colitis, this layer of collagen is abnormally swollen and thickened. This is only visible under a microscope.

Inflammatory bowel diseases are conditions that involve ongoing irritation inside your intestines. Symptoms may come and go and get better or worse, but they keep coming back. Collagenous colitis belongs to a subtype of inflammatory bowel disease called microscopic colitis. It won’t show up during a routine colonoscopy. To diagnose it, your provider will need to take biopsies and send them to a lab.

Symptoms of collagenous colitis

The primary symptom of collagenous colitis is chronic, watery diarrhea. (It’s not bloody, like it can be with other types of colitis.) You may have to go many times in a day and may find it hard to hold in. You may also have abdominal pain or cramps with it. If it’s severe, you may get dehydrated or lose weight.

Some people with collagenous colitis also have symptoms of inflammation in other parts of their body.

These may include:

• Joint pain and stiffness
• Skin rashes or sores
• Extreme tiredness (fatigue)
• Stomach pain or digestive problems

Collagenous colitis causes

Researchers aren’t sure what causes collagenous colitis. Some think it might be an unidentified infection. Others believe it’s a type of autoimmune disease. This means your immune system produces inflammation by mistake. It acts like something is infecting or injuring your colon, even though it isn’t.

Researchers have suggested it may be a reaction to:

• Infections that damage your colon lining, like C. diff and Yersinia
• Drugs that can injure your colon lining over time, like NSAIDs
• Allergens in your colon, like pollen or foods

Risk factors

You may be more likely to be diagnosed with collagenous colitis if you:

• Are female (the female-to-male ratio is 3:1)
• Have a biological family member with inflammatory bowel disease
• Have other gastrointestinal diseases, like bile acid malabsorption (BAM), celiac disease or IBS
• Have a whole-body (systemic) autoimmune disease, like rheumatoid arthritis or scleroderma
• Smoke (smoking may increase your risk by as much as five times)
• Take medications that can reduce your bowel immunity, like NSAIDs, PPIs or SSRIs

Complications of collagenous colitis

The inflammation in collagenous colitis isn’t usually severe. So, it rarely leads to the kinds of complications that severe colitis can. The most likely complications are dehydration and weight loss from frequent diarrhea. Some people do develop other symptoms. But most improve with treatment.

How doctors diagnose collagenous colitis

To diagnose collagenous colitis, your doctor must take several tissue samples from your colon lining. They’ll do this during a colonoscopy. Then, a pathologist will examine the samples under a microscope. They’ll recognize collagenous colitis if they see thickened collagen in one of your tissue samples.

Getting the right diagnosis can be a process. Many conditions can cause chronic diarrhea. And if you have more than one, their symptoms can complicate the picture. The wait can be frustrating, but stick with it. Your provider must suspect microscopic colitis before they can test for it.

What is the treatment for collagenous colitis?

Treatment for collagenous colitis may include:

• Dietary changes: Eliminating foods and drinks that trigger your diarrhea may help relieve it. These can vary. Common triggers include dairy, gluten, sweets, alcohol and caffeine.
• Antidiarrheal medications: For some people, over-the-counter (OTC) medications like bismuth subsalicylate or psyllium may relieve diarrhea. Your provider may also prescribe medications, like loperamide.
• Anti-inflammatory drugs: A short course of corticosteroids (usually budesonide) helps to bring down the inflammation. If that doesn’t work, your provider might prescribe biologic DMARDs.

What is the outlook for collagenous colitis?

With the right diagnosis and treatment, most people find relief from the symptoms of collagenous colitis. For some, the disease may go into remission, and all signs and symptoms may appear to go away. For others, it may reappear occasionally. You may need to take medications on and off for life.