Other Inflammatory Bowel Diseases

Crohn’s disease and ulcerative colitis are the most common forms of inflammatory bowel disease. However, there are several other diseases that cause inflammation of the large intestine (colon). These diseases are rarer and they can be hard to diagnose.¹

Microscopic colitis (collagenous colitis and lymphocytic colitis)

Microscopic colitis is an inflammation of the large intestine that can only be seen under a microscope.² There are 2 forms of microscopic colitis: collagenous colitis and lymphocytic colitis. Both have the same symptoms and treatments. In both types, the number of lymphocytes (a type of white blood cell) goes up. The difference between them is whether the walls of the large intestine change. In people with collagenous colitis, the layer of collagen gets thicker. In people with lymphocytic colitis, the thickness of the walls stays normal. Lymphocytic colitis is more common than collagenous colitis.³

What are the risk factors for microscopic colitis?
Microscopic colitis is most likely to affect older adults. The average age at diagnosis is 65 years.³ However, people can have microscopic colitis at any age.⁴ Women are more likely to be affected than men.³ Smokers are 3.8 to 5.4 times more likely than non-smokers to develop microscopic colitis.⁵ They also develop this type of colitis at a younger age.

One study showed that 28% of people with microscopic colitis had other autoimmune diseases.⁶ Autoimmune disease happens when your body’s immune system attacks your body’s own cells.² In this study, celiac disease was the most common overlapping autoimmune disease.⁶

What are the symptoms of microscopic colitis?
The main symptom of microscopic colitis is frequent, watery diarrhea.⁴ Nearly everyone with microscopic colitis has diarrhea.⁶ The diarrhea frequently occurs at nighttime. About 8% of people have fecal incontinence, which is when you cannot control your bowel movements. Besides diarrhea, common symptoms are abdominal pain and weight loss.

How is microscopic colitis diagnosed?
The only way to diagnose microscopic colitis is to examine tissue samples from the large intestine.⁴ This procedure is called a biopsy. Additional tests may be done to rule out other types of inflammatory bowel disease. (NIDDK, Microscopic Colitis) These tests may include blood tests, stool samples, colonoscopy, or imaging tests.

How is microscopic colitis treated?
The first step is usually to stop medications that might contribute to colitis, such as NSAIDs or proton pump inhibitors.⁵ If you smoke, quitting might help.⁵ People with mild colitis may get better with no treatment or just taking an anti-diarrheal medication.⁶

Budesonide is a steroid medication that is often used to treat people who have more severe disease.^2,5 It helps about 80% of people with microscopic colitis.⁵

Other medications may be used with or instead of budesonide. These include:^2,5

• Anti-inflammatory medications
• Cholestyramine, a medication that stops your liver from making bile
• Antibiotics
• Medications that weaken the immune system (immunomodulators)
• Biologic medications

Surgery is used rarely to treat microscopic colitis.²

Diversion colitis

Diversion colitis is an inflammation in the part of the large intestine that is left after “fecal diversion.”¹ Fecal diversion is a surgical procedure sometimes needed to treat a disease of the large intestine.

Normally, food is digested and absorbed by the time it reaches the end of the small intestine. The leftover residue that enters the large intestine (colon) is mainly liquid waste material.⁷ If your digestive tract is working normally, the waste becomes more solid (feces) as it passes through the large intestine. The waste is held in the rectum and eliminated through the anus.

Fecal diversion is done to re-route the waste, in order to treat some diseases in the large intestine.⁷ The healthy end of the large intestine—or in some cases, the small intestine—is attached to a surgical opening in the skin. The waste is eliminated through the small opening, called a colostomy. (If the end of the small intestine is attached to the skin, the opening is called a ileostomy.) The opening has no sphincter muscles. This means that you cannot control the flow of waste out of this opening. Instead, you wear a small pouch, called an ostomy bag, to collect the waste.

Diversion colitis develops in the part of the intestine that is no longer in use. Scientists do not know exactly why this happens. One factor is that the helpful bacteria that live in the colon do not get the “food” they need.¹ These bacteria usually live on the undigested starches and fiber in normal waste. The parts they consume are called short-chain fatty acids. When the waste no longer passes through that part of the colon, some of these bacteria start to die.

What are the symptoms of diversion colitis?
Symptoms include bloody or mucus discharge, abdominal pain, or fever.¹ Some people feel like they need to have a bowel movement, even though there is no waste to eliminate. Although most people have diversion colitis after fecal diversion, less than half of people have symptoms.¹

How is diversion colitis diagnosed?
Diversion colitis is diagnosed with colonoscopy. Colonoscopy is a procedure that your doctor performs using a long, thin tube with a very small camera and light. The camera lets your doctor see inside your digestive tract. Your doctor will look for signs of diversion colitis. Signs include redness, abnormally growing connective tissue, ulcers, bleeding, erosion, swelling, polyps, and narrowing within the colon.¹

How is diversion colitis treated?
The best treatment for diversion colitis is to reconnect the large intestine so that waste can flow through normally.¹ If this is not possible, enema treatments may be helpful. An enema is a way of administering a liquid medication by injecting the solution into the large intestine via the rectum. Diversion colitis is treated with enema solutions that have short-chain fatty acids or fiber.¹

Behçet's disease

Behçet's disease is a rare autoimmune disease that causes inflammation of the blood vessels. This disorder affects various different parts of the body.¹

Behçet's disease is most common among people living along the ancient Silk Route, which ran from Turkey to China and Japan.¹ In the West, it is more likely to affect people who descend from immigrants from this region.

What are the symptoms of Behçet's disease?
The main symptoms of Behçet's disease are mouth ulcers, genital ulcers, and eye inflammation.¹ If the digestive tract is affected, ulcers are most likely to appear at the end of the small intestine (ileum) and start of the large intestine (cecum). For this reason, it is easy to confuse Behçet's disease with Crohn’s disease.¹

How is Behçet's disease diagnosed?
There are no tests for Behçet's disease. The diagnosis is based on symptoms.⁸ The symptoms come and go, so it can take a long time to be diagnosed.

How is Behçet's disease treated?
The goal of treating Behçet's disease is to control the symptoms. Gels, creams, or ointments are applied right to the affected areas. These tend to have steroids, anti-inflammatory medications, or pain relievers.8 Some people with Behçet's disease take a medication called colchicine (Colcrys).¹ It is meant to treat gout, but it helps treat symptoms of Behçet's disease. It does not reduce inflammation in the large intestine.¹

Biologic medications and corticosteroids reduce inflammation throughout the body. Eye drops, mouth rinses, and other medications may be needed to relieve symptoms in various parts of the body.

Indeterminate colitis

The term “indeterminate colitis” is used when it is not possible to tell whether a person has ulcerative colitis or Crohn’s disease.⁹ This label is controversial because it is not well defined.⁹ Health care providers debate about when it should be used. They disagree about which procedures should be done to come up with a more specific diagnosis. Some people with indeterminate colitis are eventually given a more specific diagnosis.⁹