Ulcers in the colon are usually due to a condition like inflammatory bowel disease or an infection. But some medications or procedures can also cause colon ulcers.

A colon ulcer is an open sore that develops in your large intestine (colon).

Colon ulcers can have many causes. Read on to learn about common causes of colon ulcers and how doctors usually detect and treat them.

Symptoms of colon ulcers

Here are some of the possible symptoms of colon ulcers to watch out for:

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Ulcerative colitis(UC) happens when your colon or rectum becomes inflamed. UC is part of a category of conditions known as inflammatory bowel disease (IBD).

Like other types of IBD, UC can be passed down through your genes or result from an autoimmune disorder where your body attacks its own healthy tissues. It’s not usually due to an infection or other source outside your body.

Crohn‘s disease is another type of IBD that mostly happens in the small intestine and colon, resulting in ulcers.

Like UC, it’s often passed down in families and may result from an autoimmune disorder. A 2019 literature review suggests that Crohn‘s disease may result from lifestyle or environmental triggers, such as:

  • smoking (if you smoke)
  • stress
  • depression
  • not getting enough sleep

What can cause aphthous ulcers in your colon?

Aphthous ulcers are tiny lesions that appear as white spots about 1–5 millimeters in diameter. Several of these spots can join together to form larger lesions.

They most notably form on the mucus lining in your mouth, where they’re known as canker sores. But they can also form on the mucus lining of your colon wall in the early stages of Crohn’s disease.

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Colon cancer happens when cancerous cells replace healthy cells and spread throughout colon tissues.

Ulcers may develop as cancerous cells irritate the colon tissue and grow farther out into the colon from the colon lining.

Cancers of the colon and rectum are the third most common cancer types in the United States. They result in many of the same symptoms as IBD.

C. diff is a type of bacteria. Most people have a certain amount of C. diff in their intestines. However, excessive growth of these bacteria in your stomach can cause colon ulcers.

Excessive C. diff growth may be due to the following reasons:

  • taking antibiotics
  • being age 65 or older
  • getting surgery on your gastrointestinal tract
  • having a compromised immune system
  • long-term kidney or liver conditions

Some parasites can get into your colon and cause inflammation. This is known as parasitic colitis.

Colon ulcers that result from parasites are often due to eating food or drinking water that hasn’t been properly cleaned or sanitized. Colon ulcers from parasites can also increase your risk of developing IBD.

Over 3 billion people worldwide carry some form of intestinal parasite in their bodies, but certain parasites grow excessively in the intestine and cause colon ulcers.

Diverticulitis happens when pouches called diverticula form in your colon and become inflamed or infected. If food particles get stuck in these pouches, they can increase pressure in the wall of your colon, causing erosion. Though not as deep as an ulcer, erosion can still lead to complications.

Most cases of diverticulitis are temporary and go away on their own. But if not treated, diverticulitis can develop into abdominal abscesses, fistulas, or perforations, which can be life threatening.

Surgeries to treat conditions like Crohn’s disease and colon cancer may result in irritation to colon tissue and cause colon ulcers to develop.

A 2020 study found that over half of people with Crohn’s disease who underwent a surgery called ileocolic resection had ulcers develop in their colon afterward. The two parts connected after surgery form anastomosis. The ulcers developing there are called anastomotic ulcers.

Though rare, long-term use of certain nonsteroidal anti-inflammatory drugs (NSAIDs) may also cause colon ulcers. NSAIDs are more likely to affect organs early in the digestive process, like your stomach or small intestine. Still, there are reports of colonic ulcers from long-term NSAID use in high doses.

Other symptoms of NSAIDs’ effects on the colon include anemia, bowel obstruction, and bloody diarrhea.

Stopping NSAID use will usually help the ulcers to heal.

Some diagnostic tests used to detect a colon ulcer include:

  • blood tests to find signs of ulcers or their causes, such as anemia
  • stool tests to examine your poop for infections or inflammation
  • endoscopy of the colon and rectum to look for symptoms of IBD or cancerous tumors
  • CT or MRI scans to look at detailed images of the colon

The treatment for a colon ulcer depends on the cause. Some possible treatments may include:

  • changes in your diet to help reduce inflammation
  • medications, such as biologics, for inflammation
  • antibiotics to treat bacterial infections
  • hospitalization if you lose lots of fluids or nutrients
  • surgery to remove colon cancer or parts of your colon if needed

How long does it take for ulcers in the colon to heal?

The healing time for a colon ulcer will depend on its size and cause. For example, ulcers caused by UC take about 2 months to heal when treated, while ulcers caused by Crohn’s disease may take twice as long.

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Are ulcers in the colon cancerous?

Most colon ulcers are not cancerous. However, colon cancer may cause ulcers. Having UC or Crohn’s disease may also increase your risk of colon cancer.

What is the difference between ulcers and ulcerative colitis?

Ulcers are temporary and result from inflamed tissue in your colon, which may occur because of many different reasons. They typically go away on their own or with treatment.

UC is a chronic condition that causes colon inflammation due to factors like genetics, environment, and the presence of autoimmune disorders. Treatment is available, but there isn’t a cure.

What is the difference between colitis and ulcerative colitis?

Colitis happens when your colon is inflamed. Colitis usually goes away when the source of the inflammation, such as an infection, is treated.

But UC is chronic and usually results from a problem with your immune system.

There are many possible causes for a colon ulcer, including infectious bacteria or conditions that result from autoimmune disorders. Medications or surgery can also cause ulcers to form in your colon.

Contact a healthcare professional if you experience symptoms of a colon ulcer for a few days or more so that you can understand the cause and possible treatments available.