They’re often surrounded by a ring of red, inflamed tissue. They can also be irregular in shape, like long, ragged marks. You may hear these called rake ulcers or bear claw ulcers.
While they don’t always cause long-term problems, an erosion or ulcer on the surface can tunnel deeper into your colon and turn into a fistula. That’s when tissue is inflamed through the whole wall of your bowel, creating a tunnel to other nearby organs. You’ll need surgery to repair a fistula.
What Causes Colon Ulcers?
Colon ulcers have many causes. Where the ulcers are located in your colon may help diagnose the cause.
Crohn’s disease and ulcerative colitis (UC). Both Crohn’s and UC are types of inflammatory bowel disease (IBD), an inflammation of your colon. These diseases can cause erosions or ulcers in your colon tissue. In Crohn’s, ulcers affect patchy areas of the colon. They can appear in any part of your intestine. UC inflammation affects only the inner lining of your large intestine. It never causes ulcers in your small intestine.
Colon ulcers are often the first sign of Crohn’s. Ulcers caused by Crohn’s disease often crop up on the side of your colon near the mesentery, the tissue that holds your intestines to the inner wall of your abdomen.
After surgery. Erosions and ulcers are a rare possible complication of gastric band surgery to treat obesity. The band can slip and travel to your colon, where it causes an erosion. Your doctor can diagnose this with an image test like a colonoscopy, which uses a camera on the end of a long, flexible tube to examine your colon.
Diverticulitis. As many as 60% of older adults develop diverticulitis, an inflammation of sac-like bulges in your colon wall. If digested food gets stuck in the sac, it can cause pressure to build up and can lead to an erosion.
Infections. Microscopic bugs can get into your gut and cause an infection that leads to colon erosions. Ascariasis is a parasite infection that can cause multiple colon erosions. The parasite’s tiny eggs may show up in your stool when it’s tested in the lab.
Another type of gut infection is C. difficile, or C. diff. It results from bacteria that infect your colon. A C. diff infection can cause stomachaches and diarrhea. If you don’t treat it, the germs can cause severe inflammation and erosions in your colon.
You can also get colon erosions from infection with cytomegalovirus (CMV).
Terminal ileitis (TI). Inflammation in the terminal part of your ileum, or small intestine, may result from Crohn’s disease, but this painful condition has other causes, too. TI can lead to ulcers or erosions in your large intestine that your doctor can spot during a colonoscopy.
Medications. Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used pain medications for arthritis. But NSAIDs can cause small ulcers in your colon. Doctors call this NSAID colitis. Symptoms are upset stomach, diarrhea, or anemia. If you use NSAIDs daily, you may be at risk for colon erosions, but they’ll heal once you switch to a different medicine.