Melanosis coli is a harmless condition in which the lining of the colon and rectum, which is usually pink in color, turns a shade of black or brown. Experts think the lining of the colon darkens — resulting in melanosis coli — when the cells in the colon are destroyed and an excess of the pigment lipofuscin is produced. The discoloration can vary from one person to the next. It may be slight or severe, and affect a small or large portion of the colon.
The biggest risk factor for melanosis coli is frequent laxative use. Laxatives are often used by people who are constipated.
Anthraquinone-based laxatives are most likely to cause melanosis coli because they’re most likely to damage and destroy the cells that line the colon. These laxatives are products that stimulate the colon to pass stool more quickly. They contain ingredients like senna, aloe, and rhubarb. Learn the difference between popular laxatives and stool softeners.
Research published in the Indonesian Journal of Gastroenterology Hepatology and Digestive Endoscopy suggests that 70 percent of people who frequently take anthraquinone laxatives will develop melanosis coli, often within just a few months of use.
More women are diagnosed with melanosis coli than men. That may be because more women experience constipation than men, which may in turn lead to more laxative use. In fact, research published in the American Family Physician notes that women are three times more likely than men to be constipated.
Melanosis coli produces no symptoms, nor does it cause any bowel or digestive issues. A person who has this discoloration may never know it.
Because melanosis coli produces no symptoms, most people who have it find out by chance. Procedures that explore the colon, such as colonoscopies and sigmoidoscopies, can uncover the condition. But in general, it’s an accidental finding.
There are many reasons why you may undergo a test like a colonoscopy. A colonoscopy may be ordered to screen for colon cancer, or because of abnormal rectal bleeding, abdominal problems, chronic diarrhea, or constipation.
Experts note that melanosis coli is a “benign” finding, which means it doesn’t pose any health risks. However, there has been some debate about a possible connection between melanosis coli and colon cancer. But the research thus far has been inconclusive.
While one recent study published in the Polish medical journal Przeglad Gastroenterologiczny found that 11.9 percent of colon cancer patients also had melanosis coli, the researchers note the incidence was too small to establish a link between the two conditions.
On the flip side, some tumors and polyps are actually easier for doctors to detect in people with melanosis coli. That’s because they stand out against the dark backdrop of the pigmented colon lining.
There is no treatment for melanosis coli. According to research published in the British Medical Journal, it’s generally reversible within 6 to 12 months after a person stops using anthraquinone-containing laxatives.
Key to preventing melanosis coli is preventing constipation and the subsequent use of laxatives. The American Academy of Family Physicians (AAFP) notes that having anywhere from three bowel movements a day to three a week is considered normal. But when you move your bowels less frequently than three times a week, chances are you’re experiencing constipation.
When you’re constipated, you may not feel like you’re emptying your bowels completely. You may also feel bloated and gassy, and your stools may be hard.
To prevent constipation, the AAFP recommends the following strategies:
- Eat more fiber-rich foods. These include fruits, vegetables, and whole grains. Fiber adds bulk to your stool and helps it pass more easily through your colon. Fiber-containing supplements may also help. Aim for 25 to 35 grams of fiber per day.
- Drink more fluids. Fluids will help fiber work better and allow your stools to pass through the colon more easily.
- Don’t resist the urge to have a bowel movement. Listen to your body and use the bathroom when necessary. Resting your feet on footstool while trying to move your bowels may also help.
See your doctor if these measures don’t help, if you notice blood in your stool, or you’re 50 or over and need to schedule a colonoscopy.
Many people with melanosis coli never know they have it until a test performed for another reason leads to a diagnosis. It causes no symptoms or health risks.
Regardless, it’s important to tell your doctor about prolonged constipation and laxative use. Chronic constipation can lead to other health conditions like hemorrhoids or impacted feces. And overusing laxatives can actually make constipation worse.