Irritable Bowel Syndrome (IBS) & Canker Sores: What's the Connection?

Have you ever had those painful, annoying, small sores inside your mouth or under your tongue?

Those pesky things are canker sores. They aren't contagious, and they're not viral in origin. They usually look red, can be round or oval, and sometimes they have a whitish coating over them. Don't confuse them with cold sores, which occur outside the mouth, usually on the outer edges of the lips; those are caused by a strain of the herpes virus and are contagious. Typically canker sores come one at a time, although they may come in clusters, while cold sores come as multiple sores. Canker sores don't usually need medical treatment, and generally resolve themselves in 3 to 10 days.

Canker sores tend to occur most often in teenagers and in women. Irritable bowel syndrome, or IBS, is most common in the same group. So the question arises: are they connected, or is their co-occurrence just a coincidence?

Stress and food allergies, including problems with gluten, have been known to trigger canker sores in some patients. Both are also triggers for IBS. A poor diet -- one lacking sufficient fiber and containing too much acid, alcohol or sugar -- can be a trigger for canker sores and may also trigger IBS. A lack of iron and vitamin B12, which can be caused by inflammatory bowel disease, is considered a factor in canker sores, but patients need to remember that IBS is not the same as IBD; IBS is less serious and doesn't cause ulceration in the digestive system. An inadequate diet, caused by fear of the onset of a bout of IBS, however, may trigger canker sores. IBS flares, like IBD flares, can be triggered in some patients by acidic foods such as citrus fruits, pineapple and anything with vinegar. These same foods can trigger the formation of canker sores.

The most frequent causes of irritable bowel syndrome flares are stress, an unbalanced diet and lack of sleep. While none of these is the cause of canker sores, all of them can be factors in the development of canker sores.

The bottom line is that the cause of canker sores is uncertain and probably includes a number of different factors. The same type of sore can occur in different people for different reasons. If you have canker sores frequently and they don't heal themselves within a week, and if you have bouts of severe cramping and diarrhea at the same time, you should probably visit your doctor. These may be an indication of something more severe. Even if they aren't, your doctor can provide you with medication for both problems.