Canker Sores

Craig Kraffert, MD

Canker sores are painful, round or oval red ulcers in the mouth that typically have a yellowish or grayish center. Also referred to as aphthous stomatitis, canker sores are a common problem that affects at least 20 percent of the population at one time or another.

Major, Minor and Herpetiform

Canker sores are classified into three categories. The first type, minor, is most common and may begin during childhood. Minor canker sores develop on mucous membrane surfaces in the mouth: on the sidewalls of the mouth, the inner surfaces of the lips and under the tongue, which is most commonly affected. One to six sores smaller than a pencil eraser typically develop and last up to ten days.

The second type, major, may also begin during childhood. Major canker sores are larger and may affect any location in the mouth or even other places on the body including the stomach, intestines or rectum. These can also number from one to six but may last up to a month or longer and may sometimes leave scarring.

The third type, herpetiform ulceration, is rare but most severe and affects mostly women. These canker sores begin as ten to one hundred tiny ulcers that grow together to form what looks like a large sore. Herpetiform ulceration generally begins during young adulthood and most often develops on the undersurface of the tongue. This variant of canker sore can last up to a month or more.

Causes of Canker Sores

Although some researchers have suggested that viruses may play a role in the development of canker sores, there is no known scientifically proven cause. Certain disease processes include canker sores as part of their symptoms, but this observation has not helped explain how and why canker sores develop.

Approximately one out of three people with canker sores will have a family history of the condition. Some people tend to develop recurrent canker sores, and in these people, there may be certain circumstances that trigger the eruptions.

The most commonly reported triggers include trauma to the mucous membrane surfaces of the mouth, which often occurs during brushing of teeth, as well as iron or vitamin B12 deficiencies.

In some women, canker sores may be related to changes in the menstrual cycle and are occasionally triggered by the use of contraceptive pills. Once a trigger has been clearly identified, reasonable steps should be taken to minimize exposure to that trigger when possible.

Treatment of Canker Sores

Canker sores are not generally associated with underlying health problems and rarely, if ever, pose a significant health problem. The main concern of people with canker sores is that the sores tend to be extremely painful. Although canker sores resolve without treatment, many people desire treatment both to provide pain control and to make the sores heal faster.

Several over-the-counter and prescription remedies are available to treat the discomfort associated with canker sores. Products are also available that minimize the chance of developing recurrent sores.

For trauma-related sores, Rembrandt and Squiggle toothpastes have been proven to decrease the risk of forming canker sores that result from dental care. Zilactin oral gel is a safe and effective over-the-counter remedy that contains a topical anesthetic, which is applied topically to temporarily relieve the pain associated with cold sores. Used several times daily, this product can help make canker sores bearable. For people who have repeated bouts of canker sores that are not adequately relieved by Zilactin or similar products, prescription remedies are available.

Pain can be decreased and healing enhanced by the topical application of a prescription oral gel containing a medium to high strength cortisone anti-inflammatory. Cortisone-based products tend to work best when applied to the sores four times daily -- after meals and before bed.

Applying wet compresses consisting of a soft cloth soaked in a measured solution of tetracycline and water to the entire mouth surface for ten to fifteen minutes three times daily is another time-tested prescription remedy. This treatment is not available presently, however, due to a market shortage of tetracycline in the United States.

Canker sores are often a painful nuisance but only very rarely represent a serious medical problem. Fortunately, both over-the-counter and prescription remedies exist. While most canker sores can be treated with simple and safe over-the-counter measures, a physician should be consulted if there is any question about the correct diagnosis or if the canker sores become a significant ongoing or recurrent problem.