Recurrent canker sores are one of the most common inflammatory conditions of the mouth, afflicting about 20 percent of the general population. The medical terms for canker sores are aphthous stomatitis or aphthae.
Canker sores begin as small oval or round reddish swellings, usually on the movable parts of the mouth such as the tongue and the inside linings of the lips an cheeks. These swellings usually rupture within a day, are covered by a thin white or yellow membrane, and become edged by a red halo. The size of the sores varies from being an eighth of an inch wide in minor infections to an inch and a quarter wide in more severe cases. Fever is rare and there rarely is an association of canker sores with other diseases. Usually a person will only experience a single or a few canker sores at a time. These sores generally heal within 2 weeks. Severe forms of the sores may leave scars.
Most people experience their first bout with canker sores when they are between the ages of 10 and 20 although children as young as 2 years of age may develop the condition. The frequency of canker sore recurrences varies considerably. Some people may only experience one or two episodes a year, whereas others may have a continuous series of canker sores. Most people experience tingling or pain in the area of the mouth where canker sores later develop.
What Causes Canker Sores?
It is not known what causes canker sores in all patients although more than one cause is likely even for individual patients. Attempts to find bacteria or viruses linked with the disease have not proven fruitful although an allergy to a type of bacteria commonly found in the mouth may cause some people to develop canker sores. The sores might also be an allergic reaction to certain foods eaten. In addition, there is research that suggests canker sores may be caused by a faulty immune system that uses the body's defenses against disease to attack and destroy the normal cells of the mouth or tongue.
British studies indicate that canker sores in about 20 percent of all patients are partially caused by nutritional deficiencies, especially a lack of vitamin B12, folic acid and iron. Similar studies performed in the United States, however, have not confirmed these findings. In a small percentage of patients canker sores occur in conjunction with gastrointestinal problems, such as an inability to digest certain cereals, and thus appear to be part of a generalized disorder of the digestive tract.
Female sex hormones apparently play a role in causing canker sores. Many women only have bouts of canker sores during certain phases of their menstrual cycles. The majority of women, in addition, experience improvement or remission of their canker sores during pregnancy. In clinical studies, researchers have also used hormone therapy to successfully treat some women.
Both emotional stress and injury to the mouth, such as scratching by abrasive foods or a stray toothbrush bristle, can trigger outbreaks of canker sores although these factors probably do not cause the disorder.
Who Is Susceptible?
Women are more likely than men to have recurrent canker sores and professionals are more likely to have the disorder than nonprofessionals. Genetic studies indicate that susceptibility to recurrent outbreaks of canker sores is inherited in some patients, which partially explains the frequent tendency of the disorder to be shared by family members.
Most doctors recommend that patients who have continual or frequently recurring bouts of canker sores undergo blood and allergy tests to determine if their sores are caused by a nutritional deficiency, an allergy, or some other correctable cause. Vitamin and other nutrient supplements often prevent recurrences or reduce the severity of canker sores in patients with a nutritional deficiency. Avoidance of foods a patient is allergic to can also reduce the frequency of canker sore recurrences.
There are a number of treatments that reduce the pain and duration of canker sores for patients whose outbreaks cannot be prevented. These treatments include numbing preparations such as xylocaine that are applied on the sores when a patient has only a few, and anti-inflammatory steroid mouthwashes or gels for patients with several sores. Mouthwashes containing the antibiotic tetracycline may reduce the unpleasant symptoms of canker sores and speed healing by preventing complicating bacterial infections in the sores. Clinical studies at the National Institute of Dental Research have shown that rinsing the mouth with tetracycline several times a day usually relieves pain in 24 hours and allows complete healing in 5 to 7 days. The U.S. Food and Drug Administration warns, however, that tetracyclines administered to pregnant women and young children can permanently stain teeth. Steroid and tetracycline treatments both require a prescription and care of a physician or dentist.
Patients with severe recurrent canker sores may need to take steroid or other immuno-suppressant drugs orally. These potent drugs may cause many undesirable side effects, however, and should be used only under the close supervision of a physician or dentist.
Another option is to have your dentist treat these sores with a laser. This laser should be a red diode type laser.
What the Patient Can Do?
Patients with outbreaks of canker sores should avoid abrasive foods such as potato chips that can stick in the cheek or gum and further aggravate the sores. Care should be taken when brushing the teeth so as not to stab the sores with a toothbrush bristle. Acid and spicy foods should also be avoided. Canker sores are not contagious so patients do not have to worry about transmitting the disease to people with whom they are in contact.
Research on Canker Sores:
Much of the research on canker sores centers on trying to identify malfunctions in patients' immune systems that render them susceptible to recurrent bouts of canker sores. By analyzing the blood of patients with and without recurrent canker sores, scientists have discovered several differences in immune function between the two patient groups. Whether these differences in immune function cause canker sores is not known yet.
Research on canker sores also includes developing and testing new drugs designed to treat patients with canker sores. Most of the drugs being developed alter the patient's immune function. Although some of these compounds appear to effectively treat some patients, the data is still inconclusive. Until these drugs are definitively shown to be both safe and effective, they will not be available for general use.