Canker sores, also known as aphtous ulcers, are small lesions that develop in the mouth. Unlike cold sores, canker sores do not occur on the surface of your lips and cannot be passed from person to person (not contagious). Canker sores can be very painful, making it difficult to eat and talk. Most canker sores are round or oval white spots with a red border. A burning sensation may occur a few days before the canker sore appears.
There are three types of canker sores: minor, major, and herpetiform. Minor canker sores are usually small and oval shaped with a red edge. Major canker sores are larger and deeper than minor canker sores and are usually round with defined borders. They are extremely painful, and difficult to treat. Herpetiform sores usually affect older people and are not caused by the herpes virus. This type of canker sore is small and usually occurs in clusters that can merge to form one large ulcer.
Canker sores are thought to be caused by a combination of factors that include a minor injury to mouth (from dental work, over-brushing, or an accidental cheek bite), food sensitivities, allergic response to certain bacteria, and emotional stress. Having low levels of vitamin B12, zinc, folate and iron in the diet may also cause canker sores. People with certain conditions, such as celiac disease, inflammatory bowel diseases and immune disorders, may develop canker sores.
Your doctor or dentist can easily diagnose a canker sore by performing a visual exam of your mouth. However, they may perform tests to look for other health problems that can be seen with canker sores. Though canker sores often get better on their own, treatment can include mouthwash, oral medications, nutritional supplements, and the use of a tool or chemical to burn off the affected area. Talk to your doctor to discuss treatment options, especially if your canker sores are very large or will not heal on their own.