Canker Sore Symptoms and Signs
Canker sores occur in several forms. They can involve any area of the mouth except for the top of the tongue, lips, and hard palate.
* Minor canker sores (which account for the majority of aphthous ulcers) are oval and less than 10 mm (1/3 inch) across. Most are 2-3 mm with a white center. They are painful but clear up within three to 14 days without scarring. It is unusual for them to become infected.
* Major canker sores consist of deep ulcers measuring greater than 1 cm (1/3 inch). These ulcers, which are very painful, have irregular margins and often last for three to six weeks. They tend to heal with extensive scarring.
* A third form of canker sores, termed "herpetiform," resemble herpes infections and consist of many small shallow punched-out lesions, pinhead-sized (1-3 mm) in diameter, or less than 1/10 of an inch. Clusters of these sores may merge together to form large irregular ulcers. They last from seven to 10 days.
* Canker sores commonly come back. Some people have a few outbreaks a year, while others can have them almost all the time
