Canker Sores are also known as aphthous ulcers and are part of the most common cause of stomatitis. The sores are pale white or yellowish in color with a red outer ring.

Canker sores can develop singly or in a cluster and usually occur on the inside of the lips or cheek, or on the tongue.

Canker sores lead to acute, temporary pain. In minor cases, the ulcers heal within 4-14 days. In more severe cases, which account for about 1 in 10 of all cases of stomatitis, the sores can last up to 6 weeks.

Anyone can get canker sores, although women and people in their teens and 20s are more likely to experience them. They can run in families but are not contagious.