Also known as aphthous ulcers or canker sores, mouth ulcers are painful open sores inside the mouth. The exact cause of mouth ulcers is unknown, though a combination of factors may contribute, including minor mouth injuries, vitamin deficiencies, and stress.
The ulcer forms a small, pale pit, and the area around it may become swollen.
Most ulcers clear up by themselves within about 3 weeks.
Symptoms may be relieved by over-the-counter antiseptic mouthwashes, pain relievers, corticosteroid lozenges, or anesthetic gels.
A doctor or dentist should be consulted if an ulcer lasts for more than about 3 weeks or becomes more painful or red, or if ulcers keep recurring.