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Symptoms
By Mayo Clinic staff
Most canker sores are round or oval with a white or yellow center and a red border. They form inside your mouth — on or under your tongue, inside your cheeks or lips, at the base of your gums, or on your soft palate. You might notice a tingling or burning sensation a day or two before the sores actually appear.
There are several types of canker sores, including minor, major and herpetiform sores.
Minor canker sores
These most common canker sores:
- Are usually small
- Are oval shaped
- Heal without scarring in one to two weeks
Major canker sores
These less common sores:
- Are larger and deeper than minor canker sores
- Have irregular edges
- May take up to six weeks to heal and can leave extensive scarring
Herpetiform canker sores
These canker sores, which usually develop later in life:
- Are pinpoint size
- Often occur in clusters of 10 to 100 sores
- Have irregular edges
- Heal without scarring in one to two weeks
When to see a doctor
Consult your doctor if you experience:
- Unusually large canker sores
- Recurring sores, with new ones developing before old ones heal
- Persistent sores, lasting three weeks or more
- Sores that extend into the lips themselves (vermilion border)
- Pain that you can't control with self-care measures
- Extreme difficulty eating or drinking
- High fever along with canker sores
See your dentist if you have sharp tooth surfaces or dental appliances that seem to trigger the sores.
- Kliegman RM, et al. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa.: Saunders Elsevier; 2011. http://www.mdconsult.com/das/book/body/208746819-6/0/1608/0.html. Accessed Feb. 2, 2012.
- Long SS, et al., eds. Principles and Practice of Pediatric Infectious Diseases. 3rd ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2008. http://www.mdconsult.com/das/book/body/174218004-3/925169573/1679/31.html#4-u1.0-B978-0-443-06687-0..50030-8--cesec16_721. Accessed Feb. 2, 2012.
- Flint PW, et al. Cummings Otolaryngology: Head & Neck Surgery. 5th ed. Philadelphia, Pa.: Mosby Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-323-05283-2..X0001-8--TOP&isbn=978-0-323-05283-2&uniqId=230100505-57. Accessed Feb. 2, 2012.
- Canker sores, cold sores & common mouth sores. American Dental Association. http://www.ada.org/2982.aspx?currentTab=1. Accessed Feb. 2, 2012.
- Stomatitis. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/dental_disorders/symptoms_of_dental_and_oral_disorders/stomatitis.html. Accessed Feb. 2, 2012.
- Rakel D. Integrative Medicine. 2nd ed. Philadelphia, Pa.: Saunders Elsevier; 2007. http://www.mdconsult.com/das/book/body/208746819-2/0/1494/0.html. Accessed Feb. 6, 2012.
- Goldstein BG, et al. Oral lesions. http://www.uptodate.com/home/index.html. Accessed Feb. 6, 2012.
- AskMayoExpert. Recurrent aphthous ulcers. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2011.
- Morelli V, et al. Alternative therapies for common dermatologic disorders, part 2. Primary Care Clinics in Office Practice. 2010;37:285.
- Bailey J, et al. What is the most effective way to treat recurrent canker sores? The Journal of Family Practice. 2011;60:621.
- Messadi DV, et al. Aphthous ulcers. Dermatologic Therapy. 2010;23:281.
- Gibson LE (expert opinion). Mayo Clinic, Rochester, Minn. Feb. 21, 2012.
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