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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, and at the base of your gums. 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 less than about 1/2 inch, or 12 millimeters (mm), in diameter
- Are oval shaped
- Heal without scarring in one to two weeks
Major canker sores
These less common sores:
- Are greater than about 1/2 inch, or 12 mm, in diameter
- Have irregular edges
- May take up to six weeks to heal and leave extensive scarring
Herpetiform canker sores
These canker sores, which usually develop later in life:
- Are each no bigger than about 1/8 inch, or 3 mm, in diameter
- Often occur in clusters of 10 to 100 sores
- Have irregular edges
- Heal without scarring in one to two weeks
Additional symptoms
Occasionally, you may experience other signs or symptoms along with the lesions, such as:
- Fever
- Listlessness
- Swollen lymph nodes
When to see a doctor
Consult your doctor if you experience:
- Unusually large canker sores
- Recurring ulcers, 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.
- Morelli JG. Disorders of the mucous membranes. In: Kliegman RM, et al. Nelson Textbook of Pediatrics. 18th ed. Saunders Elsevier; 2007. http://www.mdconsult.com/das/book/body/174218004-3/925169573/1608/1550.html#4-u1.0-B978-1-4160-2450-7..50665-4--cesec7_12116. Accessed Dec. 4, 2009.
- Leggiadro RJ. Infections of the oral cavity. In: 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 Dec. 4, 2009.
- Travers JB, et al. Physiology of the oral cavity. In: Cummings CW, et al. Otolaryngology: Head & Neck Surgery. 4th ed. http://www.mdconsult.com/das/book/body/174218004-4/0/1263/586.html?tocnode=49543605&fromURL=586.html#4-u1.0-B0-323-01985-4..50067-8--cesec61_2453. Accessed Dec. 4, 2009.
- Common mouth sores. American Dental Association. http://www.ada.org/public/topics/mouth_sores.asp. Accessed Dec. 4, 2009.
- Mouth sores. The Merck Manuals: Home Edition for Patients and Caregivers. http://www.merck.com/mmhe/sec08/ch112/ch112a.html. Accessed Dec. 4, 2009.
- Amsterdam JT. Oral medicine. In: Marx JA, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. St. Louis, Mo.: Mosby; 2006. http://www.mdconsult.com/book/player/book.do?method=display&type=bookPage&decorator=header&eid=4-u1.0-B978-0-323-05472-0..00068-2--s0160&uniq=174218004&isbn=978-0-323-05472-0&sid=925188259.Accessed Dec. 4, 2009.
- Rakel D, et al. Recurrent aphthous ulceration. In: Rakel RE. Integrative Medicine. Philadelphia, Pa.: Saunders Elsevier; 2007. http://www.mdconsult.com/das/book/body/174218004-8/925191198/1494/118.html#4-u1.0-B978-1-4160-2954-0..50075-2_3684. Accessed Dec. 4, 2009.
- Gibson LE (expert opinion). Mayo Clinic, Rochester, Minn. Dec. 9, 2009.
