Aphthous ulcers are painful sores inside the mouth, gums, or lips. They are also called canker sores. The sores can occur one at a time or as a group. Canker sores are temporary and usually not serious.
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The cause of canker sores is not known. They may be an overreaction of the immune system.
Canker sores are more common in children and adolescents. They may also run in families.
Things that raise the risk of canker sores are:
Medical conditions that may raise the risk of canker cores are:
Canker sores can be various sizes. They typically occur on the inner cheeks and lips, and on or under the tongue. Canker sores are open, shallow, grayish sores. They may have a raised, yellowish-white border surrounded by a red border.
Some people get canker sores 2 to 3 times per year. Others get sores often. The sores may be painful for 3 to 4 days.
Minor sores may last for a total of 7 to 14 days. Major sores can last for several weeks or even months. They may leave a scar after they heal.
The doctor will ask about your symptoms and health history. A physical exam may be done. The doctor may diagnose the sore based on how it looks.
Tests may be done to rule out other causes. They may be:
Most canker sores heal on their own within 1 to 2 weeks. Larger sores may take up to 6 weeks to heal. Treatment is not usually needed.
If canker sores are very painful, the doctor may advise:
It is not always possible to prevent canker sores. To help reduce the risk:
Family Doctor—American Academy of Family Physicians
Mouth Healthy—American Dental Association
The College of Family Physicians of Canada
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Canker sores. Family Doctor—American Academy of Family Physicians website. Available at: https://familydoctor.org/condition/canker-sores. Accessed February 25, 2021.
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Last reviewed January 2021 by EBSCO Medical Review Board Marcin Chwistek, MD Last Updated: 2/25/2021