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Canker Sores (Aphthous Ulcers)
Canker sores are small shallow ulcers that appear in the mouth and often make eating and talking uncomfortable. There are two types of canker sores:
What causes canker sores?
The exact cause of most canker sores is unknown. Stress or tissue injury is thought to be the cause of simple canker sores. Certain foods—including citrus or acidic fruits and vegetables (such as lemons, oranges, pineapples, apples, figs, tomatoes, strawberries)—can trigger a canker sore or make the problem worse. Use of nonsteroidal anti-inflammatory drugs, like Motrin, is another common cause. Sometimes a sharp tooth surface or dental appliance, such as braces or ill-fitting dentures, might also trigger canker sores.
Some cases of complex canker sores are caused by an underlying health condition, such as an impaired immune system; nutritional problems, such as vitamin B-12, zinc, folic acid, or iron deficiency; and gastrointestinal tract disease, such as Celiac disease and Crohn's disease.
Are cold sores another name for canker sores?
No, although these sores are often confused for each other, they are not the same. Cold sores, also called a fever blister or herpes simplex type 1, are groups of painful, fluid-filled blisters. Unlike canker sores, cold sores are caused by a virus and are extremely contagious. Also, cold sores typically appear outside the mouth—usually, under the nose, around the lips, or under the chin while canker sores occur inside the mouth.
What are the symptoms of canker sores?
You may have a canker sore if you have:
In severe attacks, you may also experience:
How are canker sores treated?
Pain from a canker sore generally lessens in a few days and the sores usually heal without treatment in about a week or two.
If sores are large, painful, or persistent, your dentist may prescribe an antimicrobial mouth rinse, a corticosteroid ointment, or a prescription or nonprescription solution to reduce the pain and irritation.
Can canker sores be prevented?
Although there is no cure for canker sores and they often reoccur, you may be able to reduce their frequency by:
You should call your dentist if you have:
Reviewed by the doctors at The Cleveland Clinic Department of Dentistry.
Last Editorial Review: 11/20/2007
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