Canker sores are small (usually less than 1 centimeter in diameter) ulcers that appear on the inside of the mouth. The sores may be painful, and may be preceded by a burning or tingling sensation before they appear. Canker sores tend to be oval in shape, often with a whitish center and reddish border. They usually go away on their own, without treatment, although they may reappear frequently in persons who have a history of having had them before. Between 20 to 40% of Americans have canker sores at some point, and they tend to appear more in women than in men. Their appearance tends to peak in adolescence and young adulthood and decrease with age. Canker sores are not contagious.
What causes canker sores?
No one really knows. Hereditary and environmental causes have been suggested, but not proved. Outbreaks of canker sores are often associated with one or more of the following triggers:
• Anxiety or stress; students often develop canker sores at "exam time."
• Minor oral injuries from dental work or braces or overzealous brushing.
• Food sensitivities, such as to chocolate, tomatoes, or acid fruits.
• Hormonal changes related to menstruation.
• Toothpastes or mouthwashes containing sodium lauryl sulfate.
• Iron, vitamin B12, zinc, or folic acid deficiencies.
• Sensitivity to common drugs such as ibuprofen, atenolol, and beta-blockers.
Canker sores may also appear in conjunction with other conditions, such as celiac disease, Crohn's disease and other inflammatory bowel irritations, or diseases that suppress the immune system.
Are canker sores the same thing as cold sores?
No. Cold sores (sometimes called fever blisters or herpes simplex type 1) are caused by a virus, and are contagious. They typically appear on the outside of the mouth – on or around the lips, under the nose, or on the chin – as opposed to canker sores, which almost always occur inside the mouth.
Do I need to see a doctor?
You rarely need to see a doctor unless you experience extreme symptoms such as high fever, sluggishness, or swollen lymph nodes. You should be concerned if you experience unusually large sores or clumps of sores, sores that seem to be spreading, or sores that last for more than three weeks, or do not seem to heal. Also see a doctor if you experience intolerable pain, even after avoiding foods and liquids that trigger sensitivity in the sores.
How are canker sores treated?
If the pain and discomfort of canker sores is minor, they usually go away within a week or two without any treatment. If the pain is more severe, you can alleviate it with over-the-counter medications such as aspirin or ibuprofen. You should avoid hot, spicy, and overly acidic foods, especially if they seem to trigger pain in the sores themselves. There are common over-the-counter medications that can be used to soothe the painful areas, but there are common home remedies as well. One is to create a mixture of half water and half hydrogen peroxide and dab it on the sores, followed by a dab of Milk of Magnesia. Another is to mix Milk of Magnesia and Benadryl liquid allergy medicine in equal proportions and swish the mixture in your mouth for a minute or two before spitting it out.
What can I do to prevent canker sores?
If your canker sores keep coming back, make sure that your diet is not deficient in vitamin B12 and zinc. Reduce mouth irritation by avoiding hard, crunchy, or spicy foods and gum-chewing. Brushing your teeth and flossing after meals may help to remove leftover food items that could trigger irritation. If the cause of the sores seems related to some oral trauma or injury, remove or replace any source of irritation, such as ill-fitting dental appliances.