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Canker Sores - Topic Overview

What is a canker sore?

A canker sore is a shallow sore shaped like a crater (ulcer) on your tongue or on the inside of your lip or cheek. Canker sores have a red border and a white or yellow center. They may be painful and can make it hard to talk and eat. You may have one or more than one canker sore at a time. Unlike cold sores, you cannot spread canker sores to other people. See a picture of canker sorescamera.gif.

Anyone can get a canker sore, but women, teens, and young adults have them more often. Most people have canker sores at some time in their lives, and some people have them regularly.

What causes a canker sore?

The cause of canker sores is unknown, but they tend to run in families. Canker sores are not contagious.

Canker sores may also develop when you:

  • Are stressed or tired.
  • Have your menstrual cycle, if you are a woman.
  • Hurt your mouth, such as biting your lip.
  • Have braces on your teeth.
  • Have food allergies. Eating foods that you are allergic to may cause you to get a canker sore.
  • Eat or drink food or juice that has a lot of acid, such as orange juice.
  • Do not get enough vitamins or minerals in your diet, such as iron, vitamin B12, and folic acid..

What are the symptoms?

The main symptom of a canker sore is getting a shallow ulcer on your tongue or on the inside of your lip or cheek. The sore may be large or small, and it will have a red border and a white or yellow center. You might have more than one canker sore at a time.

Canker sores usually begin with a burning or tingling feeling. They may be swollen and painful. Having a canker sore can make it hard to talk or eat.

Canker sores may hurt for 7 to 10 days. Minor canker sores heal completely in 1 to 3 weeks, but major canker sores can take up to 6 weeks to heal. Some people get another canker sore after the first sore has healed. Most canker sores heal without a scar.

How is a canker sore diagnosed?

If you see your doctor or dentist about the pain caused by your canker sores, he or she will do a physical exam by looking in your mouth to diagnose the canker sores.

How is it treated?

You do not need to see a doctor for most canker sores. They will get better on their own. There are many things you can try at home to relieve the pain caused by your canker sores:

  • Eat soft, bland foods that are easy to swallow, such as yogurt or cream soup. Cut your food into small pieces or mash or puree it. Avoid coffee, chocolate, spicy or salty foods, citrus fruits or juices, nuts, seeds, and tomatoes.
  • Drink cold fluids, such as water or iced tea, or eat Popsicles. Sometimes fluid touching the canker sore can cause a stinging pain. Use a straw so the fluid doesn't touch the canker sore. Hold ice on the canker sore until it is numb.
  • Carefully brush your teeth so you don't touch the sore with the toothbrush bristles.
  • Rinse your mouth with salt water. To make a salt water rinse, dissolve 1 tsp (5 g) of salt in 1 cup (250 mL) of warm water.
  • Buy an over-the-counter medicine, such as Anbesol, milk of magnesia, or Orabase, to put on your canker sores. Use a cotton swab to apply the medicine. Put it on your sores 3 to 4 times a day.
  • Take a pain reliever, such as nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin (such as Bayer), ibuprofen (such as Advil), or naproxen (such as Aleve). Do not give aspirin to anyone younger than 20 because of the risk of Reye syndrome.
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WebMD Medical Reference from Healthwise

Last Updated: September 14, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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