Canker Sores: What They Are and How To Treat Them

At one point or another, most of us have suffered a canker sore – not to be confused with a cold sore that appears on the surface of your lips. Canker sores are the ones on the inside of your mouth with a white or yellowish center and a very red border.

Medically speaking, canker sores are a relatively minor problem. That doesn’t mean they don’t cause a lot of annoyance and make simple tasks like eating uncomfortable. About one fifth of the world’s population gets them over and over, a condition called recurrent aphthous stomatitis (RAS).

Doctors currently don't know a lot about the causes of canker sores or how to cure them, but they do know they’re not contagious and usually go away on their own within 10-14 days.  And there are some treatments that can help manage pain, reduce healing time, and avoid getting them.

About Canker Sores

Canker sores are ulcers that can appear anywhere on the inside of your mouth, including your gums. Most of them are less than 1 cm wide and shallow. It’s common to feel a burning or stinging sensation before they show up.

Some canker sores – less than 10 percent – can be large in size, last longer, and may leave a scar when they heal. These are more common in people who have a suppressed (weakened) immune system.

A very small percentage of canker sores will show up as a cluster of small ulcers all at the same time. These “herpetiform canker sores” look similar to a viral infection, but are not actually caused by one.

Canker Sores vs. Cold Sores

Cold sores, or fever blisters, usually show up on  your lips and look like small blisters. They’re caused by a type of herpes virus. They can last about as long as canker sores and they are contagious. If you want more information about cold sores, you can read this article.

Who Gets Canker Sores?

Anyone can get canker sores. They seem to run in families and they’re more common in:

  • Adolescents and  young adults
  • Women (especially around your period)
  • Smokers
  • People under stress
  • People with food allergies or lack of  iron, folic acid, or vitamin B-12 in their diet

You can also get canker sores if your mouth is hurt from dental work, an accidental bite on the inside of your mouth from your teeth, or even brushing your teeth too hard. Some people have even gotten them from using toothpaste with sodium lauryl sulfate.

Canker Sore Treatment Options

Once you have a canker sore, the best outcome that you can get from treatment is reducing pain and speeding up healing. Here are a few things that you can do:

  • Stay away from hot or spicy foods because they can irritate your mouth
  • Try mild over-the-the counter mouthwashes or saltwater rinses
  • See your doctor if you’re feeling miserable, and:
    • The canker sore doesn’t go away after two weeks or it’s getting progressively worse; or
    • You have other health issues along with the sore (fever, diarrhea, headache, skin rash)

If you get canker sores more than three times a year, it’s a good idea to have a discussion with your doctor. They might suggest other prescription medications and treatments to reduce pain and speed up healing:

  • Anti-inflammatory prescription creams or ointments to apply to the sore
  • Silver nitrate cautery to “burn” the canker sore
  • Montelukast (an asthma medicine) might reduce the number of canker sores people get
  • Other oral medications – since these pills can have significant side-effects, they aren’t typically used as a treatment option

Other Canker Sore Remedies You Can Try

Two dietary supplements show promise for reducing how often canker sores appear and the amount of pain they can cause. Since these are relatively cheap and don’t have many negative side effects, they might be worth a try if you have a canker sore that’s bothersome:

  • Vitamin B-12: 1000 mcg/day in sublingual (under the tongue) form, and
  • Omega-3 fatty acids: 1,000 mg/day

Multivitamins haven’t shown the same promise for reducing the problem of recurrent canker sores.

Bonus reading:  The Aurora Journal of Patient-centered Research and Reviews provides a review of research and current treatments for recurrent aphthous stomatitis.

Meet the Author

Jillian Michelle Hudson, MD is a Family Medicine physician at Lakeshore Medical Clinic in South Milwaukee, Wisconsin.

Read more posts from this author

The information presented in this site is intended for general information and educational purposes. It is not intended to replace the advice of your own physician. Contact your physician if you believe you have a health problem.

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