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Canker Sore

Canker sores or aphthous ulcers refer to small, superficial lesions that occur at the base of your gums or the soft tissues of your mouth. Canker sores are not similar to cold sores as they do not develop on the surface of the lips and they are not contagious. However, canker sores can be painful and may also cause discomfort while eating.

Canker sores usually disappear within a week or so without any treatment.  Seek medical help if your canker sore seems unusually large or does not heal.

Signs and symptoms

Canker sores are usually round or oval are often white or yellow in the center and red around the border. Canker sores can develop in mouth such as your tongue, the base of your gums, inside your cheeks, inside your lips or on the soft palate. You may experience a burning or tingling sensation in your mouth prior to appearance of the sore.

There are many types of canker sores, which include:

  1. Minor canker sores
  • Small
  • Oval shaped
  • Heal without scarring – within one to two weeks

2.  Major canker sores

  • Larger and deeper compared to minor sores
  • Irregular edges
  • Takes around six weeks to heal with scarring

3.  Herpetiform canker sores

  • Pinpoint size
  • Occur in clusters from 10-100 sores
  • Irregular edges
  • Heal without scarring – within one to two weeks

When to seek medical help

See you doctor if you experience:

  • An abnormally large canker sore
  • Recurring canker sores – new ones may develop before the old sores even heal
  • Persistent symptoms of sores that last more than three weeks
  • Sores that may develop to the lips
  • Pain that does not resolve with self-treatment measures
  • Difficulty drinking or eating
  • High fever accompanied with the canker sore

See your dentist if you suspect that the sharp surfaces of your teeth or dental appliances are causing canker sores.


Minor canker sores usually do not require any treatment as they tend to disappear on their own within one to two weeks. However, large, painful and persistent sores may require medical care. There are many treatment options for canker sores including mouthwash, topical rinses, and corticosteroids for severe cases.

  • Mouth rinses. For several canker sores, your may be directed to use a mouth rinse consisting of steroid dexamethasone to treat pain and inflammation.
  • Topical ointment, you can use prescription topical pastes or over-the-counter pastes consisting of active ingredients like benzocaine, amlexanox and fluocinonide that control pain and speed up the healing process when applied to canker sores as soon as they begin to develop in your mouth. You may be directed by your doctor to apply the past two to five times per day until symptoms subside.
  • Oral medication. You can use oral medication that may not be specifically intended for canker sores. Your doctor may tell you to use oral steroid medication in case of severe canker sores that do not respond to other treatment methods.

Nutritional supplements. Your doctor may prescribe to take nutrient supplements such as vitamin B-6, vitamin B-12, folate and zinc, if you do not consume enough of these nutrients from your diet.

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