What Is a Mouth Sore or Canker Sore and What Are the Causes?

People often use the terms "canker sores" and "cold sores" interchangeably. While both are very painful, a canker mouth sore is found on the inside of the mouth and is not contagious; cold sores are located on the inside or outside of the mouth and are contagious.

Canker Sores:

These sores are found inside the cheeks, on your tongue or the bottom of your mouth, and sometimes on your gums. They range from the size of a tiny pinhead to a penny. The sores are grayish-white in the center and circled with a red inflammation. Since it's an open mouth sore, it hurts when touched by anything, including saliva. They can burn and itch, too.

Canker sores might be called the "stress sores," because they are caused by different types of stress:

  • Emotional stress;
  • Physical stress, such as biting your tongue, burning your mouth, or an abrasion from braces or loose dentures; or
  • Chemical stress producing changes in your body, perhaps resulting from an illness or change in eating habits (such as medications, or too much of acidic foods such as tomatoes, grapefruit, or lemons).

About one in five people get them. Women in the 20-to-50 year age group get them more often. Once you get them, you're likely to experience them again. However, they usually go away after seven to ten days, although some can be longer-lasting.

An antimicrobial mouth rinse may lessen the irritation. Temporary relief can be provided by over-the-counter topical anesthetics. Pain relief varies with different products. Some medications provide a protective film that physically blocks contact with food and saliva, lessening irritation.

Good oral hygiene and a healthy diet are preventive measures for reducing the frequency of outbreaks.

Cold Sores

Also known as fever blisters, cold sores are caused by the virus herpes simplex. These are painful blisters that usually break out around the lips and sometimes under the nose or chin and normally heal within one week. They are very contagious. The virus stays in the body, causing recurrent lesions prompted from a fever, sunburn, skin abrasions, or stress.

They can be treated by your dentist with the same topical anesthetics to relieve pain and irritation as for canker sores. Prescription antiviral drugs can be effective in reducing viral infections that cause flare-ups.

Additionally, there are new topical medications (ointments) now available that shorten the duration of a breakout, when applied immediately after the cold mouth sore is noticed. All antiviral medications work best in the prodromal or early stage of the lesion. If the wound is open and sore, these medications are of little use as the healing time is still the same.

Be sure to consult with your dentist when any mouth sores do not heal.

By Brian J. Gray, DDS, MAGD, FICO

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