A canker sore
Examining a canker sore

Canker Sores

What are canker sores?

Canker sores, also called recurrent aphthous ulcers, are small round sores that form inside the mouth, usually on the loose tissues of the mouth, like the inside of the lips or cheeks, the underside of the tongue, the floor of the mouth, and sometimes near the tonsils.

They usually begin as a tingling sensation, followed by a white or yellow sore surrounded by a bright red area. Pain usually decreases in about a week, and the sores heal in 7 to 14 days.

What causes canker sores?

No one knows what causes canker sores, but some experts say that the tendency to get canker sores is inherited. Another theory is that they may be a result of actions by the body's immune system.

Although we don't know what causes canker sores, these triggers seem to set off an outbreak: injury in the mouth, like a bite or cut; toothpastes that contain sodium lauryl sulfate; emotional stress; food allergies; hormonal changes; and dietary deficiencies, especially Vitamin B, zinc, folic acid, iron, and selenium.

Canker sores are very common; about 20% of the population suffers from them. They usually first appear between ages 10 and 40 years, and are more common in women than men. If you've had canker sores before, you're likely to get them again. Fortunately, canker sores are not contagious.

Treating canker sores

There is no cure for canker sores, but you can ease the pain and perhaps reduce how often you get them. Common remedies include:

• Using toothpastes and mouthwashes that do not contain lauryl sulfate
• Applying over-the-counter remedies that contain numbing agents, like benzocaine or phenol
• Using over-the-counter remedies or mouthwashes that contain antibacterial agents
• Avoiding spicy or acidic foods during an outbreak
• Working with a healthcare provider to identify and treat any food allergies
• Taking a daily multi-vitamin

If this is the first time you've had canker sores, let us know, so we can distinguish them from other kinds of mouth sores. Also let us know if you get canker sores more than three times a year, since this may be a sign of a more serious illness. Fortunately, most canker sores aren't serious, and will soon go away on their own.