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Canker Sores: Causes, Relief & Treatments

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Canker Sores: What You Should Know

Canker sores are small, painful ulcers that occur inside the mouth, on the lips, tongue, gums, and cheeks, or in the throat. In general, they are white or yellow with a red border and are less than a half inch in size. They can occur one at a time or in groups.


Canker sore symptoms are relatively consistent. You'll usually feel a burning or tingling sensation on the spot where the canker sore is forming. And once it does form, it will be painful, but can usually be managed through self-care.


There are generally two types of cankers sores. The most common are known as simple canker sores, and can occur three to four times a year for about a week or two at a time. The second are known as complex canker sores. These are typically larger and have a longer healing time, and are more likely in people who've had canker sores before.

What Causes Canker Sores?

The exact cause of canker sores isn't known, but there are a few things which can make them more likely to happen.


  • Family history
  • Acidic foods
  • Vitamin or mineral deficiencies
  • Hormonal changes
  • Stress
  • Allergies to medications
  • Oral injuries from biting part of the mouth or dental appliances like braces and dentures
  • Underlying health conditions like celiac disease, Crohn's disease, or an impaired immune system

How to Treat Canker Sores?

Because canker sores heal on their own, there isn't a specific treatment for them. However, you can treat the pain they cause with topical creams or gels. You can also reduce discomfort by rinsing your mouth regularly with warm water and eating bland foods.


In cases where the canker sores are large or haven't healed after two to three weeks, your dentist or doctor may prescribe a topical or ingestible steroid to keep the sore from growing and speed healing time.


It's a good idea to speak to your dentist or doctor if you have canker sores for the first time, are getting them very frequently, or also have a high fever at the same time. They may want to run some tests to help rule out other health conditions or correct issues that are causing the sores.

Common Questions about Canker Sores

Is a Canker Sore the same as a Cold Sore?

Although many people confuse canker sores for cold sores, they are two different things. A cold sore (sometimes called a fever blister) is caused by the herpes simplex 1 virus. Because cold sores are caused by a virus, they're very contagious, while a canker sore cannot be passed from person to person.


One way to tell the difference between a cold sore and canker sore is its location. Cold sores usually show up outside the mouth and canker sores occur inside the mouth.

How Long do Canker Sores Last?

Canker sores are usually painful for 3-10 days, and heal on their own within a week or two. If you have a canker sore that lasts longer, you should contact your dentist or doctor. Crest CA-EN Maybach Article-Promo-700x225 092418 (1)

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