Canker Sores (cont.)

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What are symptoms and signs of canker sores?

Canker sores are painful sores inside the mouth. They may occur on the tongue, the lining of the cheeks, the gums, the inside of the lips, or the soft palate on the back of the roof of your mouth. Common symptoms of canker sores include the following:

  • A burning, tingling, or prickling sensation, up to 24 hours before the sore appears
  • Crater-like ulcers that are white, gray, or yellow in color, with a red border
  • Sores are usually painful
  • Difficulty speaking, eating, or swallowing

Less common symptoms that can also indicate a more serious underlying infection include:

Contact your doctor or dentist if your canker sores are

  • larger than usual,
  • spreading,
  • lasting more than three weeks,
  • causing severe pain even after taking over-the-counter pain medication,
  • causing difficulty drinking enough fluids to stay hydrated,
  • accompanied by fever.

Are canker sores the same thing as fever blisters?

No, canker sores are not the same thing as fever blisters (cold sores).

Canker sores occur inside the mouth and are not contagious. Fever blisters are infections caused by the herpes simplex virus (HSV), they mostly occur on the lips and outside of the mouth, and they are very contagious.

Picture of cold sores and canker sores
Picture of cold sores and canker sores

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Medically Reviewed by a Doctor on 9/14/2015

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Canker Sores - Effective Treatments Question: Please describe what treatments have been effective for your canker sores.
Canker Sores - Symptoms Question: What were the symptoms of your canker sores?
Canker Sores - Topical Medications Question: What topical medications have been effective treatments for your canker sores?
Canker Sores - Oral Medications Question: Which medications have you tried for pain or to treat your canker sores? What would you recommend?
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