Canker Sores

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. Continue Reading
Reviewed on 9/14/2015
Dental Health Pictures Slideshow: Top Problems in Your Mouth


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