Canker Sores Health (cont.)

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Canker Sore Symptoms and Signs

Canker sores occur in several forms. They can involve any area of the mouth except for the top of the tongue, lips, and hard palate.

  • Minor canker sores (which account for the majority of aphthous ulcers) are oval and less than 10 mm (1/3 inch) across. Most are 2-3 mm with a white center. They are painful but clear up within three to 14 days without scarring. It is unusual for them to become infected.
  • Major canker sores consist of deep ulcers measuring greater than 1 cm (1/3 inch). These ulcers, which are very painful, have irregular margins and often last for three to six weeks. They tend to heal with extensive scarring.
  • A third form of canker sores, termed "herpetiform," resemble herpes infections and consist of many small shallow punched-out lesions, pinhead-sized (1-3 mm) in diameter, or less than 1/10 of an inch. Clusters of these sores may merge together to form large irregular ulcers. They last from seven to 10 days.
  • Canker sores commonly come back. Some people have a few outbreaks a year, while others can have them almost all the time.

When to Seek Medical Care

You should seek medical attention if any of the following occur:

  • It is your first episode and you are not sure about the diagnosis.
  • The pain worsens and you cannot control it.
  • You have diarrhea. This may indicate you are having a systemic problem like Crohn's disease or ulcerative colitis.
  • You have ulcers in places other than the mouth. This may indicate that you have a disease called Behçet 's syndrome or possibly a sexually transmitted disease.
  • Lesions persist beyond three weeks.
    • Lesions lasting over three weeks raise the concern for oral cancer or inflammatory bowel disease (ulcerative colitis or Crohn's disease).
    • Factors that may increase the risk of oral cancer include smoking, tobacco chewing, and use of alcohol.
Medically Reviewed by a Doctor on 5/8/2014

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