There are aphthous ulcers (canker sores) on the right of the image at the corner of the mouth, just below the tongue, and also a shallow ulcer on the lower lip on the left.
There are aphthous ulcers (canker sores) on the right of the image at the corner of the mouth, just below the tongue, and also a shallow ulcer on the lower lip on the left.
This image displays a shallow ulcer inside the mouth, typical of an aphthous ulcer (canker sore).
This image displays a shallow ulcer inside the mouth, typical of an aphthous ulcer (canker sore).
This image displays a shallow aphthous ulcer (canker sore).
This image displays a shallow aphthous ulcer (canker sore).
This image displays multiple aphthae (canker sores), lesions with a white center and red surround.
This image displays multiple aphthae (canker sores), lesions with a white center and red surround.
This image displays a larger-than-usual aphtha (canker sore), with the typical white erosion.
This image displays a larger-than-usual aphtha (canker sore), with the typical white erosion.
This image displays a large, healing aphtha (canker sore) on the lower lip.
This image displays a large, healing aphtha (canker sore) on the lower lip.

Images of Canker Sore (Aphthous Ulcer) (6)

There are aphthous ulcers (canker sores) on the right of the image at the corner of the mouth, just below the tongue, and also a shallow ulcer on the lower lip on the left.
This image displays a shallow ulcer inside the mouth, typical of an aphthous ulcer (canker sore).
This image displays a shallow aphthous ulcer (canker sore).
This image displays multiple aphthae (canker sores), lesions with a white center and red surround.
This image displays a larger-than-usual aphtha (canker sore), with the typical white erosion.
This image displays a large, healing aphtha (canker sore) on the lower lip.

Canker Sore (Aphthous Ulcer)

Canker sores (aphthous ulcers), or aphthae, are the most common cause of periodic (recurring) ulcers of the oral and genital linings (mucous membrane surfaces). Their cause is unknown, but stress, lack of sleep, mechanical injury (trauma), and perhaps some vitamin deficiencies, toothpastes, and foods can make the condition worse. Some people with anemia and other medical conditions that weaken the immune system may be more likely to develop canker sores.

There are 3 types of canker sore:

  • Minor aphthae (80% of cases)
  • Major aphthae (Sutton disease, approximately 10% of cases)
  • Herpetiform aphthae (10% of cases)

Minor aphthae heal within 1–2 weeks.

Major aphthae are extremely painful, last from 2–4 weeks, and generally cause scars after they heal.

Herpetiform aphthae progress in a way that is similar to minor aphthous ulcers.

Who's At Risk?

Canker sores affect approximately 25% of the general population. They are more common in women, and they usually start to appear in children or teens.

People infected with HIV/AIDS are often severely affected.

Signs & Symptoms

The most common locations of canker sores are inside the mouth or lips or on the tongue. The genitals may also be affected. Ulcers can have a white, gray, or yellow base.

  • Minor aphthae are single or multiple lesions, 1.0 cm or less in diameter.
  • Major aphthae are deep ulcers greater than 2.0 cm in diameter.
  • Herpetiform aphthae appear as multiple ulcerations.

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Self-Care Guidelines

None usually necessary except gentle oral care. There is no cure for canker sores, but the following measures may help relieve the pain associated with them:

  • Apply protective pastes to form a barrier over the ulcer.
  • Apply local anesthetics (benzocaine, lidocaine) to help numb the area.
  • Use antibacterial mouthwashes.
  • Avoid products or foods that seem to trigger episodes.
  • Maintain a good diet or take vitamins.
  • Get enough sleep and reduce stress.
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Treatments

Most people are treated with topical steroids or other medications applied to the affected area, to speed up healing of the lesions. These include:

  • Topical calcineurin inhibitors (tacrolimus or pimecrolimus).
  • Prednisone may be used in severe situations.
  • Other oral medications, dapsone and colchicine, may be used in more severe cases, when repeated outbreaks (recurrences) continue for years.

Visit Urgency

See your child’s doctor for evaluation if canker sores do not heal, occur frequently, or are extremely uncomfortable or painful.

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References

Bolognia, Jean L., ed. Dermatology, pp.419, 1087. New York: Mosby, 2003.

Freedberg, Irwin M., ed. Fitzpatrick’s Dermatology in General Medicine. 6th ed. pp.1115-1116, 1098-1099, 2360, 2467. New York: McGraw-Hill, 2003.