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What is a canker sore?

Aphthous stomatitis is an illness that causes small ulcers to appear in the mouth, usually inside the lips, on the cheeks, or on the tongue. Aphthous ulcers are also known as "canker sores."


The following are the most common signs and symptoms of aphthous stomatitis. However, each child may experience symptoms differently. Signs and symptoms may include:

  • Ulcers in the mouth, usually inside the lips, on the cheeks, or on the tongue
  • Ulcers that are covered with a yellow layer and have a red base
  • No fever present (in most cases)

Lesions usually heal in seven to 14 days and tend to recur.


The exact cause of canker sores is not known. However, there are many factors that are thought to be involved with their development, including:

  • Weakened immune system
  • Allergies to food such as coffee, chocolate, cheese, nuts and citrus fruits
  • Stress
  • Viruses and bacteria
  • Trauma to the mouth
  • Poor nutrition
  • Certain medications

Aphthous stomatitis is usually first seen in children and adolescents from the ages of 10 to 19 years. For about one-third of the children affected, lesions continue to reappear for years after the initial outbreak.

These ulcers are not contagious and cannot be spread from one child to another.

How is it diagnosed?

Aphthous stomatitis is usually diagnosed based on a complete history and physical examination of your child. The lesions are unique and usually allow for a diagnosis simply on physical examination. In addition, your child's doctor may order the following tests to help confirm the diagnosis and rule out other causes for the ulcers:

  • Blood tests
  • Cultures of the lesions
  • Biopsy of the lesion—taking a small piece of tissue from the lesion and examining it microscopically

Treatment options

Specific treatment for aphthous stomatitis will be determined by your child's doctor based on:

  • Your child's age, overall health and medical history
  • Extent of the disease
  • Your child's tolerance for specific medications, procedures or therapies
  • Expectations for the course of the disease
  • Your opinion or preference

The goal of treatment for aphthous stomatitis is to help decrease the severity of the symptoms. Since it is not a viral or bacterial infection, antiviral medications and antibiotics are ineffective. Treatment may include:

  • Increased fluid intake
  • Acetaminophen for any fever or pain
  • Proper oral hygiene
  • Topical medications (to help decrease the pain of the ulcers)
  • Mouth rinses (to help ease the pain)

It is especially important for your child to avoid spicy, salty, or acidic foods, which may cause further mouth irritation.