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Aphthous Stomatitis (Canker Sores)

What is an Aphthous Stomatitis (Canker Sore)?

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.


The exact cause of this disease is not known. There are many factors that are thought to be involved with the development of canker sores, including:

  • A challenged immune system (while fighting another illness)
  • Certain foods may cause the lesions to appear, such as:
    • Coffee
    • Chocolate
    • Cheese
    • Nuts
    • Citrus fruits
    • Potatoes
  • Stress
  • Viruses and bacteria
  • Trauma to the mouth (including poor tooth brushing technique)
  • Poor nutrition
  • Certain medications

A canker sore is usually seen in children and teens from the ages of 10 to 19 years. For about a third of the children affected, lesions continue to reappear for years after the initial outbreak. Some ulcers in young children (younger than 10) may be linked with a specific viral infection. Please see your doctor or dentist if your child has any ulcers in their mouth.

Signs and Symptoms

The following are the most common symptoms of canker sores. However, each child may have only some of the following symptoms:

  • Painful 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 (in most cases)
  • Lesions usually heal in seven to 14 days and tend to come back


A canker sore is usually diagnosed based on a complete medical history and physical exam of your child. The lesions are unique and usually allow for a diagnosis simply on physical exam. Your child's doctor may also 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


Your child's doctor will select a treatment for the canker sore 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 a viral infection, antibiotics are ineffective. Treatment may include

  • Increased fluid intake (i.e., water, Gatorade, Pedialyte, popsicles)
  • Acetaminophen (Tylenol) or ibuprofen (Motrin) for any fever or pain. Do not give ibuprofen to children under the age of 6 months old.
  • Proper oral hygiene that is supervised (brush teeth for two minutes twice a day)
  • Topical medications (to help decrease the pain of the ulcers); use Vaseline on dry lips
  • Mouth rinses (to help ease the pain); salt water (½ teaspoon of table salt mixed with 8 ounces of water)

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

Last Updated 07/2021

Reviewed By Sarat Thikkirussy, DDS, MS

Visiting Cincinnati Childrens.

Cincinnati Children’s has primary care services at locations throughout Greater Cincinnati.