Canker Sores (Aphthous Ulcers) in Children

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This content is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician with any questions you have regarding a medical condition. Your provider will offer referrals or treatment plans based on your specific condition or diagnosis.

What are canker sores in children?

Canker sores (aphthous ulcers) are small sores inside the mouth. They are often found inside the lips, on the back part of the roof of the mouth (soft palate), on the cheeks, or on the tongue.

What causes canker sores in a child?

Experts don't know the exact cause. But many factors are thought to play a role with the development of canker sores. These are:

  • Weakened immune system

  • Sensitivities to food, such as coffee, chocolate, cheese, nuts, and citrus fruits

  • Stress

  • Viruses and bacteria

  • Mouth injury

  • Poor nutrition and vitamin deficiencies

  • Certain medicines

  • Irritation from orthodontic braces

  • Hormonal changes

Canker sores are often first seen in children and teens between ages 10 and 19. For about 3 in 10 children affected, canker sores come back for years after the first outbreak. They can’t be spread from one child to another.

Canker sores that keep coming back may be linked to celiac disease, inflammatory bowel disease, or HIV infection.

What are the symptoms of canker sores in a child?

Each child may feel symptoms a bit differently. Below are the most common symptoms of aphthous stomatitis:

  • Painful sores in the mouth, often inside the lips, on the cheeks, or on the tongue

  • Sores that are white or gray with a red border

  • Trouble eating or talking because of the sores

  • No fever (in most cases)

Canker sores often heal in 7 to 14 days. They tend to come back.

How are canker sores diagnosed in a child?

Your child’s healthcare provider can often make a diagnosis with a full health history and a physical exam. But your child may also need these tests to rule out other causes:

  • Blood tests

  • Cultures of the sores

  • Biopsy of the sore (taking a small piece of tissue from the sore and checking the cells under a microscope)

How are canker sores treated in a child?

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

The goal of treatment is to help ease symptoms. Treatment may include:

  • Drinking more fluids

  • Taking acetaminophen for any fever or pain

  • Getting correct oral hygiene

  • Using medicines on the skin to help ease the pain of the sores

  • Using mouth rinses to help with the pain

Your child may feel better by not eating spicy, salty, or acidic foods. These foods may make the mouth more irritated.

When should I call my child’s healthcare provider?

Call your child’s healthcare provider if the sores:

  • Are very painful

  • Last more than a few weeks

  • Are very large in size

  • Keep coming back

Key points about canker sores in children

  • Canker sores are small white or gray sores with a red border that are seen in the mouth.

  • They are often found inside the lips, on the cheeks, or on the tongue.

  • Experts don't know the exact cause. But they may be linked to things such as food allergies, stress, poor nutrition, or certain medicines.

  • The sores are different from other sores. They are often diagnosed simply with a physical exam.

  • Treatment may include oral medicine or medicine for the skin to ease pain. Antibiotics may be prescribed for secondary infections.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

  • Know the reason for the visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.

  • Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are and when they should be reported.

  • Ask if your child’s condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if your child does not take the medicine or have the test or procedure.

  • If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your child’s healthcare provider after office hours, and on weekends and holidays. This is important if your child becomes ill and you have questions or need advice.