Canker Sores in Kids: What Parents Should Know

What Are Canker Sores?

Canker sores (also called aphthous ulcers) are small, shallow sores that develop inside the mouth—often on the cheeks, lips, tongue, or gums. They usually appear as round or oval white or yellow spots with a red border.

Unlike cold sores, canker sores are not contagious and do not occur on the outside of the lips.

What Causes Canker Sores in Children?

There isn’t always one clear cause, but common triggers include:

• Minor mouth injuries (biting the cheek, braces, or rough brushing)

• Stress or fatigue

• Certain foods (especially acidic or spicy foods)

• Vitamin deficiencies (such as iron or B vitamins)

• Sensitivity to toothpaste with sodium lauryl sulfate (SLS)

• A weakened immune system

Signs Your Child Has a Canker Sore

You may notice your child:

• Complaining of mouth pain or sensitivity

• Avoiding certain foods

• Having trouble brushing their teeth

• Pointing to a sore spot inside their mouth

Most canker sores heal within 7–14 days without treatment.

How to Help Your Child Feel Better

While you can’t always prevent canker sores, you can help reduce discomfort and support healing:

• Encourage gentle brushing with a soft-bristled toothbrush

• Avoid spicy, salty, or acidic foods while the sore heals

• Rinse with warm salt water (for older kids who can swish safely)

• Use a pediatric-safe topical gel if recommended by your dentist

• Make sure your child stays hydrated

When Should You See a Dentist?

Most canker sores are harmless, but you should contact your pediatric dentist if:

• The sore lasts longer than two weeks

• Your child gets frequent or unusually large sores

• The pain interferes with eating or drinking

• You notice signs of infection or fever

At Inspire Kids Dental, we’re always happy to take a look and make sure everything is healing properly.

Can Canker Sores Be Prevented?

While not all canker sores are preventable, these tips may help reduce how often they occur:

• Maintain good oral hygiene

• Use toothpaste made for sensitive mouths

• Encourage a balanced diet with essential vitamins

• Address dental issues like sharp edges or orthodontic irritation

We’re Here to Help

Canker sores can be uncomfortable, but they’re usually nothing to worry about. If you have concerns about your child’s oral health—or if something just doesn’t seem right—our team at Inspire Kids Dental is here to help keep little smiles healthy and pain-free.

Learn more about us and what we can do for you on our About Us and Services page! Have questions about out emergency services? Visit our Dental Emergencies page here.