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Mouth Sores in Children: Understand What May Be Causing Them

If your child has mouth sores, mouth ulcers, or painful spots inside the mouth, get clear next-step guidance based on their symptoms, how long the sores have been present, and whether they keep coming back.

Answer a few questions about your child’s mouth sores

Tell us whether the sores are few or frequent, mild or very painful, and we’ll provide personalized guidance on possible causes, home care, and when to seek medical care.

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Why children get mouth sores

Mouth sores in children can happen for several reasons. Common causes include canker sores, irritation from biting the cheek or tongue, braces or dental appliances, viral illnesses, and less often nutritional issues or other medical conditions. Some child mouth sores heal on their own within 1 to 2 weeks, while others are more painful, appear in clusters, or return often. Looking at the pattern of sores, your child’s age, pain level, eating and drinking, and any fever or rash can help narrow down what may be going on.

Common signs parents notice

Pain with eating or drinking

Painful mouth sores in a child may make them avoid acidic, salty, crunchy, or hot foods. Younger children may drool, refuse bottles, or seem fussy at meals.

Small round sores or ulcers

Mouth ulcers in children often look like shallow white, yellow, or gray sores with a red border on the inside of the lips, cheeks, gums, or tongue.

Sores that come back

If your child has sores in the mouth again and again, it may point to recurring canker sores, irritation, or another trigger worth discussing with a clinician.

What causes mouth sores in kids

Canker sores

These are a common cause of mouth sores in kids symptoms. They are not contagious and usually appear as one or more painful ulcers inside the mouth.

Irritation or injury

A bitten cheek, rough tooth edge, braces, or aggressive brushing can lead to child mouth sores that are tender but often improve as the area heals.

Illness or infection

Some viral infections can cause several sores at once, sometimes along with fever, swollen gums, rash, or low appetite.

How to help heal mouth sores in children

Offer gentle foods and fluids

Cool water, milk, smoothies, yogurt, applesauce, and other soft foods may be easier to tolerate. Avoid citrus, spicy foods, and salty snacks if they sting.

Protect the sore from more irritation

Use a soft toothbrush and encourage your child not to pick at the area. If braces or a sharp tooth seem involved, dental follow-up may help.

Watch for dehydration or worsening pain

If your toddler has mouth sores and is drinking less, has fewer wet diapers, or seems unusually sleepy, they may need prompt medical advice.

When mouth sores need medical attention

Seek medical care sooner if your child has very painful sores, trouble drinking, signs of dehydration, a high fever, swollen gums, a widespread rash, sores outside the mouth, or sores lasting longer than about 2 weeks. Recurrent mouth sores in children also deserve a closer look, especially if they are frequent, severe, or linked with weight loss, stomach symptoms, or poor growth.

Frequently Asked Questions

What causes mouth sores in kids most often?

The most common causes are canker sores, minor injury from biting the mouth, irritation from dental appliances, and viral illnesses. The number of sores, where they are located, and whether your child has fever or other symptoms can help point to the cause.

How can I treat mouth sores in children at home?

Focus on comfort and hydration. Offer cool drinks and soft foods, avoid acidic or spicy foods, and use a soft toothbrush. If your child is in significant pain or not drinking well, contact a healthcare professional for guidance.

Are mouth ulcers in children contagious?

Canker sores are not contagious. However, some infections that cause sores in or around the mouth can spread to others. If your child also has fever, blisters, or sores on the lips or skin, infection may be more likely.

When should I worry about painful mouth sores in my child?

Get medical advice if the sores are very painful, your child cannot drink, there are signs of dehydration, the sores keep coming back, or they have not healed after about 2 weeks.

Why does my toddler keep getting mouth sores?

Recurring mouth sores can happen with repeated irritation, canker sores, or less commonly an underlying health issue. If your child has frequent episodes, a clinician can help review patterns, triggers, and whether further evaluation is needed.

Get personalized guidance for your child’s mouth sores

Answer a few questions to better understand possible causes of your child’s mouth sores, what home care may help, and when it may be time to seek medical care.

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