Canker Sores on Baby's Tongue

Canker sores are mouth ulcers that can be particularly painful when they are touched. Although the Nemours Foundation says that about one in every five people regularly develops canker sores, children under age 10 rarely develop them 2. However, if you notice a sore on your baby’s tongue that seems to become irritated when he eats or when his teeth are being cleaned, he may have a canker sore.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Canker sores, also known as aphthous ulcers, are small sores that may arise on the tongue, cheek, lips or throat. According to the Nemours Foundation, canker sores aren’t fever blisters or cold sores, which are caused by the herpes simplex virus and found outside the mouth and inside the nostrils. Because canker sores don’t appear to be caused by a virus, they aren’t contagious.

Signs and Symptoms

A canker sore in your baby’s mouth may appear as a slightly round white or yellow open sore that is surrounded by a red “halo,” according to 3. A canker sore can be as large as 1 inch across, although it may be significantly smaller. It also often arises by itself, although it may appear among others in a cluster. Your baby may feel slight tingling before a canker sore is about to erupt, although he likely won’t be able to verbalize his feelings. Once his canker sore is present, however, he may be in discomfort and potentially act listless and have a fever and swollen lymph nodes.

  • A canker sore in your baby’s mouth may appear as a slightly round white or yellow open sore that is surrounded by a red “halo,” according to 3.


4-Month-Baby Diet

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Your baby’s canker sore may arise as a result of trauma to his mouth such as biting his tongue or be related to a food allergy, infection or dietary deficiency such as a lack of vitamin B12, zinc, iron or folic acid, according to 3. Canker sores also run in families 3. According to the Nemours Foundation, your child has a 90 percent chance of eventually developing canker sores if you are prone to them 1.


Your baby generally won’t require any specific medication for a canker sore on her tongue. The pain should diminish within a few days and the canker sore should subside on its own within a week to 10 days, according to 3. However, to prevent adding unnecessary discomfort, avoid giving your baby any aggravating citrus or spicy foods. Also consider giving him a cold, wet washcloth to gum on. If your baby still seems to be in pain, recommends mixing 1 part hydrogen peroxide and 1 part water and dabbing it onto your baby’s sore with a swab, then following it with a dab of milk of magnesia three to four times each day 3. Another way to reduce your baby’s discomfort is to give him a baby dose of an over-the-counter pain reliever such as ibuprofen or acetaminophen.

When to See a Doctor

A Canker Sore in a Toddler

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If you’re not positive that the sore on your baby’s tongue is a canker sore, or if it persists beyond a couple of weeks, schedule a doctor’s appointment for a professional diagnosis. A doctor will also be able to offer you advice on quelling a fever and keeping your baby properly hydrated if the canker sore prevents him from drinking enough.