Stomatitis (Child)

Stomatitis is swelling (inflammation) inside the mouth and on the lips. It can cause open sores (canker sores), redness, and pain. It occurs on the inside of the cheeks or on the tongue, lips, or gums. Stomatitis is more common in children. But it can occur at any age.


There are many causes of stomatitis. The most common is viral infections. Other common causes are:

  • Injury or irritation of the mouth lining

  • Fungal or bacterial infections

  • Using tobacco

  • Irritating foods such as citrus fruit or spices

  • Irritating chemicals such as toothpaste or mouthwash

  • Lack of certain vitamins, including vitamins B and C

  • A weakened immune system


Stomatitis can cause a variety of symptoms, including:

  • Redness inside the mouth

  • Sores (ulcers) in the mouth

  • Pain or burning

  • Swelling

  • Fever


For a viral infection, usually only the symptoms are treated. Antibiotics do not kill viruses. They are not advised for this condition. A viral infection should go away within 7 to 10 days.

Home care

  • Use a local numbing solution for pain relief. Ask the pharmacist for suggestions on which brand and strength is best for your child. You may apply this directly to the sores with a cotton swab or with your finger. Use the numbing solution just before meals if eating is a problem.

  • Older children may rinse their mouth with warm saltwater (½ teaspoon of salt in 1 glass of warm water). Make sure they spit the rinse out and don’t swallow it.

  • Feed your child a soft diet, along with plenty of fluids to prevent dehydration. If your child doesn't want to eat solid foods, it's OK for a few days, as long as he or she drinks lots of fluids. Cool drinks and frozen treats are soothing. Don't give your child citrus juices such as orange juice or lemonade or salty or spicy foods. These may cause more pain in the mouth.

  • Follow the healthcare provider's instructions on using over-the-counter pain medicines such as acetaminophen for fever, fussiness, or pain. In babies older than 6 months, you may use children's ibuprofen. Talk with the provider before using these medicines if your child has chronic liver or kidney disease or has ever had a stomach ulcer or digestive bleeding. Don’t give aspirin to a child younger than age 19 unless directed by your child’s provider. Taking aspirin can put your child at risk for Reye syndrome. This is a rare but very serious disorder. It most often affects the brain and the liver.

  • Children should stay home until their fever is gone and they are eating and drinking well.

Follow-up care

Follow up with your child’s healthcare provider, or as advised.

If a culture was done, you will be told if the treatment needs to be changed. You can call as directed for the results.

Call 911

Call 911 if your child has any of these:

  • Trouble breathing

  • Inability to swallow

  • Extremes drowsiness or trouble waking up

  • Fainting or loss of consciousness

  • Rapid heart rate

  • Seizure

  • Stiff neck

When to seek medical advice

For a usually healthy child, call your child's healthcare provider right away if any of these occur:

  • Your child has a fever (see Fever and children, below).

  • Your child can't eat or drink due to mouth pain.

  • Your child shows unusual fussiness, drowsiness, or confusion.

  • Your child shows symptoms of dehydration. This may include no wet diapers for 8 hours, no tears when crying, sunken eyes, or a dry mouth.

Fever and children

Use a digital thermometer to check your child’s temperature. Don’t use a mercury thermometer. There are different kinds and uses of digital thermometers. They include:

  • Rectal. For children younger than 3 years, a rectal temperature is the most accurate.

  • Forehead (temporal). This works for children age 3 months and older. If a child under 3 months old has signs of illness, this can be used for a first pass. The provider may want to confirm with a rectal temperature.

  • Ear (tympanic). Ear temperatures are accurate after 6 months of age, but not before.

  • Armpit (axillary). This is the least reliable but may be used for a first pass to check a child of any age with signs of illness. The provider may want to confirm with a rectal temperature.

  • Mouth (oral). Don’t use a thermometer in your child’s mouth until he or she is at least 4 years old.

Use the rectal thermometer with care. Follow the product maker’s directions for correct use. Insert it gently. Label it and make sure it’s not used in the mouth. It may pass on germs from the stool. If you don’t feel OK using a rectal thermometer, ask the healthcare provider what type to use instead. When you talk with any healthcare provider about your child’s fever, tell him or her which type you used.

Below are guidelines to know if your young child has a fever. Your child’s healthcare provider may give you different numbers for your child. Follow your provider’s specific instructions.

Fever readings for a baby under 3 months old:

  • First, ask your child’s healthcare provider how you should take the temperature.

  • Rectal or forehead: 100.4°F (38°C) or higher

  • Armpit: 99°F (37.2°C) or higher

Fever readings for a child age 3 months to 36 months (3 years):

  • Rectal, forehead, or ear: 102°F (38.9°C) or higher

  • Armpit: 101°F (38.3°C) or higher

Call the healthcare provider in these cases:

  • Repeated temperature of 104°F (40°C) or higher in a child of any age

  • Fever of 100.4 or higher in baby younger than 3 months

  • Fever that lasts more than 24 hours in a child under age 2

  • Fever that lasts for 3 days in a child age 2 or older

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