Clinical Reference Systems: Pediatric Advisor 10.0
Canker Sores (Mouth Ulcers)
- painful shallow ulcers (sores) in the lining of the
mouth, usually on the inside of lips, inside of cheeks,
- no fever.
The exact cause of canker sores is not known. Some may
result from prolonged contact with food that gets stuck in
the teeth. Others may be due to forgotten injuries from
toothbrushes, toothpicks, rough foods (such as corn chips),
hot foods, or self-biting.
Herpes simplex causes recurrent fever blisters on the outer
lip but does not cause recurrent canker sores on the inside of
The white color of canker sores is the normal color of
healing tissue in the mouth. The sores clear up in 1 to
2 weeks. Once they begin, no treatment can speed up the
- Pain relief
To reduce the pain, your child can swish 1 teaspoon of
an antacid solution in his or her mouth for several
minutes. For very young children, put a half teaspoon
of antacid solution directly on canker sores after
meals. A child over age 4 with just one sore can put an
antacid tablet on the sore and let it dissolve. Do this
three or four times a day. Give acetaminophen or
ibuprofen as needed for pain (especially at bedtime).
Offer a soft, bland diet to reduce the pain. Cold
drinks and milkshakes are especially good. Avoid giving
your child salty foods, citrus fruits, and foods that
need much chewing. Encourage your child to drink
favorite fluids to prevent dehydration. For very young
children, give fluids by cup rather than from a bottle
because the nipple can increase the pain.
Canker sores tend to recur in some people. Good
attention to toothbrushing after meals may prevent some
sores. Be careful with toothpicks and rough foods.
Try to identify any foods that might be causing the
ulcers. Were tomato, citrus fruit, peppermint, cinnamon,
nuts, or shellfish eaten within the last day? If you
find a food that you think may be causing the problem,
don't let your child eat the food for 2 weeks and then
offer it again to see whether your child gets canker
sores from it. If the canker sores do come back, your
child should never eat that food.
CALL YOUR CHILD'S PHYSICIAN DURING OFFICE HOURS IF:
- The pain becomes severe.
- Your child can't drink enough fluids.
- The sores last longer than 2 weeks.
- You feel your child is getting worse.