By Chris Woolston, M.S.
What are canker sores?
They're small, painful, crater-like nuisances that sprout on the tongue or on the inside of the cheeks. The sores are usually white, gray, or yellowish with a red rim and last up to two weeks. (Some people confuse them with cold sores, which form blisters instead of craters and usually show up on or around the lips.) Canker sores are most common in teenagers and women, but they can strike children as young as two.
What causes canker sores?
These simple sores are a real mystery. Nobody knows why they erupt, but several factors seem to set the stage for their arrival, including emotional stress, irritation from sour or spicy foods, or injury to the mouth's lining from toothbrushing, biting, hot liquids, or rough foods such as corn chips. If your child frequently gets sores, he may have a more deep-rooted problem such as a food allergy or a deficiency of vitamin B-12, folic acid, or iron.
Unlike cold sores, canker sores aren't caused by a virus or any other type of germ, and they can't spread from one person to another. So don't turn down a goodnight kiss just because your child has a canker sore. (Remember, the kiss supply will run awfully low in a few years!)
How can I treat them?
Minor canker sores usually don't need treatment, and usually clear up in a week or two. But you can take some steps to make the sores less painful and annoying. Have your child avoid spicy, sour, or rough-edged foods like corn chips that can irritate the sores. If he's old enough, have him rinse his mouth several times each day with a cup of warm water mixed with half a teaspoon of salt (don't let him swallow).
For younger children, apply a paste of baking soda and water directly on the sore after meals. You can also ease the pain with an over-the-counter salve, Zilactin, which contains tannic acid that will numb the sore; it stings terribly for a few minutes, though, so it's not a realistic option for young children. Ibuprofen or acetaminophen will also lessen pain from the sores. (Don't use aspirin in anyone under 20; it may cause Reye's syndrome, a rare but potentially life-threatening illness.)
A small amount of milk of magnesia dabbed on the sore a few times a day may help ease pain and promote healing. With luck, you might be able to coax your child into eating a dish of cold ice cream to numb the spot.
When should I call the doctor?
Schedule an appointment with your pediatrician if the sores last more than two weeks, the pain becomes severe, the canker sores are accompanied by a high fever or your child has trouble swallowing. Consult the doctor as well if the sores continually crop up, are very large, or extend onto the lips.
Your pediatrician may prescribe mouth rinses or topical pastes to help relieve pain and speed healing.
How can I prevent my child from getting canker sores?
Buy your child a soft-bristled toothbrush, and make sure he uses it at least twice each day. Give him toothpaste that doesn't contain sodium lauryl sulfate, a detergent that seems to promote the sores. Biotene Dry Mouth Toothpaste and Rembrandt Natural Toothpaste are two of the brands that don't contain the ingredient.
If your child has braces or other dental appliances, ask your dentist about special wax to cover sharp edges.
If your child is allergic to certain foods, make sure he avoids them. If canker sores are a chronic problem, your pediatrician may recommend a daily multivitamin to help boost your child's immune system.
U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health. NIH Publication No. 87-247: Fever Blisters and Canker Sores.
The Self-Care Advisor: The Essential Home Health Guide for You and Your Family. Time Life: 78-9.
Canker sore. Mayoclinic.com. January 31, 2008. http://www.mayoclinic.com/health/canker-sore/DS00354/DSECTION=treatments-and-drugs