Canker sores and cold sores (fever blisters) are a real "pain
in the mouth" for children. Although they are harmless, during a typical episode the
child is uncomfortable and usually experiences trouble eating, drinking, and sleeping.
Canker sores, medically known as "aphthous stomatitis" (from the Greek word
aphtha or ulceration), resemble mini-moon craters, with a red rim surrounding a white or
yellowish center. These mouth ulcers, usually the size of a paper punch, are found on the
membranes inside the lips, floor of the mouth, inner cheeks, and tongue. Aphthous
stomatitis is very common - one out of two children will have at least one episode in
What causes these sores remains a medical mystery. Genetics may
play a role, since vulnerability to canker sores runs in families. Current studies suggest
many factors may be involved. The most popular theory is that the ulcers result from an
abnormal immune reaction to the mouth’s normal bacteria. Since adolescents and
college students seem more prone to developing aphthous ulcers around exam time, stress
may also be a factor. In addition, canker sores occasionally develop following minor
trauma inside the mouth, such as a slip of the toothbrush or a scrape from a potato chip.
Canker sores are not contagious and heal on their own in one to
two weeks. While there is no way to prevent canker some measures will help. Parents should
instruct their children not to bite the inside of the mouth or lips and avoid eating or
drinking scalding hot foods. If the child is prone to this condition, certain foods such
as cherries, plums, pineapples, tomato products, citrus juices should be avoided.
A cold sore, on the other hand, usually begins as a dime-sized
spot outside the mouth on the child’s lips and is less circular than canker sores.
When they form inside the mouth, cold sores are limited to the gums and roof of the mouth.
These painful lesions resemble chickenpox-, occurring singly or on clusters, usually
appearing on only one side of the mouth. The many small ulcers then rupture to form one
large blister, which usually swells up, ruptures, and then slowly oozes fluid that dries
to a scabby crust. The initial infection may be accompanied by fever, swollen lymph nodes,
and fatigue. Unlike canker sores, cold sores have a known cause--the herpes simplex type 1
virus. Do not be startled by the word "herpes." The herpes virus that causes
cold sores is much different and separate from the herpes virus that causes genital sores.
After recovering from a bout of cold sores, the herpes virus
quietly sets up a permanent home in the child’s nerve cells. From time to time, the
infection is reactivated and erupts into a typical cold sore. Fever, illness, cold wind or
hot sunlight can occasionally stir up the herpes virus.
Another virus responsible for ulcerative lesions in a child’s
mouth is the Coxsackie virus A16. This infection causes small, water blisters and red
spots in the front part of the mouth but the gums are usually not involved. In addition,
the child usually has similar sores on the hands and feet, therefore the name "Hand,
Foot, and Mouth Disease." This illness is quite contagious and most parents will know
of another child who has the same infection when their child is sick. Since the illness is
harmless and resolves in 7-10 days, most experts feel the child can go back to school when
the fever returns to normal.
A different Coxsackie virus causes "Herpangina," an
infection that causes an abrupt onset of fever, sore throat, and vomiting, as well as cold
sores in the back of the throat similar to those seen in "Hand, Foot, and Mouth
Whatever the cause, a child with cold sores or canker sores is
usually quite miserable. To make matters worse, antibiotics will not help either
condition. However, there are things parents can do to ease their youngster’s
1. Encourage fluids to prevent dehydration. The best tolerated are
milk, liquid Jell-O, ice cream, pudding, and milkshakes. Infants should use a glass
instead of the bottle and older children will find drinking through a straw easier. Offer
the youngster only cold foods and avoid things that are either hot (both in temperature
and spiciness!) or need to be chewed.
2. Apply 2% hydrogen peroxide with a cotton applicator to any
sores on the gums. Older children can rinse with a mouthwash such as Cepacol. Avoid
antiseptic mouthwashes or antiseptic throat lozenges, since they will irritate the ulcers.
3. Check with the child’s doctor about a topical medication.
Some physicians will prescribe an anesthetic gel that will temporarily ease the pain so
that the child can eat and sleep. If the youngster’s lips are dry and cracked, coat
them with a lubricant such as petroleum jelly.
4. Watch for signs of dehydration, such as sunken eyes, absence of
saliva in the mouth, urinating less, or extreme drowsiness or listlessness. Daily weights
and monitoring fluid intake are a good way parents can watch for dehydration.
6. Avoid transmission of cold sores by boiling eating utensils and
anything else that meets the child’s mouth.
7. Call the child’s physician to see what medication can be
given for pain, particularly useful before eating and sleeping. Usually, acetaminophen
(Tylenol) will be sufficient, but occasionally stronger medication, such as ibuprofen, may
8. For older children and adolescents, dentists recommend the
following homemade remedy. Apply a mixture of equal amounts of Maalox and Benadryl to the
canker sore using a cotton swab. Make sure the child does not swallow this mixture.
9. If toothbrushing becomes too painful, have the child rinse
their mouth with water after meals.
10. If the canker sore or cold sore does not go away within seven
to ten days, consult your child’s physician or dentist.