A canker sore is a shallow sore shaped like a crater
(ulcer) on your tongue or on the inside of your lip or cheek. Canker sores have
a red border and a white or yellow center. They may be painful and can make it
hard to talk and eat. You may have one or more than one canker sore at a time.
cold sores, you cannot spread canker sores to other
people. See a picture of
Anyone can get a canker sore, but women, teens,
and young adults have them more often. Most people have canker sores at some time
in their lives, and some people have them regularly.
What causes a canker sore?
The cause of canker sores is unknown,
but they tend to run in families. Canker sores are not contagious.
Canker sores may also develop when
Are stressed or tired.
Have your menstrual cycle,
if you are a woman.
Hurt your mouth, such as biting your
Have braces on your teeth.
Have food allergies.
Eating foods that you are allergic to may cause you to get a canker
Eat or drink food or juice that has a lot of acid, such as
Do not get enough vitamins or minerals in your diet,
such as iron, vitamin B12, and folic acid..
What are the symptoms?
symptom of a canker sore is getting a shallow ulcer on your tongue or on the
inside of your lip or cheek. The sore may be large or small, and it will have a
red border and a white or yellow center. You might have more than one canker
sore at a time.
Canker sores usually begin with a burning or
tingling feeling. They may be swollen and painful. Having a canker sore can
make it hard to talk or eat.
Canker sores may hurt for 7 to 10
days. Minor canker sores heal completely in 1 to 3 weeks, but major canker
sores can take up to 6 weeks to heal. Some people get another canker sore after
the first sore has healed. Most canker sores heal without a scar.
How is a canker sore diagnosed?
If you see your
doctor or dentist about the pain caused by your canker sores, he or she will do
physical exam by looking in your mouth to diagnose the
How is it treated?
not need to see a doctor for most
canker sores. They will get better on their own. There
are many things you can try at home to relieve the pain caused by your canker
Eat soft, bland foods that are easy to swallow, such as
yogurt or cream soup. Cut your food into small pieces or mash or puree it.
Avoid coffee, chocolate, spicy or salty foods, citrus fruits or juices, nuts,
seeds, and tomatoes.
Drink cold fluids, such as water or iced tea,
or eat Popsicles. Sometimes fluid touching the canker sore can cause a stinging
pain. Use a straw so the fluid doesn't touch the canker sore. Hold ice on the
canker sore until it is numb.
Carefully brush your teeth so you don't touch the sore with the toothbrush bristles.
Rinse your mouth with salt water. To
make a salt water rinse, dissolve 1 tsp (5 g) of salt in 1 cup (250 mL) of warm
Buy an over-the-counter medicine, such as Anbesol,
milk of magnesia, or Orabase, to put on your canker sores. Use a cotton swab to apply the
medicine. Put it on your sores 3 to 4 times a day.
If your canker sores do
not feel better after trying these steps at home for 2 weeks, you may need to
see your doctor or dentist. He or she may recommend medicines that will help
relieve pain caused by your canker sores. Usually these medicines are swished or
gargled in your mouth, or they are painted on the sore. Your doctor may
steroid cream or paste to rub on your canker sore and/or a prescription mouthwash to use.
Talk to your doctor if you have a fever, have trouble swallowing,
or if your canker sores keep coming back. You may have another problem that is
causing your symptoms.
How can canker sores be prevented?
Most of the time the cause of canker sores is
unknown. Unless you know what causes your canker sores, you cannot prevent them
from happening. If you do know what causes your canker sores, you can help
prevent them by avoiding what you know causes them. For example, if you have
gotten canker sores in the past from hurting the inside of your mouth, you
might help prevent them by chewing your food slowly and carefully, trying not
to talk and chew at the same time, and using a soft-bristled toothbrush when
you brush your teeth.
If you have gotten canker sores in the past
by eating foods that have a lot of acid (such as citrus fruits or tomatoes) and
sharp or harsh foods (such as bread crusts, corn chips, or potato chips), it
might help to avoid these. Other ways that might help to prevent canker sores
include limiting your use of alcohol and tobacco and controlling the stress in
In general, it is important to get enough vitamins and
minerals in your diet, like folic acid, vitamin B12, zinc, and iron.
Other Places To Get Help
American Academy of Family
P.O. Box 11210
Shawnee Mission, KS 66207-1210
The website FamilyDoctor.org is sponsored by the American Academy of Family Physicians. It offers information on adult and child health conditions and healthy living. There are topics on medicines, doctor visits, physical and mental health issues, parenting, and more.
American Dental Association
211 East Chicago Avenue
Chicago, IL 60611-2678
The American Dental Association (ADA), the professional
membership organization of practicing dentists, provides information about oral
health care for children and adults. The ADA can also help you find a dentist
in your area.
KidsHealth for Parents, Children, and
Nemours Home Office
10140 Centurion Parkway
Jacksonville, FL 32256
This website is sponsored by the Nemours Foundation. It
has a wide range of information about children's health—from allergies and
diseases to normal growth and development (birth to adolescence). This website
offers separate areas for kids, teens, and parents, each providing
age-appropriate information that the child or parent can understand. You can
sign up to get weekly emails about your area of interest.
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Woo SB (2012). Biology and pathology of the oral cavity. In LA Goldman et al., eds., Fitzpatrick's Dermatology in General Medicine, 8th ed., vol. 1, pp. 827–852. New York: McGraw-Hill.
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