Home > Health Library > Canker Sores
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.
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
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.
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
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
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.
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 Works Consulted
Bruch JM, Treister NS (2010). Aphthous stomatitis (canker sores). In Clinical Oral Medicine and Pathology, pp. 53–56. New York: Humana Press-Springer.
Coleman GC (2015). Diseases of the mouth. In ET Bope et al., eds., Conn's Current Therapy 2015, pp. 249–255. Philadelphia: Saunders.
Quinn KL (2010). Management of patients with oral and esophageal disorders. In SC Smeltzer et al., eds., Brunner and Suddarth's Textbook of Medical-Surgical Nursing, 12th ed., pp. 999–1000. Philadelphia: Lippincott Williams and Wilkins.
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.
ByHealthwise StaffPrimary Medical ReviewerKathleen Romito, MD - Family MedicineAdam Husney, MD - Family MedicineE. Gregory Thompson, MD - Internal MedicineSpecialist Medical ReviewerArden Christen, DDS, MSD, MA, FACD - Dentistry
Current as ofMarch 30, 2016
Current as of:
March 30, 2016
Kathleen Romito, MD - Family Medicine & Adam Husney, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine & Arden Christen, DDS, MSD, MA, FACD - Dentistry
To learn more about Healthwise, visit Healthwise.org.
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