Canker Sores

Topic Overview

What is a canker sore?

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. Unlike cold sores, you cannot spread canker sores to other people. See a picture of canker sores.

Anyone can get a canker sore but women, teenagers, and young adults have them more often. People usually get their first canker sore between the ages of 10 and 40. 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 may also develop when you:

  • Are stressed or tired.
  • Have your menstrual cycle, if you are a woman.
  • Hurt your mouth, such as biting your lip.
  • Have braces on your teeth.
  • Have food allergies. Eating foods that you are allergic to may cause you to get a canker sore.
  • Eat or drink food or juice that has a lot of acid, such as orange juice.
  • Do not get enough vitamins or minerals in your diet, such as iron.

What are the symptoms?

The main 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 a physical exam by looking in your mouth to diagnose the canker sores.

How is it treated?

You do 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 sores:

  • 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.
  • 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 water.
  • Buy an over-the-counter medicine such as Orabase, Anbesol, or milk of magnesia 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.
  • Take a pain reliever, such as nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin (such as Bayer), ibuprofen (such as Advil), or naproxen sodium (such as Aleve). Do not give aspirin to anyone younger than 20 because of the risk of Reye syndrome.

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 the 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 prescribe steroid cream (triamcinolone or fluocinonide) or paste (amlexanox) 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 your life.

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

Organizations

American Dental Association
211 East Chicago Avenue
Chicago, IL  60611-2678
Phone: (312) 440-2500
Web Address: www.ada.org
 

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 Teens
10140 Centurion Parkway North
Jacksonville, FL  32256
Phone: (904) 697-4100
Fax: (904) 697-4125
Web Address: www.kidshealth.org
 

This Web site 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 Web site 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 e-mails about your area of interest.


References

Other Works Consulted

  • Allen CM (2007). Aphthous ulceration (canker sore) section of Diseases of the mouth. In RE Rakel, ET Bope, eds., Conn's Current Therapy 2007, p. 991. Philadelphia: Saunders Elsevier.
  • Beaudreau RW (2004). Soft tissue lesions of the oral cavity section of Oral and dental emergencies. In JE Tintinalli et al., eds., Emergency Medicine: A Comprehensive Study Guide, 6th ed., pp. 1486–1487. New York: McGraw-Hill.
  • Blair EA, Eibling DE (2001). Systemic, autoimmune, and allergic conditions section of Mucosal lesions of the oral cavity, tongue, and oropharynx. In KH Calhoun et al., eds., Expert Guide to Otolaryngology, pp. 240–246. Philadelphia: American College of Physicians.
  • Schindler J, et al. (2008). Intraoral ulcerative lesions section of Ear, nose, and throat. In SJ McPhee et al., eds., Current Medical Diagnosis and Treatment, 47th ed., pp. 190–191. New York: McGraw-Hill Medical.
  • Smeltzer SC, et al., eds. (2008). Management of patients with oral and esophageal disorders. In Brunner and Suddarth's Textbook of Medical–Surgical Nursing, 11th ed., pp. 1143–1144. Philadelphia: Lippincott Williams and Wilkins.

Credits

Author Maria G. Essig, MS, ELS
Editor Susan Van Houten, RN, BSN, MBA
Associate Editor Pat Truman, MATC
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer Steven K. Patterson, BS, DDS, MPH - Dentistry
Last Updated October 9, 2008

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