About Us | Privacy | Site Map
Font Size
A
A
A


Canker Sores

Canker Sore Overview

Canker sores, also known as aphthous stomatitis, are among the most common causes of painful sores in the mouth.

  • From 20%-40% of the U.S. population have them at some point in their lives.

  • The peak incidence occurs among people in adolescence and young adulthood. They become less frequent as we get older.

  • They are not contagious.

  • Canker sores are not the same thing as cold sores. Cold sores ("fever blisters") occur on the outer lip, whereas canker sores are found inside the mouth.


Canker Sore Causes

No one knows what causes canker sores. The vast majority of people who develop canker sores do not have another problem as the cause.

  • The disease is suspected to result from a reaction of the immune system.

  • Additional causative factors may include the following:

    • bacterial infections

    • hormonal disorders

    • stress

    • trauma

    • heredity

    • drugs (including anti-inflammatory drugs, such as ibuprofen, and beta-blockers, such as atenolol)

    • food allergies or sensitivities (chocolate, tomatoes, nuts, and acidic foods such as pineapple)

    • toothpastes containing sodium lauryl sulfate

    • deficiencies of iron, folic acid, or vitamin B12
  • Recurrent canker sores have been associated with inflammatory bowel diseases, such as Crohn disease and ulcerative colitis. In these cases, the development of canker sores may signal a flare-up of the bowel disease.

  • Celiac, or abdominal, sprue, a disease of the intestines caused by sensitivity to gluten, causes malabsorption and is associated with development of canker sores. Gluten refers to a group of proteins found in wheat, barley, and rye.

  • Behçet disease is a condition characterized by canker sores, genital sores that resemble canker sores, and inflammation of the eye.

  • Infection with the AIDS virus also has been associated with canker sores.

  • It is a common misconception that canker sores are a form of herpes infection. This is not the case.

Canker Sore Symptoms

Canker sores occur in several forms. They can involve any area of the mouth except for the gums, lips, and hard palate.

  • Minor canker sores (which account for the majority of aphthous ulcers) are oval and less than 10 mm (1/3 inch) across. Most are 2-3 mm with a white center. They are painful but clear up within three to 14 days without scarring. It is unusual for them to become infected.

  • Major canker sores consist of deep ulcers measuring greater than 1 cm (1/3 inch). These ulcers, which are very painful, have irregular margins and often last for three to six weeks. They tend to heal with extensive scarring.

  • A third form of canker sores, termed "herpetiform," resemble herpes infections and consist of many small shallow punched-out lesions, pinhead-sized (1-3 mm) in diameter, or less than one-tenth of an inch. Clusters of these sores may merge together to form large irregular ulcers. They last from seven to 10 days.

  • Canker sores commonly come back. Some people have a few outbreaks a year, while others can have them almost all the time.


Next: When to Seek Medical Care »

Viewer Comments & Reviews

Canker Sores - Effective Treatments

The eMedicineHealth physician editors ask:

Please describe what treatments have been effective for your canker sores.

Anonymously share your comment to help others. Viewer Comments FAQs
See 9 Viewer Comments & Reviews

Submit Your Review


Printer-Friendly Format  |  Email to a Friend


Women's Health

Find out what women really need.

Are you Depressed? Find Out Now


Canker Sores

Cold Sores Overview

Cold sores are small, painful, fluid-filled blisters or sores that appear on the lips, mouth, or nose that are caused by a virus. The sores can be painful and usually last a few days. Unlike most viral infections, the cold sore virus is not completely eliminated by the body defenses. For this reason, cold sores often recur.

Cold Sore Causes

The virus that causes cold sores is known as the herpes simplex virus (HSV). There are two types of HSV, type I and type II. Cold sores are usually caused by type I. Herpes simplex infections are contagious. The virus is spread from person to person by kissing or other close contact with sores or even from contact with apparently normal skin that is shedding the virus. Infected saliva is also a means of transmitting the virus. People are most contagious when they have active blister-like sores. Once the blisters have dried and crusted over (within a few days...

Read the Cold Sores article »


Read What Your Physician is Reading on eMedicine

Aphthous Ulcers »

Recurrent aphthous stomatitis (RAS) is a common condition, restricted to the mouth, that typically starts in childhood or adolescence as recurrent small, round, or ovoid ulcers with circumscribed margins, erythematous haloes, and yellow or gray floors.

Read More on eMedicine »

Medical Dictionary