Canker sores and cold sores number among Americans' most common mouth complaints, according to the National Institute of Dental and Craniofacial Research. Although canker sores and cold sores aren't serious, they are uncomfortable, annoying and unattractive. The American Dental Association recommends seeing a dentist who can confirm the diagnosis and rule out other, more serious causes of mouth complaints.
Features
The American Dental Association describes canker sores as flat lesions of variable size with a white, yellow or gray center and a red border that might be slightly raised. Cold sores are blisters that are 1 to 2 mm and are filled with clear or cloudy yellow fluid. However, inside the mouth, says University of Washington Chair of Virology Dr. Lawrence Corey in the 2008 edition of "Harrison's Principles of Internal Medicine," the blisters rupture almost immediately, leaving behind a flat lesion that appears similar to a canker sore.
Time Frame
Canker sores and cold sores usually heal spontaneously within seven to 10 days, according to the American Dental Association. Lesions that last longer should be seen by a doctor or a dentist because persistent lesions may signal a complication, such as bacterial infections, or a different diagnosis, such as cancer.
Location
Ninety percent of cold sores develop on the lips, according to Northeastern Ohio University internist Dr. Christina Cernik in the 2008 edition of "Archives of Internal Medicine." Only about 5 percent occur inside the mouth. Those that do usually target the roof of the mouth, called the palate, while canker sores usually target the lining of the cheeks or the gums. People usually only develop cold sores inside the mouth during the first outbreak, Corey adds, so recurrent intraoral lesions usually mean canker sores.
Cause
According to the American Dental Association, most cases of cold sores are caused by the herpes simplex virus while doctors and dentists still don't know exactly what causes canker sores. Both sores can be triggered by fatigue, emotional stress, infections or local injuries from eating hard or sharp food or instruments used to perform dental work.
Treatment
Oral or topical prescription antiviral drugs significantly reduce the severity and duration of cold sores, according to Corey, but they have no effect on canker sores. For severe canker sores, the American Dental Association recommends oral or topical steroids such as prednisone. Over-the-counter medications such as oral acetaminophen or topical preparations of lidocaine, benzocaine, tetracaine, phenol or camphor can help relieve pain and irritation caused by either type of sore. Good oral hygiene, including antimicrobial mouthwashes can help prevent bacterial infections, according to the American Dental Association,
References
- National Institute of Dental and Craniofacial Research: Fever Blisters and Canker Sores
- Journal of the American Dental Association: For the Patient: Canker Sores and Cold Sores
- "Archives of Internal Medicine"; "The Treatment of Herpes Simplex Infections; C. Cernik et al.; 2008
- "Harrison's Principles of Internal Medicine, 23rd Edition"; A.S. Fauci et al.; 2008
