Causes and Treatment of Canker Sores

Canker sores are mouth lesions that are typically white or yellow in the center, surrounded by an inflamed red ring. These ulcers more commonly occur in women than in men.

Cause of Canker Sores

Unlike cold sores (caused by herpes virus) or a syphilis cancre (caused by the bacterium Treponema pallidum), common canker sores are not directly caused by an infectious agent and are not contagious, but their appearance has been shown to be associated with viral infections, and a predisposition to develop canker sores tends to run in families.

In addition to viral triggers and genetics, canker sores may be associated with problems in immune function, emotional stress, nutritional deficiencies, hormonal changes, and food allergies. Bottom line, there does not appear to be one particular cause of these mouth ulcers, but their development seems to be triggered by a number of interacting factors.

Symptoms of Canker Sores

Before appearing, the area in which a canker sore develops may experience a tingling or burning sensation. Once the ulcer develops, it typically takes one to three weeks to heal, although large mouth ulcers may take longer to resolve. More severe canker sore outbreaks may be accompanied by symptoms of illness, including fever, lethargy and swollen lymph nodes.

If canker sores are bothersome or persistent, a physician should be consulted to rule out more serious disease, such as herpes, drug allergies, erythema multiforme, bullous lichen planus, squamous cell carcinoma and other types of mouth ulcers.

Avoiding a Canker Sore Outbreak

Canker sores do not appear to be precipitated by a single cause, have no cure, and often reoccur. Still the frequency of outbreaks may be reduced by:* avoiding acidic and spicy foods that irritate the mouth
* avoiding gum chewing, which can irritate the mouth
* using a soft-bristled tooth brush and brushing and flossing regularly to maintain good oral health

Treatment of Canker Sores

It is not usually necessary to treat canker sores, as they typically resolve on their own. However, when a canker sore is present, the person afflicted should avoid spicy or acidic foods, which can cause discomfort. Non-prescription mouthwashes, rinsing with salt water or dabbing the affected area with diluted hydrogen peroxide may help relieve symptoms.

There are also over-the-counter topical medications that can be applied to the affected area for soothing pain. For severe outbreaks, topical or systemic steroids may be prescribed to reduce the length and severity of the eruption.

Sources

Femiano F, Lanza A, Buonaiuto C, et al. (2007) "Guidelines for diagnosis and management of aphthous stomatitis." Pediatr Infect Dis J, Issue 26:728-732.

Gonsalves WC, Chi AC, Neville BW. (2007) "Common oral lesions: Part I. Superficial mucosal lesions." Am Fam Physician. Volume 75(4):501-507.

National Institutes of Health, MedlinePlus (2009). "Canker sores."

WebMD (2009). "Dental Health and Canker Sores."