Fortunately most mild cases of canker sores will go away on their own; yet, some aphthous ulcers are so painful or extensive that medical treatment is necessary. Since the precise cause of canker sores is unknown, the illness is somewhat difficult to treat. The main goal of canker sore treatment is to shorten the amount of time the sore is in the mouth and to reduce the amount of pain that it causes.

Corticosteroid treatment for canker sores

Corticosteroids are the primary medical treatment for canker sores. These agents reduce inflammation and irritation in and around the aphthous ulcer. For mild and moderate cases, the steroids are administered topically, that is, the canker sore treatment is placed directly on the lesion itself. For more severe cases, a systemic (oral or injected medication) corticosteroid might be needed.

The type, strength and concentration of topical corticosteroids vary greatly; some steroids are dilute enough to be sold over the counter while others require a prescription. These topical agents may be sold as creams, ointments, pellets, pastes, sprays or mouth rinses. The way in which these medications are administered does not seem to affect the medication’s efficacy. Therefore each patient is free to decide which topical canker sore treatment to use (rinse versus paste, for example) with the guidance of a physician.

Hydrocortisone and triamcinolone

Hydrocortisone is perhaps the most well known corticosteroid and is often the first line treatment for aphthous ulcers. Low concentration topical treatments, up to 1%, are available over-the-counter. Higher concentrations of hydrocortisone are available by prescription and may be more effective. Triamcinolone is almost as equally well-known as hydrocortisone and is also available with or without a prescription. Hydrocortisone and triamcinolone are placed directly on the canker sore two to three times a day.

Hydrocortisone and triamcinolone can heal canker sores by reducing the number of inflammatory white blood cells that are attracted to the canker sore. Fewer cells around the lesion mean less inflammation and tenderness. While these drugs can heal canker sores during a given flare-up, they do not prevent the aphthous ulcers from recurring.

Fluocinonide and fluocinolone

Fluocinonide and fluocinolone are more potent topical corticosteroids than hydrocortisone or triamcinolone. As such, these drugs are available by prescription only. Fluocinonide is generally dispensed as a 0.05% cream or ointment while fluocinolone is distributed as a 0.025% ointment. Not only do these drugs prevent new white blood cells from being attracted to the canker sore, they also prevent white blood cells that are already in the area from dividing and forming new inflammatory cells. While fluocinonide and fluocinolone are quite potent, they are also associated with a greater risk of fungal infections in the mouth, such as oral thrush.

Clobetasol

Clobetasol is the most potent, commonly available topical corticosteroid. It does the work of the all of the above mentioned drugs (decreases migration of inflammatory cells and prevents them from multiplying) but also stimulates the secretion of proteins that suppress inflammation. Clobetasol is dispensed as a 0.05% gel by prescription only. There is an increased risk of viral and fungal infections of the mouth when using clobetasol. Also, since it is so potent, the corticosteroid may suppress the function of the adrenal glands. This may affect the release of the body’s natural steroids as well as create problems with sodium, potassium, and water balance. Therefore, clobetasol is used with particular caution in the treatment of aphthous ulcers.

Prednisone and dexamethasone

These corticosteroids are generally reserved for the worst cases of aphthous ulcers. Prednisone is a commonly used, but powerful, oral anti-inflammatory drug. The medication is used with a considerable amount of caution since it suppresses the entire immune system. Dexamethasone is most often used as a potent, intravenous corticosteroid. As a medicine for canker sores, the drug is used as a “swish and spit” or “swish and swallow” medication. If either of these medications is used for more than about five days, the dose should be reduced gradually (tapered) to avoid creating a steroid withdrawal syndrome.

References

Eisen D, Lynch DP. Selecting topical and systemic agents for recurrent aphthous stomatitis. Cutis 2001;68:201-206.

Quijano D, Rodriguez M. [Topical corticosteroids in recurrent aphthous stomatitis. Systematic review]. Acta Otorrinolaringol Esp 2008;59:298-307.