Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Canker sores are diagnosed by taking a careful history and observing the ulcers' typical appearance. No testing is needed in the majority of cases. However, if the diagnosis is uncertain, the disease is more severe, or other symptoms are present, the doctor may perform certain blood tests and even do a biopsy of the ulcer.
The doctor, however, must consider the possibility of herpes or fungal infections, trauma, or sores that will not heal that could signal cancer.
Canker sores may be seen in people with HIV infection, with inflammatory and other bowel diseases, and with certain medical conditions.
Herpetiform aphthous ulcers may be distinguished from true herpes sores by the fact that with the herpetiform canker sores, no vesicles (small blisters) appear before the ulcers do.
Try rinsing your mouth with a solution of ½ teaspoon salt dissolved in 8 ounces of water.
Another mixture that may be helpful consists of 1-2 tablespoons of Maalox mixed with ½ tablespoon of liquid diphenhydramine (Benadryl). Swish a teaspoonful in your mouth and spit it out. This can be done four times a day. Make sure that you do not swallow the mixture, and be careful when using this remedy with children since the Benadryl can cause toxicity.
Some authors recommend the use of calamine (Calamox) lotion applied topically to the ulcer. However, this is an unapproved use and there are no controlled studies to support its safety or efficacy.
Liquids or ointments with a numbing ingredient such as benzocaine (Anbesol, Oragel, Orabase, Zilactin-B, Tanac) help relieve the discomfort of canker sores. It is important to be careful not to use more than the recommended amounts per day to avoid toxicity.
However, in April 2011 the U.S. FDA issued a warning about an association between benzocaine and methemoglobinemia, a rare but serious condition in which oxygen delivery to tissues is compromised. Because of this association, the FDA has stated that benzocaine products should not be used on children less than two years of age, except under the advice and supervision of a health care professional. Further, adults who use benzocaine gels or liquids to relieve pain in the mouth should follow the recommendations in the product label. Benzocaine products should be stored out of reach of children, and FDA encourages consumers to talk to their health care professional about using benzocaine.
There are a number of over-the-counter medications that can be purchased to help alleviate the pain from the ulcer. Most of these have limited studies to support their use and may not be of any benefit:
Glycyrrhiza extract (CankerMelts) which comes from the root of licorice plant. This has been shown in one study to improve healing and decrease pain of canker sores.
Vitamin B-12 (Avamin Melts): Although recommended by some authors, it has no well performed studies to support its use.
A gel containing polyvinylpyrrolidone, sodium hyaluronate, and Aloe Vera (Canker-X): There is limited evidence supporting the benefit of this compound.
Alternative or naturopathic remedies have limited study but are recommended by some providers. Do not use any of these therapies without first consulting with your medical provider. There is almost no evaluation of drug interactions and possible side effects with these naturally occurring compounds. These include the following:
Rhodiola Rosea - 200 mg capsule once a day
Glycyrrhiza glabra - given as a tea or as a tablet
Coptis supp, Hydrastis canadensis root -- diluted in water and applied to ulcers as needed
Mahonia aquifolium root - tincture or tea applied topically to ulcers as needed
Spilanthes acmella flower - tincture or tea applied topically to ulcers as needed
Alchemilla vulgaris leaf - tincture or tea applied topically to ulcers as needed
Myrtus communis leaf - Mix power in water and apply to ulcer as needed