Consult Your Pharmacist - Advising Patients About Oral Ulcers

Steven Pray, Ph.D., R.Ph., Professor of Nonprescription Products and Devices, School of Pharmacy, Southwestern Oklahoma State University, Weatherford, OK

US Pharmacist. 2000;25(1) 

In This Article

Minor Recurrent Aphthous Ulcers

Minor recurrent aphthae comprise 70%-90% of aphthous ulcers and are also known as canker sores.[5] This month's patient information page describes the common lesion and provides information to help patients differentiate it from more serious oral lesions, such as oral cancer.

Many typical methods of diagnosis (e.g., biopsy, microbial culture) are not appropriate for canker sores. In fact, no laboratory examination is capable of confirming their presence.[4] For this reason, they are recognized through visual inspection in most cases. In order to recognize them, the pharmacist must keep the descriptions of other aphthae in mind.

Canker sores have several common characteristics. They are either round or oval, are shallow, have regular borders, are about 5 mm in diameter, are surrounded by a red erythematous halo, and have a pseudomembranous interior of gray-white or yellowish fibrinous exudate.[3] The sores are painful, usually so much so that they inhibit activities that involve oral movements.

Canker sores (and other forms of aphthae) are located on areas of intraoral surfaces that do not overlie bone. These nonkeratinized areas include the mucosa of the labial surfaces and inner cheeks, the sulcular areas of both jaws, the portion of gums not attached to underlying bone, the soft floor of the mouth, the tongue, the soft palate, and the tonsillar areas.[3,5] In many cases, the patient is able to either pull out the cheek or lip or stick out the tongue to show the lesion to the pharmacist. If the patient cannot do so, the pharmacist cannot visually confirm whether it is located on soft or hard palate or the bone-backed portion of the floor of the mouth.

It is better in these cases to refer. This is especially wise when the patient uses smokeless tobacco products because oral carcinoma may be present.

Many patients undergo a prodrome, usually a painful or tingling area of the intraoral mucosa.[4] Next, the area develops into a red papule and is quickly surrounded by its erythematous halo. Within a short period, the papule ulcerates, with the interior developing its pseudomembrane. Pain is present from prodrome through the last phases of healing. Healing to complete resolution may take as little as one to two weeks, and there is usually no scarring when healing is complete.

When pharmacists consult with patients about canker sores, the question often arises, "Why do I get these things?" According to folk wisdom, the canker sore is related to stomach ulcers in both appearance and etiology, so their appearance either means that one has gastric ulcers or will eventually develop them. The pharmacist can tell patients that the relationship is spurious and the two are unrelated in the vast majority of cases. If they do coexist, there is rarely a single etiologic factor responsible for both.

Research has pointed toward a possible genetic predisposition for canker sores. For instance, the highest incidence of canker sores in one study was seen in children whose parents both had canker sores.[4] As many as 50% of first-degree relatives of those with canker sores share the disorder.[5] However, this correlation may well reflect other common factors such as similar personalities, domestic histories (exposure to certain factors in the home while growing up) or psychological environments.[3]

Many patients with canker sores can remember some trauma to the oral mucosa that preceded the lesion, such as accidental bites, dental injections, or a sports injury (e.g., an elbow hitting the mouth).[3] Trauma is said to be the most common precipitating factor, perhaps because it provides an entry point for bacterial pathogens.[4] The fact that trauma is less common over keratinized areas may explain the occurrence of canker sores in nonkeratinized tissue locations.[3]

Organisms may play a role in canker sores, with L-forms of streptococci often being isolated from them.[4] Researchers also isolated Helicobacter pylori from canker sores.[6] Medications may induce oral ulcerations that mimic canker sores. One report implicates nicorandil, a potassium-channel activator available in England.[7]

Anecdotal reports have long implicated sodium lauryl sulfate (SLS), a detergent ingredient found in most toothpastes.[8,9] Experimental work has been equivocal, but patients continue to report resolution of canker sores when they begin use of SLS-free dentifrices. Various diet-related etiologies have been proposed, ranging from vitamin deficiencies (e.g., B12, B1) to food allergies.[2,5,10] Although each may cause a certain percentage of canker sores or canker-like lesions, none can be considered a major cause.

For patients who are prone to canker sores, pharmacists can recommend gingival protectants, also known as covering agents.[1,11,12] The products protect the oral mucosa from trauma that might induce a canker sore. Benzoin compound and benzoin tincture are approved for this use. Products such as Orabase Plain do not contain benzoin, but may be effective. Some patients use orthodontic waxes (e.g., Butler Orthodontic Wax) to cover sharp appliances, such as braces, which might abrade the mucosa.

Cleansing is one way to treat canker sores.1 Because the sores are mucosal craters, food particles may collect in them, and pain will inhibit cleansing. The FDA approved four ingredients for this purpose: sodium perborate monohydrate, carbamide peroxide, hydrogen peroxide and sodium bicarbonate. Sodium perborate monohydrate (in products such as Amosan) contains potentially toxic boron; therefore, pharmacists must advise patients not to swallow the product and not to allow use in children under age 6. Sodium bicarbonate is appropriate for patients age 2 and older and is used by dissolving one-half to one teaspoon of the product in 4 oz. of water and swishing around the mouth. Patients may simply follow package directions when using products containing hydrogen peroxide (Peroxyl Antiseptic Dental Rinse) or carbamide peroxide (Cank-Aid, Gly-Oxide, Orajel Perioseptic, Proxigel).

Patients may treat the pain of canker sores with judicious use of products containing local anesthetics such as benzocaine (Orabase-B, Anbesol, Benzodent, Orajel Mouth-Aid, Rembrandt Canker Pain Relief Kit, Tanac), phenol, benzyl alcohol, dyclonine, hexylresorcinol, or menthol.[1] However, patients must not use the products longer than one week, and the products should not be recommended for children under the age of 2 (unless used for teething).

If a patient experiences rash or fever with oral ulcers, or if irritation, pain or redness persist, he or she should see a doctor or dentist.

Remember, if you have questions, Consult Your Pharmacist.

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