Canker Sores (Aphthous)



Canker sore located on the soft palate
Copyright 2006 Martin S. Spiller, D.M.D.

Canker Sores (aphthous ulcers) are very painful ulcers occurring only on unattached oral mucosa.  Unattached oral mucosa is the thin, pink “skin” in the mouth that is not directly attached to any underlying hard or firm tissues.  Examples of unattached tissue such include the cheeks, the soft palate, the undersurface of the tongue, floor of the mouth and the vestibule, which is the place in the mouth where the lips and cheeks curve around to become the gums.  They never occur on the top surface of the tongue, the hard palate (the roof of the mouth),  or on the attached gingiva.

Aphthous ulcers are pinkish white erosions which are surrounded by a halo of red, inflamed mucosa.  The one above is located on the soft palate and is especially painful during swallowing, but they can be located virtually any place in the oral cavity where there is unattached tissue, such as the cheeks, floor of the mouth, the underside of the tongue or the unattached gingiva.  They are never found in areas where the tissue is firmly attached to the underlying bone, or on the top surface of the tongue.  Canker sores generally occur suddenly and will last between 10 and 14 days without treatment.

ApthousCopyright 2006 Martin S. Spiller, D.M.D. courtesy of Dr. Ed Cataldo

Causes of aphthous 

No one knows what causes aphthous ulcers, but they are thought to be an immunologic reaction in which there is a focal immune dysfunction involving lymphocytes (a type of white blood cell).  In other words, they appear to be an overreaction of the immune system to some sort of localized irritant.  They often to appear during or just after times of stress, or sometimes after physical trauma to the area.  They are very common after dental visits.

Citrus fruits such as oranges and lemons, physical trauma, stress, lack of sleep, sudden weight loss, hormonal changes, food allergies and disorders that depress the immune system are thought to  contribute to aphthous formation.  Deficiencies in iron, vitamin B12, folic acid, and possibly zinc appear to be associated with chronic, or major aphthous (Sutton’s disease).  Aphthous ulcers are also associated with Bechet disease, Celiac disease (allergy to wheat) and Chrohn’s disease.  Major aphthous is especially prevalent in patients with HIV.

Foods associated with triggering aphthous sores include bovine milk protein, glutens, chocolate, nuts, cinnamon,nuts, spices and preservatives. The most commonly used medications reported to cause aphthous lesions are nonsteroidal anti-inflammatory drugs such as Ibuprophen (Advil, Motrin etc.) Naproxin sodium (Aleve, Anaprox etc) and many others.

It is not uncommon for some people to be prone to aphthous after trauma to the mouth.  Minor injuries to the oral mucosa may cause multiple or large aphthous lesions.  Examples of this type of trauma are injuries caused by accidentally striking the gums with a toothbrush, injury with a sharp food item, like a taco chip, or burns with hot foods like pizza.

Interestingly, people who smoke rarely have problems with aphthous stomatitis. This is probably due to the thickening of the mucosa, which is a pathological change induced by cigarette smoke on the lining of the mouth. People who have thicker mucosa lining their mouths tend to have fewer bouts with aphthous. This probably explains why vitamin B12 works as a treatment modality.

Types of aphthous and their treatment

This condition happens in three varieties; minor, major and herpetiform.  Each type has its own treatment protocol. To date, the treatment of recurrent aphthous ulcers is primarily palliative, and symptomatic, however every effort should be made to eliminate predisposing allergens from the patient’s diet and daily regimine. It is very helpful for the patient to keep a food diary for two weeks to identify the dietary triggers of aphthous lesions. Once identified, the recurrence rate of the ulcers will decrease in proportion to the patient’s ability to eliminate the trigger.

1. Minor aphthous

Minor aphthous is defined as the occasional, small ulcer that most persons experience no more than once or twice a year.  These lesions are generally small (2-4 mm), and the ulcers are treated as isolated entities (one at a time). Minor aphthous sores heal within two weeks and are less than or equal to .5 cm in diameter.

Treatment of minor aphthous
  • Topical applications of steroids
  • Lidex gel® (fluocinonide 0.05%)
    • Disp: 30 gram tube
    • Sig: Apply thin coat to ulcer after meals. do not eat or drink for 30 minutes after application. Do not use for more than two weels

Risk of mucosal atrophy and systemic absorption if used for prolonged period

  • Kenalog in Orabase ® (Triamcinolone 5% in oral paste)
    • Disp: 1 tube
    • Sig: apply to ulcer four times per day after eating and at bedtime.

(Note: Lidex is approximately ten times stronger than Kenalog, but Kenalog has the advantage of the Orabase which acts as a Band-Aid and keeps it in place longer).  These drugs are applied after meals and before bedtime, and both are prescription drugs.  They generally reduce or eliminate pain immediately and bring about resolution of the canker in two to three days.  I prefer Kenalog in Orabase in my own practice since it is designed to be used in the mouth and stays in place on the lesion.

  • Aphthasol paste ® (Amlexanox 5%)
    • Disp: 5 gm tube
    • Sig: Apply thin coat to ulcer after meals. do not eat or dring for 30 minutes after application.

Very safe with minimum side affects. moderately expensive. Unfortunately, this drug has been discontinued in the United States.

Cautery using either chemical or laser treatment.  Chemical cautery agents  include silver nitrate (generally on a wooden stick) or commercial agents such as Debacterol®, both of which are applied by a dentist or physician and offer immediate pain relief.  Over-the-counter agents such as Zilactin®, Ora5® and Gly-Oxide® are mild cautery agents that work more slowly. Laser treatment is quick and painless and also offers immediate pain relief.  Laser treatments are done only on small lesions in the dentist’s office.  This type of treatment is strictly palliative.  It destroys active lesions but does not prevent others from forming.  Using toothpastes that do not contain sodium lauryl sulfate may reduce the frequency of aphthous, although the role of SLS in aphthous is controversial.

Laser treatments for cancre sores have only recently become widely available because of the development of inexpensive diode lasers which can now be found in many dental offices. The treatment takes about ten or fifteen minutes and is totally painless. The pain associated with these sores is often relieved immediately, and the lesion itself heals within 4 days.

2. Major aphthous

also called Sutton’s disease and Recurrent Aphthous Stomatitis (RAS), major aphthous is defined as a chronic condition in which patients are plagued with multiple aphthous lesions occurring several times a month.  These ulcers are generally quite large, (larger than .5 cm) take six weeks to three months to heal, and they often heal leaving scar tissue behind.   Major aphthous associated with HIV can cause much larger lesions.  Major aphthous has no known cure, but chronic aphthous lesions may be treated using the following methods:

If you suddenly develop chronic major aphthous lesions, It is wise to check with your physician to see if there is an underlying cause such as an immune problem, or an underlying chronic illness such as Bechet, Chrohn’s or celiac disease. Major Aphthous has long been associated with inflammatory bowel disease.

Treatments for Major Aphthous
  • Vitamin B12 has been found to be effective in reducing the frequency and severity of the lesions in patients suffering from major aphthous.  1 mg is dissolved under the tongue every evening.  Some formulations of vitamin B12 are manufactured specifically for this route of administration.  Other vitamin and mineral supplements such as iron,folic acid and zinc have been known to reduce the number and frequency of aphthous lesions.
  • Dexamethasone elixir 0.5 mg/5 ml Used primarly to treat major aphthous.
    • disp: 100 ml
    • Sig: Rinse with one teaspoon for 3 minutes four times a day, after meals and at bedtime. DO NOT SWALLOW!

Risk of mucosal atrophy and systemic absorption if used for prolonged periods. Risk of secondary infection with Candida albicans

  • Betamethasone mouthwash (Betnesol mouthwash)
    • Betamethasone sodium phosphate tablets are water soluble and available by prescription
    • Dissolve one tablet in one or two teaspoons of water
    • Rinse for three minutes and spit out–DO NOT SWALLOW!
    • Repeat four times per day.
  • Tetracycline mouthwash used in herpetiform aphthous when steroid rinses fail–as a second line of defense
    • Dissolve a 250 mg capsule of tetracycline in two teaspoons of water and rinse for three minutes and spit out.
    • Do this four times a day
  • Fluocinonide (Lidex®) cream (or gel) in water
    • Disp: 30 gram tube
    • Sig: mix about 1/4 inch of  Fluocinonide (Lidex) cream or gel in four ounces of water. Rinse with one ounce for 3 minutes four times a day, after meals and at bedtime. DO NOT SWALLOW!

Risk of mucosal atrophy and systemic absorption if used for prolonged periods

3. Herpetiform aphthous

Herpetiform aphthous is a form of Recurrent Aphthous Stomatitis (RAS). The ulcers are very small (0.1 to 0.2 cm) and occur in clusters giving the appearance of a viral infection. They are NOT, however, associated with a virus as their name would imply. The clusters can be very large, up to 100 in any given area, and the individual lesions can merge together to form single very large ulcer. This form , unlike the others CAN affect keratinized tissues like the dorsum (top) of the tongue and the roof of the mouth. It affects females more often than males, older people rather than younger, and the lesions can be extremely painful. In addition, the ulcers occur more frequently and last longer than those in major aphthous. Their treatment is similar to that of major or minor aphthous and depends on the extent and frequency of their occurrence.

Other treatments for chronic aphthous

Laser treatment for aphthous

The lesions of major aphthous can be very large, painful and prolonged. The use of lasers to treat these sores can reduce the pain and duration of these lesions considerably. The treatment is painless and takes about ten or fifteen minutes. Studies have shown that in 75% of patients, the pain is relieved immediately during the treatment and the lesions heal within 4 days.

Other, more traditional methods of controlling the pain of aphthous:

Change your toothpaste to one that does not contain sodium lauryl sulfate (SLS).  Some studies indicate that SLS may precipitate aphthous in individuals who are predisposed to get these ulcers.  Tom’s of Maine offers two brands of toothpaste without SLS– Clean & Gentle and Botanically Bright. (Note: Fluoride in toothpaste has NOT been found to predispose people to this problem.)

Try a diet avoiding acidic beverages and spicy or sharp/crispy foods, such as chips.

Antiseptic mouth rinses such as hydrogen peroxide or the prescription mouth rinse chlorhexidine may reduce the discomfort.

Palliative mouth rinses made using liquid antacids such as Maalox, milk of magnesia, or other antacids reduce the discomfort from these lesions.  do not swallow these products.  Just rinse and spit. “Numbing” mouth rinses made using the above antacids mixed with Benadryl or Lidocaine.  Once again, do not swallow these mouth rinses.

Keep a food diary for two weeks to discover the food or medication that may be the allergen that may be causing the outbreak. Eliminating the trigger will reduce or eliminate the occurrance of the ulcers.

Canker sores are not contagious!

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