Canker Sores

Canker vs. Cold Sore

Canker vs. Cold Sore

Canker sores, known as aphthous ulcers to the scientific world, are painful sores that develop inside the mouth.  They can form on the inside surface of the cheeks, at the base of the gums, on the soft palate or on/under the tongue.  They are small and shallow and are round to oval in shape with the base usually covered by a white or gray membrane.  An intense red halo commonly surrounds each ulcer.

Canker sores should not be confused with cold sores.  Cold sores, also called fever blisters, are groups of painful fluid-filled blisters.  They are caused by the herpes simplex virus.  While canker sores are not contagious, cold sores are, extremely so.  They usually form on the lips and nose and sometimes on the gums.

The exact cause of canker sores is unknown.  Some people will develop canker sores after eating large amounts of citrus or acidic fruits and vegetables.  This includes, oranges, pineapple, lemons, tomatoes, strawberries, and figs.  Minor injury may also be a cause.  Injuries can be caused by overzealous brushing of the teeth, accidental cheek bite, a sharp tooth surface, or rubbing of braces/retainer.  Toothpastes containing sodium laurel sulfate (SLS) may also lead to canker sores in some people.  SLS is a chemical added to most toothpaste to create the foaming action which aids in the cleaning of teeth.

Other triggers could include:

  • Health conditions, such as celiac disease or Crohn’s disease.
  • Deficiencies in vitamins B12, zinc, folic acid, and iron.
  • Emotional stress.
  • Hormonal shifts during menstruation.

No special treatment is required for canker sores.  They will heal on their own in 1-2 weeks.  If treatment is desired, over-the-counter oral pain medication, such as ibuprofen (Motrin, Advil) or naproxen (Aleve) can be used for the pain.  Topical medications containing benzocaine, such as Anbesol, Kanka, Zilactin, and Orajel canker sore gel can be purchased without a prescription.  These medications can numb the pain and cover the open ulcer.  Prescription medications containing steroids such as triamcinolone in dental paste and Kenalog in Orabse can be used to hasten healing and decrease pain.  To prevent canker sores, avoid dietary triggers and eat a well-balanced diet.  Maintain good oral hygiene.  Protect the mouth by brushing and eating carefully.  Address problems with braces, retainers, and sharp tooth surfaces.  Reduce stress.  Avoid toothpaste with SLS, if it appears to be triggering mouth sores.

Maribeth Mulholland, MD