Canker SoreA canker sore, also known as an apthous ulcer, is an open sore or ulcer in the mouth. It is painful, especially on talking or eating. They are generally small lesion that develop on the soft tissues of the mouth or the base of the tongue. Canker sores are yellow or white and surrounded by a ring of bright red tissue.

Canker sores are not related to cancer. Neither are they related to an sore outside the mouth such as cold sores on the lips. They are not contagious and there is no evidence of viral involvement.


Canker sores are the most common type of mouth ulcer. They may occur at the same time as viral infections but are not related to viral caused sores. Quite often a cause can not be determined.

We do know that canker sores are often linked to problems with the body’s immune system. The most common identifiable cause is tissue trauma which happens just before the canker sores appears. Women have more canker sores than men. We also see that Canker sores can run in families. That said, canker sores can and does affect almost anyone from time to time

Canker sores can also be triggered by the following:

  • Lack of certain vitamins in the diet especially vitamin B-12 or folic acid.
  • Hormonal changes including menopause and the menstrual cycle.
  • Stress, both physical and mental.
  • Food allergies or allergies to mouthwash or toothpaste ingredients.

Canker Sores Symptoms

Canker sores usually appear on the inner surface of the cheeks and lips. They are occasionally found on the tongue, the gums. and soft palate.

Symptoms include:

  • One or more painful, red spots, bump or ulcers that develop a very sensitive open concave area.
  • The center of the sore is yellow or white
  • Usually under 1 cm but occasionally much larger
  • Sore may turn a grayish color just before beginning to heal

The Pain usually goes away in 5 to 10 days. It can take 1 to 3 weeks for a canker sore to completely heal. Large ulcers can take up to a month to heal. It is not unusual that during a severe outbreak of canker sores to have nonspecific symptoms such as fever, swollen lymph nodes, or fatigue.

Exams and Tests

A health care provider such as Dr. Navid Safaei,, a well trained Encino Family dentist, can often make the diagnosis by looking at the sore.

If canker sores return or persist, or are very frequent tests should be done by a physician to look for diseases such as lichen planus, erythema multi forme, drug allergies, or a herpes infection.

Canker sores are not cancer and do not cause cancer. There are types of cancer, however, that may first appear in the mouth as a ulcer that does not heal. At times a biopsy may be used to distinguish a canker sore from other causes of mouth ulcers. A family dentist may be trained in taking biopsies. I take many in my Encino dental office.

New Treatments:

In most cases, the canker sores go away by themselves. Severe cases may be so uncomfortable that treatment is necessary for pain relief.

A diode laser is the newest and most advanced treatment. It can done in my office . Our office was one of the first Encino family dentists to offer this service. A few moments exposure to the laser causes rapid pain relief and healing.

Traditional Treatment:

Weak salt water or mild mouth washes may help. There are over-the-counter medicines that soothe the painful area by covering them. These medicines are applied directly to the sore area of the mouth.

Another home remedy is to mix half Milk of Magnesia and half Benadryl liquid. Swish this mixture in your mouth for about 1 minute, then spit it out.

Another old home remedy is a mixture of half mouth wash strength peroxide and half water. Use a cotton swab to apply the mixture directly to the canker sore.

Then place a dab of Milk of Magnesia on the canker sore four times a day. This is soothing and seems to speed help it heal.

Prescription medications may also be required in some cases. This may include Lidex gel or chlorhexidine mouthwash. Powerful anti-inflammatory medicines called steroids are sometimes used. A common one prednisone taken by tablets or injection.


The prognosis is good. Canker sores usually heal on their own. There is no residual damage to the tissues. The pain usually decreases in a few days. Other symptoms disappear in 10 to 14 days.

Possible Complications

Antibiotic treatment for canker sores may lead to (a type of mouth infection) or other yeast infections. Rarely, bacterial infections such cellulites may occur.

When to Contact a Medical Professional

Apply home treatments and call your health care provider if symptoms of canker sores persist or worsen beyond two weeks or when canker sores recur more often than 2 or 3 times per year. As a family dentist in Encino I have seen hundreds of cancer sores over the years and I am quite familiar with them

Call your health care provider if the symptoms of the canker sore are associated with other problems such as fever, diarrhea, headache, or skin rash.

Intolerable pain that prevents eating, drinking or sleep is a common reason for seeking treatment. Also unusually large canker sores or spreading ones should not be ignored. A high fever is another sign of a very serious complication that calls for a physician visit.

Once again, canker sores are not cancer and don’t lead to cancer. But, if you have a mouth ulcer lasts more that 5 weeks, you should see your doctor to rule out unlikely possibility that the cancer is masquerading as a canker sore.