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What Causes Canker Sores?

By - Bad Breath Expert

If you have small, shallow lesions that have developed at the base of your gums, inside of your mouth or on the inside of your cheeks, chances are you have developed canker sores. Individuals can have one or multiple canker sores and they can occur not only at the base of your gums but also on the walls of your mouth, the inside of your lips or underneath your tongue. Canker sores are also referred to as aphthous ulcers because they have the appearance of a small round white or yellowish center with a red border. Just before canker sores appear, individuals note a burning or tingling sensation a day or so before the actual sore(s) develop. Please note, that these sores or lesions are not contagious, unlike cold sores, but can be quite painful and in some cases can make talking and eating somewhat difficult. Most people who suffer from canker sores find that these sores do not last for an extended period of time; generally, they last for only a week or two and then they heal on their own. While the sore is present, again, it is not a very pleasant experience. So individuals may be interested in learning what causes canker sores and what, if any, treatments are available.

Canker Sore Symptoms

what causes canker sores?Canker sores come in several different classifications such as minor, major, and herpetiform sores. Minor canker sores are the most common and are very small in size (less than half an inch in diameter). These sores generally will heal within one to two weeks. Minor canker sores cause no scarring. Next, are major canker sores, and these sores are typically larger than a half an inch in diameter and take a much longer time to heal than minor canker sores. The average healing time for these sores is about six weeks and there is quite a bit of scarring that occurs as a result of major canker sores. Unlike minor canker sores, this classification of canker sores is a lot less common. Lastly, there is what is called herpetiform canker sores and are much smaller than minor canker sores (approximately 1/8 of an inch) but these tiny sores occur in clusters instead of a singular sore. An individual can have as little as 10 sores in a grouping or as many as 100. Much like minor canker sores, herpetiform canker sores heal without scarring within one to two weeks. It is important to note that unlike cold sores, and as the name would suggest, herpetiform canker sores or any classification of canker sore is not associated in any way with the herpes simplex virus.


In terms of the symptoms, the lesions and the pain are the primary symptoms. However, some individuals may experience other symptoms accompanying the canker sore and these symptoms can include but may not be limited to: fever, fatigue or listlessness, and swollen lymph nodes. These symptoms should not be cause for alarm, however, if you are experiencing sores that are unusually large, and the sores last for more than three weeks, the pain cannot be remedied with any self-care treatments, you have recurring sores meaning that new sores develop before the old sores have had a chance to heal, or you have an unusually high fever that accompanies your canker sore then you should seek medical attention immediately.

Canker Sore Causes

Doctors and researchers have not reached a clear consensus on what causes these canker sores. However, doctors have concluded that several factors can contribute to outbreaks in individuals be it a singular episode or one that occurs every so often with individuals. These factors include but are not limited to:


  • Injury to your mouth that resulted from a sports injury, an accidental cheek bite, dental work, or even over-active teeth brushing.
  • If you have any food sensitivities or are allergic to certain foods, to certain foods like coffee, eggs, highly acidic foods, or chocolate, eating them can encourage the development of canker sores.
  • Improper diet and experiencing a deficiency in certain vitamins such as iron, folic acid, zinc, or vitamin B-12.
  • Certain diseases that cause your immune system to shut down or not properly function such as HIV/AIDS.
  • Celiac disease, which is an intestinal disorder that is characterized by sensitivity to gluten.
  • Behcets disease is a very rare disorder that causes certain inflammations in the mouth and all throughout the body.
  • Certain toothpastes even mouth rinses that contain the cleaning agent sodium lauryl sulfate.
  • Stress

No conclusive evidence points to canker sores being a hereditary condition, although, according to research about one-third of individuals that have recurring sores do have a shared family history of canker sores with other family members. There may be a genetic factor but it also can be attributed to other shared factors such as allergens, or other disorders.

Evidence does show that although anyone is susceptible to canker sores, more often than not women are more likely to develop canker sores than men, especially the herpetiform classification of canker sores.

Canker Sore Treatment

Generally, aside from the pain, treatment is not really needed when it comes to the more common, minor canker sores. Additionally, since they clear up on their own, during the time you are subjected to those canker sores, they are more of a nuisance than anything. Again, if you are experiencing larger sores that are accompanied with excruciating pain and high fevers, then should see a doctor for further analysis. There are several treatment options available to individuals who are suffering through painful and unusually large canker sores and treatment can range from topical ointments to mouth rinses and even systemic corticosteroids for the more severe cases.


There is no test or diagnostic exam other than a visual test that your doctor will perform and from there, he will be able to determine what treatment options would be best. If you have a cluster of canker sores that are painful and making it very difficult to eat or talk, your doctor may prescribe a mouth rinse that contains an active ingredient called steroid dexamethasone in order to reduce any excess swelling, inflammation, and pain. Your doctor may also prescribe a topical paste or even recommend an over-the-counter ointment that will help relieve any pain you may be experiencing as well as speed healing time.

Again, because a factor that may contribute to your developing canker sores is a deficiency in important vitamins and minerals, your doctor may prescribe or suggest a nutritional supplement that will help boost those low levels in your body. In doing this, it can help prevent the recurrence of canker sores in the future.

Needless to say, if your canker sore is a symptom of a more serious medical condition, your doctor will need to perform additional tests in order to determine what that underlying condition is, so that it may be treated.

If your canker sore is much more of a nuisance than a medical emergency, there are things that you can do at home in order to relieve any discomfort associated with the sores. For example, try a mouth rinse consisting of either salt water, one part baking soda (about a teaspoon) and a half cup of warm water, or hydrogen peroxide diluted in water. In order to numb the pain, try an over the counter numbing product. You can also apply ice to the sores in order to help with pain. Additionally, in order to not exacerbate the sore, try brushing your teeth gently and with a toothpaste that does not have any foaming agents like sodium lauryl sulfate, such as TheraBreath.

Alternatively, try to de-stress whenever possible as this can help lessen some of the pain associated with a canker sore such as yoga or meditation.

TheraBreath® Products to Treat Canker Sores

Sufferers of chronic canker sores will find quick relief once they begin using any of the specially formulated TheraBreath toothpastes created by Dr. Harold Katz. Dr. Katz, the renowned dentist and bacteriologist responsible for providing consumers with the most effective oral hygiene products currently available, has conducted extensive research into oral hygiene issues such as bad breath, canker sores, tonsil stones and periodontitis. As a result, he discovered that these problems arise from chronic dry mouth syndrome, the proliferation of anaerobic bacteria and an environment devoid of oxygen. This knowledge allowed him to develop the line of TheraBreath oral hygiene products.


In addition, he also found that many name brand toothpastes contain an abrasive, foaming agent called sodium lauryl sulfate, a surfactant that is also included in cleaning products like detergents and shampoos. Researchers have correlated SLS with recurring canker sores due to its caustic nature and capacity to irritate sensitive mouth tissues to the point of sloughing them off the insides of the mouth. This extra protein-rich mouth debris caused by using toothpaste with SLS further exacerbates halitosis and the development of tonsil stones. Because all TheraBreath toothpastes do not contain SLS, users will not suffer from abraded tissue loss and the pain of recurring canker sores while also reducing bad breath and tonsillolith formation.

Canker Sore Prevention

Unfortunately, some people will develop canker sores at some period in their lifetime but you can lessen the likelihood of a re-occurrence by implementing a few tips that will prevent these sores from coming back. As the old saying goes, an ounce of prevention is worth a pound of cure.


Take care in what you eat. Stay away from foods that you are allergic to or have a sensitivity to. Whenever possible, always choose healthier foods over unhealthy foods. You will get a lot of vitamins and nutrients that the body needs in order to ward off bad bacteria. Make sure you implement good hygiene habits such as brushing, flossing, and using a mouth rinse. It is important to use a soft bristle brush as this can lessen an inflammation that can result from overzealous brushing. Lastly, try to protect your mouth as much as possible. Try to avoid using toothpastes or rinses that contain sodium lauryl sulfate because this particular cleaning agent has been found can encourage the proliferation of canker sores with some individuals. Wear mouth guards when engaging in sports activities and if you have dental appliances such as braces, use things like orthodontic waxes to cover any sharp edges.

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