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Home > Dental Conditions > Cold Sores > Cold Sore Symptoms & Causes > Canker Sore 101 A Complete Guide to Canker Sores
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Canker Sore 101: A Complete Guide to Canker Sores

Canker Sore - Canker Sores are a common cause of mouth pain symptoms.

Small in size, big in impact, a canker sore can reduce the toughest among us to tears. Dentists refer to canker sores as aphthous ulcers or recurrent aphthous stomatis. Regular people have more colorful names for them ... usually something along the lines of @#$%^&*! Until you experience one, it's hard to believe that something so tiny (many canker sores are 1-2 millimeters) could hurt so much.

At first, a canker sore seems like no big deal. You might notice it as an almost imperceptible burning or tingling sensation on the inside of your mouth. You'll think, "Am I really feeling this?" You are. Soon, you'll start wondering if this increasingly painful feeling is going to disrupt your daily life. It will. Expect eating and speaking to become a problem. Then, you'll start praying that it goes away quickly. It won't. Five days of searing mouth pain and 10 to 14 days of symptoms are typical.

What Is a Canker Sore?

A canker sore is a common dental condition that appears as a small white, gray or yellow ulcer surrounded by a red halo. Invisible to others, canker sores occur on the soft tissue inside the mouth, often on the inner surface of the lips, throat or cheeks. A canker sore on the tongue, soft palate or at the base of the gums is not unusual.

There are three classes of canker sores. Minor canker sores are the most common and mildest form. These oval-shaped ulcers -- less than 12 millimeters in diameter -- heal without scarring in one to two weeks. Major canker sores are larger in size, have irregular shapes and take up to six weeks to heal. This form leaves extensive scarring. The third type, herpetiform canker sores, appear later in life. While an individual herpetiform canker sore is only about three millimeters in diameter, these irregularly shaped ulcers have the nasty habit of occurring in clusters of 10 to 100. Fortunately, they heal without scarring in one to two weeks.

What Causes Canker Sores?

No one is sure what causes canker sores to erupt. What is known is that women are more likely than men to get a canker sore, symptoms of canker sores rarely occur before the age of 10, and, according to the Mayo Clinic, about one-third of people with recurrent canker sores have a family history of the disorder. Individuals suffering from a canker sore outbreak occasionally experience other symptoms, including fever, listlessness and swollen lymph nodes.

While the exact causes of canker sores are unknown, outbreaks appear to be related to the following factors:

  • Heredity
  • Smoking
  • Emotional stress
  • Food sensitivities & allergies
  • Mild tissue injuries to the mouth
  • Hormonal changes related to menstruation
  • Dietary deficiencies (specifically iron, zinc, folate and vitamin B12)
  • Celiac disease (an intestinal disorder caused by a sensitivity to gluten)
  • Inflammatory bowel disease (Crohn's disease and ulcerative colitis)
  • Behcet's disease (a form of vasculitis that can lead to ulceration)
  • HIV, AIDS and other conditions affecting the immune system
  • Toothpastes & mouth rinses containing sodium lauryl sulfate

Are Canker Sores Contagious?

Are canker sores contagious? That's the one thing friends and family want to know as soon as a canker sore makes its first painful appearance. The good news is that unlike cold sores canker sores are not caused by a contagious virus. Unfortunately, that's about it for good news regarding the lowly canker sore. Other than not being infectious, canker sores rank high among life's more miserable mouth problems. A canker sore on the tongue is particularly painful.

Treating Canker Sores

Is it worthwhile visiting the dentist every time you get a canker sore? The answer is generally "no."  Canker sores usually get better by themselves over time. However, in some instances, people who thought they were dealing with a canker sore were actually experiencing oral cancer symptoms. As a rule of thumb, see your dentist if a canker sore doesn't heal on its own after two weeks. Unusually large canker sores, recurring ulcers, and sores accompanied by a high fever, diarrhea, headache, or skin rash should always be checked out by your dentist.

Dentists treat canker sores in a variety of ways with a primary focus on providing pain relief. First, your dentist will determine if your canker sore is related to a more serious health problem. If so, treatment will focus on the underlying cause. Otherwise, your dentist will likely treat your canker sore using one of the following approaches:

Mouth Rinses - Mouth rinses containing the steroid dexamethasone are often prescribed to reduce the pain and inflammation related to canker sores. Some dentists may recommend oral suspensions of the antibiotic tetracycline to relieve pain and cut healing time. The downside to tetracycline is that it makes you more susceptible to the fungal infection oral thrush and it can permanently discolor children's teeth.

Debacterol - This topical solution speeds healing by chemically cauterizing the canker sore.

Oral Medications - Canker sores are often successfully treated with medications not specifically designed for that purpose. The heartburn drug cimetidine and the gout medication colchicine are particularly effective at reducing symptoms. Oral steroids may be prescribed as a last resort when severe canker sores don't respond to other treatments.

Topical Pastes - Recovery time can be shortened and pain lessened by applying over-the-counter (OTC) or prescription pastes containing benzocaine, amlexanox and fluocinonide directly to a canker sore.

Nutritional Supplements - Your dentist may recommend boosting your intake of nutrients like folate (folic acid), vitamin B-6, vitamin B-12 and zinc to improve your overall health and increase your resilience to canker sores.

OTC and Home Remedies for Canker Sores

People have been self-treating canker sores for hundreds, if not thousands of years. The Mayo Clinic reports that some of the most effective methods that have emerged include:

Homemade Mouth Rinses - Rinsing your mouth with salt water, baking soda (dissolve one teaspoon of soda in one half cup of warm water), or hydrogen peroxide diluted in half by water can reduce canker sore symptoms. Make sure you spit out the mixture after rinsing.

OTC Products - Numbing products like Anbesol® and Orajel® can make living with canker sore pain bearable. In a pinch, a paste made of baking soda and water applied directly to the sore will provide some relief.

Ice Chips - Applying ice chips to your canker sores can reduce the pain.

Phillips'® Milk of Magnesia - Dabbing a small amount of Milk of Magnesia on your canker sores several times a day may ease the pain and speed up the healing process.

Some people have successfully used alternative medicine to treat canker sores. The Mayo Clinic reports that popular methods include applying a paste of alum, slippery elm powder or eglycyrrhizinated licorice (DGL) directly to the canker sore. Stress reductions techniques (e.g., yoga and meditation) and nutritional supplements, (e.g., zinc, folate and vitamin B) show promise for reducing your susceptibility to canker sores.

Preventing Canker Sores

While there's no proven way to prevent canker sores, you can reduce the frequency of outbreaks by following a few simple guidelines:

Eat a healthy diet. In addition to the fruits, vegetables and whole grains that promote overall health and prevent nutritional deficiencies, WebMD reports that eating yogurts containing acidophilus bacteria may reduce the likelihood of canker sores.  

Avoid foods that irritate your mouth. Be especially careful with nuts, chips, spicy foods and acidic fruits like pineapple and grapefruit.

Practice good oral hygiene. Brush your teeth and floss every day to keep your mouth free of the foods that may trigger an outbreak.

Don't chew and talk at the same time. Silly as it sounds, this kind of multitasking often results in the kind of minor mouth trauma that leads to a canker sore.

Protect your mouth. Ask your dentist or orthodontist for help if orthodontic braces, dentures or dental restorations are irritating your mouth or gums and causing canker sores.

Worried About a Canker Sore?

Medically speaking, a canker sore is more often a minor, short-term inconvenience than a major dental problem. However, if you're miserable because your pain can't be controlled through self-care measures or because you're experiencing difficulty eating and drinking, it's time to visit the dentist.

To find a local dentist who can evaluate a persistent canker sore, search now or call 1-866-970-0441.

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