Are Canker Sores Contagious?

Canker Sores
Canker Sores

Canker sores, unlike cold sores, are not contagious. Canker sores are found inside the mouth. They pose no physical threat and cannot be transmitted to another individual.


Canker sores can be categorized in three types: simple, complex, and herpetiform. Simple canker sores typically appear in people that are between the ages of 10-20 years old. Oval shaped, the blisters are around ½ inch in size. Lasting up to a week, they can appear three to four times a year.

Complex canker sores, less common than the simple, recur throughout an individual’s life. Over ½ inch in size, they have irregular edges. Lasting up to 6 weeks, they may leave some scarring.
Herpetiform canker sores most commonly occur in older individuals. They can appear in clusters of 10-100 sores, are approximately 1/8 inch in size, irregular shaped, and can disappear in a couple of weeks.


No one really knows the exact cause of canker sores. Some dentists and doctors believe that canker sores can be triggered by stress or an oral injury like biting the inside of your cheeks. It may also be from acidic or citrus foods and fruits. Poorly fitting dentures or injuries from braces or a sharp tooth may also cause canker sores. They can also run in families.

Complex canker sores are believed to be related to underlying health problems. Nutritional deficiencies in vitamin B-12, iron, folic acid, or zinc may also contribute to their occurrence. Gastrointestinal tract diseases like celiac or Crohn’s may trigger the appearance of the complex canker sores.

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The top reasons why people get canker sores

Nutritional Deficiency

Several studies have indicated that canker sores can be triggered if there is a deficiency of zinc, folic acid, or iron in your body. Also, if you have a calcium deficiency, canker sores can show up, but a calcium deficiency does worse than just cause them – it can worsen your situation. If you are dealing with a nutritional deficiency, the best solution for you would be to turn to healthy eating.

Vitamin Deficiency

Many times a vitamin deficiency can cause canker sores to form. More specifically, if you are lacking the vitamin B-12, canker sores may show up. It’s a known fact that kids need more vitamins than adults, because kids are growing, which calls for more vitamins. Plus, you also have to consider the fact that a large amount of vitamins are found in fruits and vegetables, which are something many kids are not too fond of.

Having a Poor Immune System

Canker sores can be blamed on having a poor immune system. We cannot find the direct relation between having a poor immune system and canker sores, but it could be because when an individual has a poor immune system and they get canker sores, the body is not able to properly repair itself quickly. Plus, there is evidence that various diseases and gastrointestinal problems can cause canker sores to form.


Canker sores come in the form of painful lesions that can be found on the tongue, on the inner cheeks, and on the soft palate of the mouth. Burning or tingling sensation is often a precursor to their appearance. The sores are round with red edges and may appear white or gray in color. In more severe cases, they may be follow with sluggishness, a mild fever, and some swelling of the lymph nodes on the neck.

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For the majority of the cases, no treatment is necessary. The pain and discomfort eases in a few days. The sores themselves will disappear on their own in about a week. If the sores become large, more painful, or recur often, your dentist may prescribe an ointment, an antimicrobial mouthwash, and/or a pain-relieving solution.

Home remedies that can help relieve canker sores


Do you have an aloe plant in your home? If not, you can go to the store and buy some aloe vera gel. By applying this to the sores, it can speed healing and offer pain relief. Before you apply the gel, dry the sore area with a cotton swab and dab a small amount of the gel right on the sore. You can repeat this step as often as you need.

Baking Soda

Believe it or not, baking soda can be a nice home remedy because it is an alkaline that will neutralize the acids that are causing irritation to the canker sore. Take a half cup of warm water and mix 1 teaspoon of baking soda in it – rinse your mouth with this solution.

A Tea Bag

Tea is an alkaline, like baking soda, so it will do the same and neutralize acids that are irritating the sore. Tea is a good one to try, because it has compounds in it that could help relieve the pain you have been feeling. Take a damp tea bag and place it on the sore – leave it there for a total of five minutes. After five minutes, you should start to feel some relief. You can repeat this as often as you like.

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As you see, there are many at home remedies you can try that will speed up the healing and relieve the pain you are experiencing. The three we just recommended are at the top of our list of at home remedies for canker sores.


As you may already know, the cause of these sores remain unknown, so this means canker sores have no cure. This also means that nothing can prevent them. Preventive measures can be taken to reduce the frequency of recurrences. Avoiding excessive amounts of citrus fruits, acidic vegetables, and spicy foods can help prevent their appearance. Changing to a softer bristled toothbrush and flossing daily can also help prevent gum irritation.