Canker Sores and Cold Sores Are Not the Same Thing

woman whose holding her mouth - are canker sores and cold sores the same

Canker Sores and Cold Sores Are Not the Same Thing

Canker sores vs. cold sores: what’s the difference? Aren’t they the same thing? Not at all. One type of sore is highly contagious, while the other isn’t contagious at all. One occurs inside your mouth, while the other affects your lips and face. Here’s how to tell which one is which, and the appropriate treatments for each of them. 

How to Tell the Difference Between Canker Sores and Cold Sores


1: Location

The first thing to look at is the location of the sore. If the sore is INSIDE your mouth it is a canker sore. If it is OUTSIDE your mouth it is a cold sore. If the sore is on your lips, you can tell what type of sore it is by its color and texture.

2: Color and Texture

Canker sores are typically white, however they may also be yellow. Canker sores are also open and indented. If you were to touch it (which we do not recommend, it will hurt) the sore would dip in, almost like someone spooned part of your mouth out. 

Cold sores have several looks. At the start, a cold sore often looks like a pimple. They may be red, white, or even a lighter shade than your surrounding skin tone. Tender to the touch, you must resist popping them, especially at the later stages, because that could spread the sores to other parts of your face or to other people. Cold sores will start to fill with puss and become bigger as this fluid fills the area. Commonly it will look like many little pockets stuck together in a larger area. The tops look greyish white, with red surrounding the area. 

Canker Sores vs. Cold Sores

Canker Sores: These aphthous ulcers are painful sores that are normally white or pale yellow. They typically form on the inside of your mouth, most commonly on the cheeks, gums, and tongue. Canker sores are NOT contagious.

Cold Sores: Commonly known as “fever blisters” these are painful, fluid-filled blisters. They are typically found on the outside of the mouth, close to the lip line. Cold sores are VERY contagious.

What Is a Canker Sore? 

These small ulcers inside the mouth are a painful problem to have. Unfortunately, researchers cannot pin down specifically what causes a canker sore. They are not contagious, so they are not spread by kissing, sharing utensils, or sharing drinks. Many of the triggers for canker sores are nutrient deficiencies (B12, folic acid, and iron) stress, smoking, or minor injuries (such as accidentally biting your cheek). 

How to Treat a Canker Sore:

  • Gargle with salt water—the salt water helps to kill germs and numb the area.
  • Brush your teeth carefully—avoid the soft tissues around the sore to avoid pain.
  • Stick to soft foods—eating soft foods can help you avoid painful meal times.


What Is a Cold Sore?

These pus-filled sores on the outside of your mouth can be painful and cause many people to feel self-conscious. They are caused by an infection called herpes simplex virus. Researchers estimate that nearly 90% of adults in the U.S. have been exposed to herpes simplex virus because of its high level of contagion and its ability to hide. Many people do not ever show symptoms as this virus will sometimes reside in the nerve cells and only periodically reactivate. 

Cold sores can look different for children, and even be deadly for babies under 6 months old. If you think you have a cold sore, it is important to avoid touching your face and then touching your child, and to avoid kissing their skin until the blister has healed. If you think your baby might have a cold sore, contact their doctor for advice. 

How to Treat a Cold Sore:

  • Do not share your food or drinks—cold sores can spread to other people quickly.
  • Keep the area dry, and cover the blister if broken—the fluid inside the sore is what makes it contagious.
  • Use a cold sore medication—these can help dry up the sore and make it heal more quickly


Dental Care You Can Count On

Caring for your dental health means caring for your entire body. Both of these types of sores can be kept at bay by managing your stress and taking care of your body with good nutrition. Proper dental care is another important part of managing your health. 

Our goal at Hicks Dental Group is to provide you with dental care that shapes your life in positive ways. We know the importance of loving your smile. If you’re looking for a better dental experience, contact us today to make an appointment.




Images used under creative commons license – commercial use (1/21/24). Photo by Andrea Piacquadio.