Canker sores, cold sores, and mouth sores: What’s the difference?

Many people have had an experience of some form with mouth sores or irritation, and we understand that at Well Family Dentistry. We can also tell you that some mouth sores are harmless and will go away on their own after a few days, while others are more serious and should not be ignored. There are many different reasons for mouth sores, but they are trigged by bacterial infections, viruses, or funguses. The easiest way to tell the difference between the different sores is by their location. Canker sores occur inside the mouth while cold sores occur outside of the mouth.

The most common mouth sores are:

Canker sores:

This small, grayish ulcer with a red border is non-contagious and appears inside the mouth. It can develop from outside factors like stress, fatigue or allergies, but most health experts believe they stem for a virus or bacteria that attacks the immune system. Canker sores normally heal within a few weeks. .

Cold sores:

Also known as fever blisters, they are contagious groups of fluid-filled blisters that normally show up around the lips, under the nose or around the chin. Cold sores result from the herpes simplex virus, and once infected, the virus will remain in the person’s blood steam.


This is a premalignant lesion that appears as a white patch on the inside of the mouth, tongue or gums. Leukoplakia is a potential warning sign of oral cancer. The lesions normally affect those who smoke tobacco and are caused by excessive cell growth. Dr. James Wells may choose to have the lesion biopsied if it appears to be severe.

Oral candidiasis:

This is commonly known as oral thrush or moniliasis, and is caused by the overgrowth of candida yeast. Symptoms of oral candidiasis include white spots inside the mouth and on the tongue, discomfort or redness in the mouth area, cracking at the corner of the mouth, sore throat and difficulty swallowing. It is important to visit Dr. James Wells and our team at the Wells Family Dentistry if you have symptoms of oral candidiasis. If it is left untreated, it can be very dangerous and may infect your bloodstream. The condition is most often seen in infants, elderly, people with AIDS or other diseases that are known to weaken the immune system or those undergoing chemotherapy. It is not normally found in healthy adults.

If your mouth sore lasts a week or longer, please give us a call and schedule an examination at our Morehead City, NC office.

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