Difference Between Cold Sore and Canker Sore

Main Difference – Cold Sore vs Canker Sore

Cold sores and Canker sores are two different types of lesions which can develop in the body due to various etiological conditions. However, these terms are often used interchangeably by most of the people, probably due to lack of clear knowledge about the different features owned by each of them. The main difference between cold sore and canker sore is their location; cold sores are generally seen outside the mouth and around the lips whereas canker sores develop inside the mouth.

In this article, we are going to discuss

1. What is a Cold Sore? – Clinical Features, Cause, Spread, Diagnosis, Treatment

2. What is a Canker Sore?– Clinical Features, Cause, Spread, Diagnosis, Treatment

3. What is the Difference Between Cold Sore and Canker Sore?Difference Between Cold Sore and Canker Sore - Comparison Summary

What is Cold Sore

Cold sores, also known as fever blisters or lesions of herpes simplex type 1, are a group of painful blisters which typically appear outside the mouth, around the nose and lips or under the chin.

These can get acquired easily after the exposure to someone who has already got the condition through direct contact or by kissing or sharing personal items. Furthermore, healthcare workers like dentists and respiratory therapists are at a high risk of developing herpetic whitlow with cold sores due to possible contact with patients with this contagious condition.

Poor immunity-HIV/AIDS, malignancies, steroid therapy, can also precipitate cold sores as a result of the declining ability of the body to fight against pathogenic organisms.

Patients with cold sores will usually complain of a tingling and itching sensation around the lips at the initial stage which will ultimately give rise to oozing and crusting with pain.

Being a clinical diagnosis, cold sores usually resolve spontaneously in about 2-4 weeks without any treatment.

However, certain antiviral drugs may help to fasten the healing process whereas pain relieving medication can be taken if the pain is unbearable.

Difference Between Cold Sore and Canker Sore

What is Canker Sore

Canker sores, thought to be caused by a virus (not very evident), are a group of small, shallow ulcers which usually appear inside the mouth which often make eating and talking very uncomfortable.  

Even though the major causative agent is not clearly evident, viral organisms entering into the oral cavity following minor injury to mouth  – during dental work, aggressive brushing, accidental cheek bite, harsh toothpastes and mouth rinses containing sodium lauryl sulfate, various food like chocolate, coffee, spicy or acidic foods, a diet lacking vitamin B-12, zinc, folate or iron and emotional stress are known to be playing major roles in the initiation of pathology behind canker sores. 

Canker sores can also be seen in patients with Celiac disease, inflammatory bowel disease (Crohn’s disease and ulcerative colitis), autoimmune conditions and HIV/AIDS, which suppresses the immune system.

These lesions will appear round or oval with a white or yellow center and a red border and develop inside the mouth or under the tongue, inside the cheeks or lips, gums or on the soft palate.

Initially, there will be a mild tingling or burning sensation after which sores appear in about 2-3 days.

In most of the patients, canker sores will resolve on its own without treatment. It is important to refrain from eating hot and spicy foods which can result in pain. Using over-the-counter mouthwashes or salt water preparations will also help in a quick recovery.

Main Difference - Cold Sore vs Canker Sore

Difference Between Cold Sore and Canker Sore


Cold sores, also known as fever blisters, are caused by herpes simplex virus and can get triggered by stress, trauma, and exposure to extreme conditions.

For canker sores, there is no clear etiology to occur and are known to get triggered following facial trauma, stress, and hormonal changes.


Cold sores are generally seen outside the mouth and around the lips.

Canker sores develop inside the mouth, at the base of gum and inner cheeks, making eating and drinking so uncomfortable.


Cold sores usually appear in clusters, red in color and fluid filled.

Canker sores are comparatively smaller with a white-gray center and a red border. They can present either as single lesions or groups.


Cold sores are highly contagious and the virus can spread from skin-skin contact.

Canker sores are not contagious at all according to latest literature.


Both sores will resolve spontaneously over time, but anti-virals might have an effect on cold sores if the underlying agent has found to be Herpes simplex virus. Pain relief and oral cleansing with salt water or a mouthwash are recommended for both conditions.

Image Courtesy: 

“Aphtha2” By Photographer: User:TheBlunderbuss – Own work. Published under GFDL in English Wiki (CC BY-SA 3.0) via Commons Wikimedia

“Herpes(PHIL 1573 lores)” (Public Domain) via Commons Wikimedia 

About the Author: Embogama

Embogama is a passionate freelance writer for several years. Her areas of interest include general medicine, clinical medicine, health and fitness, Ayurveda medicine, psychology, counseling and piano music