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Sorely Confused

What is the Difference Between Cold Sores, Canker Sores, & Chancre?

By Elizabeth Boskey, Ph.D., About.com

About.com Health's Disease and Condition content is reviewed by our Medical Review Board

People suffer from an array of sores on their mouths and their genitals, but there are three types of sores that by virtue of their names and locations are frequently confused. These are canker sores, the cold sores caused by oral herpes, and the chancre sores caused by syphilis.

1. Cold Sores

Photo courtesy of the CDC/ Dr. K. L. Hermann
Cold sores, or fever blisters, are caused by a herpes virus. These small painful blisters are most often found around the lips, and usually break open, crust over, and heal over the period of a week to 10 days. Cold sores are usually caused by HSV-1, the type of virus most often associated with oral herpes, but can also be caused by HSV-2, which is more often associated with genital herpes. Both types are extremely contagious, especially when active lesions are present, and can be transmitted by casual as well as sexual contact –- friendly kissing puts you at risk as well as anal, vaginal, and oral sex. Herpes transmission may also be associated with exposure to infected objects such as eating utensils and razors.

2. Canker Sores

Photo Courtesy of CDC/Sol Silverman, Jr., DDS (1999)
Canker sores are ulcers that occur in the soft tissues inside your mouth. Although they are associated with various nutritional and immunological deficiencies, canker sores are not contagious or sexually transmitted. They are, however, more common in individuals with acute HIV infection, because of its negative effects on the immune system.

Canker Sores, or apthous ulcers, are usually round white sores with a red border. Canker sores can remain painful for several days, but generally heal within one to three weeks. If you have a canker sore that is particularly large, uncontrollably painful, lasts longer than three weeks, or accompanied by a high fever, seek the attention of a healthcare practitioner.

3. Chancre

Photos courtesy of the CDC/Dr. Gavin Hart; Dr. N.J. Fiumara; Dr. Dancewicz
The round, usually painless, sore that is the first stage of a syphilis infection is known as a chancre. Although not usually found on the face, the similarity in names between "canker sores" and "chancre" has been known to confuse more than a few people. Primary syphilis chancre are most often found on the genitals, but they can also be found on the anus, mouth, lips, tongue, tonsils, fingers, breasts, and nipples.
Sources:

Cold Sores from The Mayo Clinic.

Canker Sores from The Mayo Clinic.

Syphilis from the CDC.

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