Sorely Confused: The Difference Between Cold Sores, Canker Sores, and Chancres

Cold Sores (Oral Herpes)

Cold sores (oral herpes) are small, painful blisters. They're mostly found around the lips. Over the course of a week to 10 days, cold sores typically:

• Erupt
• Break open
• Crust over
• Heal

Most cold sores are caused by the herpes simplex virus 1 (HSV-1). They can also be caused by HSV-2. But that type's more often seen in genital herpes.

Both HSVs are highly contagious. They're most contagious through an active sore. But herpes can be transmitted even when you don't have sores.

It's possible to get an oral herpes infection through sexual activity. But HSV-1 is more often picked up in childhood. For example, a child can get it from a parent's kiss. You can also get oral herpes from infected objects like eating utensils and razors.

Once you're infected with a herpes virus, it stays in your body forever. It may then cause outbreaks from time to time. Antiviral medications can suppress the virus and help prevent outbreaks.

The herpes virus doesn't cause chancres or canker sores.

Chancre Sores

Chancres are the first stage of a syphilis infection which is a sexually transmitted infection (STI). Syphilis chancres are most often on the genitals. They can also strike the:

• Mouth
• Lips
• Tongue
• Tonsils
• Anus
• Fingers
• Breasts
• Nipples

Chancres are round, firm, and usually painless. Because they don't hurt, they often go unnoticed. This is particularly true when they're in the mouth.

Without testing for syphilis, someone can be infected for a long time before noticing symptoms. Chancres clear up with antibiotic treatment for syphilis.

Oral sex plays a large role in the syphilis epidemic. That's due to chancres in the mouth.

Since chancre sounds much like canker, the terms are easy to confuse. But chancres are most often called chancres, while cankers are called canker sores. That can help you keep them straight.

Canker Sores

Canker sores (aphthous ulcers) are ulcers in the soft tissues inside the mouth. Canker sores are usually round and white with a red border. They can be painful for several days.

Their exact cause is unclear. Triggers may include:

• Stress
• Allergies
• Dehydration
• A weak immune system
• Minor mouth injuries
• Food sensitivities
• Genetics
• Hormonal shifts
• Various nutritional deficiencies (especially folic acid and vitamin B12)
• Some medications

Canker sores aren't contagious. But they're sometimes tied to contagious illnesses. For example, canker sores are more common in people with acute HIV infection. That's due to their weakened immune system.

Most canker sores don't need treatment. They generally heal on their own in three weeks or less. Serious sores or those that last extra long should be looked at, though.

Frequent canker sores can alert you to health problems. For example, they may be the first obvious sign of a nutritional deficiency or immune-related problem.