Canker sores vs. Herpes?

What is the difference between Canker sores and herpes? How can you tell which is which? Are they both contagious?

[Alan Rockoff, MD]

John:

Canker sores occur inside the mouth or on the tongue or gums.  They are presumed to be viral, but no one knows for sure.  They are not contagious.

Herpes generally occurs outside the mouth, at the lip margin.  Only once in a while do people get the severe primary attack, in which there is 103 fever, swollen glands, ands bleeding gums.  Until it dries up, herpes is contagious by direct contact.

Hope this helps.

Dr. R

[Chris Martin]

This is just bad advice.  Oral Herpes can be contagious even when no symptoms are present.

[Alan Rockoff, MD]

What then would you advise someone who once had a cold sore but has no active leion?  That they never kiss anyone for the rest of their lives because of a theoretical chance of transmission?  If you think that would be good advice, then we will have to agree to disagree.

Dr. Rockoff

[Rosalita]

Thank you Dr. Rockoff!!

[Tim]

Is there a possibility that canker sores turn into/contribute to the cause of genital herpes?

[sven (2nd yr med student)]

Is it correct that herpes inside the mouth only occur on the hard palate (roof of mouth) and gums.  Herpes does not occur on any soft palate tissue, such as the tongue or inner cheek area.