Are Canker Sores Herpes?

I’ve spent a lot of time on this blog and on my email list trying to dispel the rumor that canker sores are caused by herpes. Anybody who’s had recurrent canker sores at some point in their life has had to deal with it. Either a comment from a friend or coworker, a sneering from a romantic interest, even doctors can be misinformed.

I’ve written on the blog, in my ebooks, and in many places that herpes and canker sores are completely unrelated. Some people who do get canker sores and who have Herpes Simplex swear that their outbreaks of canker sores and cold sores happen at the same time, and my argument has always been that the herpes flareup stresses the immune system, which brings about the canker sores.

I still believe this.

But one of the miracles of the internet is the ability for people to connect and share information and ideas, and recently I was contacted by a gentleman out of Chicago named Charles Tannenbaum, DDS, who is not only a dentist but also an Oral Pathologist…

Which is to say he knows what he’s talking about.

And Charles was kind enough to share some information with me to shed a little bit of light on the herpes/canker sores connection, so now I’m sharing it with you.


Herpes vs. Canker sores. It’s not herpes… Unless it’s herpes.

The prevailing wisdom that I’ve been espousing has basically boiled down to two points:

1) Canker sores always occur inside the mouth, and cold sores (Herpes Simplex) only occur outside the mouth around the lips.

2) Herpes-related cold sores pop up as a fluid-filled blister, while canker sores erupt as inflamed craters.

As it turns out, I was right about most of this, but there are some exceptions that are important to point out.

Herpes lesions CAN actually occur inside the mouth, but they present much differently than regular canker sores. Herpetic ulcers have 2 basic attributes to look for: clusters, and location.

Herpetic ulcers appear in the mouth much as they do around the lips, which is to say in tight clusters. The ulcers themselves are small, but can form in clusters of 3 or more.

They also are much more likely to occur on what are called the “attached gingiva”, which are areas like the gums and the hard palate at the roof of the mouth.

For the record, the herpetic sores that occur in the mouth go by a few names, such as Herpes Simplex Ulcers, Intraoral Herpetic Lesions, or Herpes Type 1 Ulcers, while the cold sores we’re more familiar with that occur on the lips are known as Herpes Simplex Labialis. Many doctors refer to the overall condition as Recurring Intraoral Herpes, or RIH.

The location is far less important than the clustering. While typical aphthous ulcers can appear as single or multiple ulcers, herpetic ulcers always occur in clusters.


Herpetiform ulcer confusion

In previous posts and in the ebooks, I classified canker sores into 3 categories: Minor, Major, and Herpetiform.

Minor aphthae are what we usually associate with canker sores and are by far the most common, accounting for roughly 80% of all ulcers. These are obviously smaller, at a centimeter in diameter or less.

Major aphthae are, thankfully, much less common, occurring about 10% of the time and grow to a centimeter and larger (to hideous proportions), often associated with severe immune suppression from drugs or immune system diseases like HIV/AIDS.

And finally, Herpetiform ulcers, which are the least common, at only 5-10% of ulcers, which present in clusters.

As I’ve just mentioned, clusters are the main characteristic of herpetic lesions, and the “Herpetiform” label certainly seems to imply that they are caused by herpes, right?

But that would be too simple now, wouldn’t it?

Here’s where things get fun. The term “Herpetiform” is used to denote the way the ulcers are presented, not the cause. The clustering of the ulcers appears much like the clustering of cold sores on the lips as in Herpes Simplex Labialis, and so the term “Herpetiform” came to be used to describe ulcers that appear in clusters. It was not used to describe the cause, even though clustered ulcers can be indicative of herpes.

This is where some legitimate confusion does take place. Herpetic ulcers related to Herpes Simplex 1 do tend to present very much like the Herpetiform type of aphthous ulcer, which has nothing to do with herpes. And just for fun, they sound just the same.

Somewhere out there is a medical terminologist laughing maniacally at all of us. (Note: I may have just totally made up the term “medical terminologist”.)


Other herpes and canker sores differentiation

“Great, I get them in clusters, so is it herpes?”

It’s very possible. Luckily, there are a few more defining characteristics that we can examine to tell if the sores are herpetic.

1. Vesicles  This can be more difficult to determine in the mouth, but herpes lesions always begin as fluid-filled blisters, or vesicles. Aphthous ulcers will very rarely (as in practically never) show up this way.

2. Size  Herpetic ulcers generally are much smaller than aphthous ulcers. But again, occur in clusters.

3. Ulceration  Canker sores, once they erupt, tend to be mostly white on the inside with a “red halo” surrounding the ulcer. Herpetic ulcers tend to be more red throughout, though they can ulcerate to white in the middle.

 4. Location  While not a rule that’s carved in stone, generally herpetic ulcers occur on the “attached gingiva”, meaning the hard palate on the roof of your mouth and the gumline. Herpetiform ulcers can also occur in those places, but if you’re seeing clusters in other parts of your mouth like the tongue, cheek, and floor of the mouth, it’s likely not herpes.

5. History  If you’ve EVER gotten a cold sore – meaning a fluid-filled blister on your outer lip – it’s very likely a herpetic ulcer.

Really, the best way to understand the difference is to see them. Now, I have a pretty die-hard rule against showing pictures of ulcers on this site, but I don’t mind linking away to this PDF that Dr. Tannenbaum was kind enough to share with me. There’s actually plenty of fantastic information on there and a few pictures that make it even more clear.


What to do if you have herpes lesions.

“Dammit,” you say. “It’s herpes. Now what?”

First off, calm down. It’s not the end of the world. You’ve got a virus that’s shared by roughly 70% of the population. Seriously. Fewer people drank water today.

But it is something you should see a doctor about. He or she may prescribe prescription medication such as Acyclovir, Valacyclovir, or Famciclovir. They may also prescribe topical gels or mouthwashes containing antihistamines to help relieve the pain and speed healing. Steroidal pastes, which are very successful with aphthae, are generally avoided with herpetic ulcers.

And beyond that, it’s just a matter of waiting a couple of weeks for them to go away. The biggest bummer with herpetic ulcers, as with cold sores, is they are contagious. So be careful with loved ones when you’re experiencing an outbreak. Keep mouth contact to a minimum.

Finally, to sum it up:

Single ulcer less than 1 cm across = canker sore

Single ulcer larger than 1 cm across = really bad canker sore

Cluster of ulcers on or under the tongue or cheeks = probably canker sores

Cluster of ulcers on the gums or roof of the mouth = probably herpes

Cluster of ulcers that began as tiny blisters = herpes

Cluster of ulcers when you also get cold sores = herpes

A big thanks to Dr. Charles Tannenbaum for sharing this information with me, and I’ll be sure to update the other pages of the site to reflect this clarification.

To your pain-free future.

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