Canker Sore Primer Part 2: Myths vs. Reality

RAS is a condition that over the years has spawned a lot of myths and misconceptions, for a variety of reasons.  From the fact that it exhibits symptoms that are similar to other diseases, to the fact that it affects different people in different ways, to the fact that there’s never been a lot of scientific study put into the condition, at least nothing that has gotten any attention by the mainstream press.

So let’s bust these myths here and now.  Keep in mind, that as with anything medical, there are always exceptions to the rule.  But the rule is the rule for a reason – because it’s the most common scenario.


Myth:  Canker sores are herpes.

Reality: No.

No no.

No no no no.

No no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no.

I can’t stress this point enough.  Canker sores… are not… caused…. by…. herpes.  Period.

I grew up most of my life believing that I had herpes of some kind, convinced I would never find a woman who would understand and be willing to risk getting it herself, at the same time very confused as to how I was suffering the symptoms of a venereal disease when I was 8 years old.  All misconceptions all the way around.  (Not only did I not have a herpes virus, but herpes simplex is spread in all kinds of ways that have nothing to do with sexual activity.  It’s no more salacious than the common cold.)

I covered all this in Part One, but it’s worth repeating.  The herpes simplex virus is the cause of cold sores and fever blisters, which are completely different from canker sores.  Cold sores start as fluid-filled blisters around the lips and outside of the mouth, which then burst and scab over.  They very rarely occur inside the mouth.  Canker sores, however, do not start as blisters, they are concave craters that form in the mucosa of the inside of the mouth and usually start as a trauma of some kind – sometimes so small they can’t be seen.  And they do not scab over as cold sores do.

The main cause of RAS is a faulty immune system response, not related to any kind of bacteria or virus, though it can be a symptom of a stressed immune system caused by a virus or infection.


Myth: Canker sores are contagious.

Reality: Again, no.

This clearly coincides with the herpes myth, as cold sores and the herpes virus are contagious, but canker sores are not.


Myth: Canker sores can be spread to the genitals during oral sex.

Reality: No.  And eww.

Once again the shadow of the herpes persists.  As far as I know there are no clinically documented cases of anyone having canker sores on their genitals, though there are various diseases, like Behçet’s Disease, for example, that cause sores down there that resemble canker sores, but they’re not the same thing.


Myth:  Stress causes canker sores.

Reality:  Yes and no.

There are mountains of anecdotal evidence of people who have had increased number of canker sores during stressful periods.  There are also mountains of anecdotal evidence of people who have seen no difference whatsoever.  I for one have never seen a major correlation between stress and canker sores in myself anyway, though many canker sore sufferers I know say the exact opposite.

While I’m never going to disagree with anyone’s own findings, I’ve always felt that the stress = canker sores thing has been another misconception confusing mouth ulcers with stomach ulcers, which for most of medical history people have blamed on stress.  But even that has come under suspicion in the last 10 years since the discovery of the Helicobacter pylori bacteria, which most gastroenterologists believe is the main cause of stomach ulcers (and some even believe it may play a part in RAS… more to come).

Having said all that, in either case, it all comes back to the immune system.  A person under stress is likely going to have a more suppressed immune system due to our body’s fight or flight response, which reacts to stressors by shutting down systems that are not essential to surviving the fight or flight.  The immune system is one of those systems.  So in stomach ulcers, it allows the Helicobacter pylori bacteria to thrive and cause ulcers.  In RAS, it causes the immune system to attack the lining of the mouth.  So that’s the evidence that we know.


Myth: Smoking cures canker sores.

Reality: Actually… sort of!

What the studies have shown is that smokers with RAS who quit smoking have often started getting ulcers, which then went away when they started smoking again.

Yeah… Weird.

Of course, this doesn’t mean that smoking is good for you and you should go out and do it.  It could also be argued that the smoker who has stopped smoking was under a lot of stress because of it, which then brought on the you-know-what.


Myth: Canker sores are a symptom of AIDS.

Reality:  Yes, this is true.

Again, this goes back to the immune system.  The name AIDS stands for Acquired Immune Deficiency Syndrome, which opens the patient up to all kinds of maladies from their weakened immune systems.  Canker sores are one of those maladies.  It is also a symptom of several other autoimmune and immunodeficiency diseases for the same reason.  People undergoing chemotherapy also experience canker sores.

But remember, correlation is not causation.  If you have a canker sore, it does not mean you have HIV.  Though it’s never a bad idea to get tested, it’s no reason to freak out.


Myth:  RAS is hereditary.

Reality:  Yup.

Just ask my mom and my sister.


Myth:  It’s brought on by a vitamin deficiency.

Reality:  Possibly.

Studies have shown that severe deficiencies in iron, vitamin B12 and folic acid can help bring on the symptoms, though these are more rare than we think.  L-Lysine supplementation is also recommended.  Keep in mind with any kind of supplementation, it takes a long period of time to see effects.


Myth: It’s a government conspiracy.

Reality:  I can neither confirm nor deny that.


Continue your primer below!

Mouth Ulcer Roadsign


Mouth Ulcer Road Sign


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