The most common cause of cold sores is the HSV-1 virus.  This virus is contracted by most Canadians during childhood or adolescence and the vast majority of adults, up to 80%, are seropositive for HSV-1, but often without symptoms.  For those who develop occasional cold sores, episodes tend to be mild and self-limiting, but the impact on quality of life can be significant for those with frequent recurrences.  There are a number of common misconceptions about the cause, transmission and treatment of cold sores.  


Myth: All those exposed to the HSV-1 virus will develop recurrent cold sores 

While HSV-1 is highly contagious, less than half of patients, an estimated 20% to 40%, develop recurrence following exposure to the virus and primary infection.  Following an initial infection with HSV-1, the virus moves along to the nerve tracks from the mouth lining to the nerve cell bodies for future viral attack.  Upon reactivation, the virus spreads from the infected neurons to the mouth region.  For those who do develop recurrences, the frequency ranges from one to six times annually. 

Myth: Recurrence of cold sores is seasonal 

One common misconception is that cold sores only occur in winter and following a cold or flu.  While recurrence of cold sores often relates to immune status (hence the association with a cold or flu), a number of other factors relate to cold sore recurrence such as fatigue, stress, extreme temperatures, both hot and cold, hormones and trauma to the mouth.   Some triggers are avoidable, so education around common triggers can potentially reduce the rate of recurrence.  

Trigger Factors of Recurrent Cold Sore Infection 

- Fever
- Ultraviolet light exposure
- Viral upper respiratory infection 
- Emotional stress
- Fatigue 
- Trauma 
- Iron deficiency 
- Oral cancer therapy 
- Oral and facial surgery 
- Viral infections 
- Menstruation 

Myth: HSV-1 is only transmitted when blisters are present 

It is important to be aware the HSV virus is highly transmissible when blisters are present through contact with active lesions, respiratory drops, contaminated inanimate objects and secretions, - the virus is also transmissible in the “prodromal stage” (a tingling sensation that may occur up to five hours prior to development of blisters).   Generally, there is a risk of transmission until the lesions crust over entirely and up to 60 hours after the onset of symptoms.   

Myth: Cold Sores Will Not Spread Beyond the Lips 

While the HSV-1 virus mainly affects the lips or mouth, it can spread to the nose, eyes and possibly to the genital region.  People should be advised to avoid touching the lesion and to wash their hands after application of a treatment product and frequently throughout the day to reduce the risk of spreading this virus.  

Myth: None of the Over-the-Counter Treatments for Cold Sores Speed Healing 

There are a number of over-the-counter products and home remedies suggested for the treatment of cold sores, and it is true that many lack evidence of efficacy.  Home remedies include applying tea bags, vinegar and ice to the lesions.  Tea bags and vinegar are largely ineffective.  While ice can provide symptomatic relief by reducing swelling and pain, it does not speed the healing process.  Applying alcohol or witch hazel to a cold sore may dry out the lesions, but these products do not speed healing.  Further, products that contain counter irritants (e.g. camphor, menthol and phenol) can provide some symptomatic relief, but do not shorten the duration.   

Docosanol cream (Abreva) is an over-the-counter treatment for cold sores that has been shown to reduce the healing time by 1.6 to 4.6 days and shorten the duration of pain symptoms.  The cream is applied 5 times daily for 10 days to the lesion and the immediate skin surrounding the lesion.  Unfortunately, it is quite expensive.  There are several prescription products that your family physician can utilize where appropriate. 


There are many misconceptions about the HSV-1 virus and cold sores.  While the HSV-1 virus is highly contagious, not all those exposed will develop recurring lesions.  However, for those that do, cold sores can be a source of distress, particularly when recurrences are frequent.  Non-prescription and prescription options are available.  Talk to your pharmacist and/or physician for the best option(s) for your personal treatment!  

Norm Corriveau, B.Sc.Phm, Pharmasave Smith Drugs

(Seven references available upon request) 

Tips from your pharmacist 

- If you take more than one medication, use daily or weekly pill containers to help remind you when to take the medicine 
- If you have trouble opening pill bottles, ask the pharmacy to put your prescription(s) in a bottle with an “easy open” lid 
- If you are taking prescription medication and/or have a medical condition, always confer with your pharmacist prior to over-the-counter product selection