Cold Sore FAQs

Dr. Kyle Hornby

This week, I'm tackling frequently asked questions surrounding Cold Sores. Why do some people get them? Why do they recur? Can you prevent them? What's the best way to get rid of them? And, I'll answer many more questions along the way!

Let's talk about Cold Sores...

How do I know if I have a Cold Sore?

Cold sore or "Fever Blister" onset begins with a tingling or stinging/burning sensation in an area on the outer border of the lip. 1-2 days later, you'll notice an elevated red area followed by fluid-filled blisters days after that. These blisters may spread to nearby areas around the lip so try to minimize direct contact with affected sites. Eventually, the blisters dry up and crust over.

How long do Cold Sores last?

From the onset of symptoms to complete healing, resolution of cold sores commonly takes 10-14 days.

How often do Cold sores appear?

I see some patients for cold sore treatment every couple of months. For other patients, they may experience a re-activation of HSV-1 and resulting outbreak of Cold Sores only yearly. For others, the frequency of these fever blisters is even less frequent.

What causes Cold Sores?

Cold sores are caused by Herpes Simplex Virus 1, or HSV-1. Don't feel bad. A majority of the population harbours HSV-1 but only a percentage suffer from cold sores. For those who suffer from these sores or , HSV-1 is dormant most of the time. When the virus becomes active, the Sores re-surface.

In some individuals, HSV-1 never becomes active...and they, never experience cold sores.

What factors allow HSV-1 to become active?

As I mentioned above, Cold Sores or "Fever Blisters" start when dormant HSV-1 becomes active. This happens when your immune function takes a dip. Factors that can lower your immune function can include:

  • lack of sleep
  • extreme stress
  • poor diet
  • systemic conditions affecting your immune system (i.e. Diabetes, HIV, etc.,)

Are cold sores contagious when kissing?

Yes. It is best to avoid contact with others as much as possible from the time that symptoms of burning and tingling start to when blisters dry out and fully heal.

Can the sores spread around the lip?

Absolutely. This is very common and can occur during the raised red lesion phase or during the fluid blister phase. Do your best to avoid making contact with your lips during sore re-activation.

Why do Fever Blisters keep coming back?

Cold Sores are caused when dormant HSV-1 becomes active. You cannot rid yourself of HSV-1 once you have it. Because of this, your best chance at preventing re-activation of HSV-1 and the ensuing Cold Sores is to keep your immune function at peak levels!

How can you improve Immune System function?

Your immune system performs at Olympic-level efficiency when you are at your best. This includes getting an appropriate amount of sleep. Avoid physical and mental exhaustion. Eat well. Fuel your immune system with a diet of whole foods that is chalk-full of vitamins, minerals, and high-quality fats. Consider use of probiotics. Ginseng supplements and Garlic Extract can also help.

What Cold Sore medicine is best?

There are 2 common options here including Docosanol creams (like Abreva) and Anti-viral meds (either topical or systemic). Systemic anti-virals come as pills that you eat while the topicals are creams and ointments that you can apply.

Abreva (a non-prescription cream) is effective at drying out sores and minimizing pain. Anti-virals are effective directly against HSV-1. The systemics are most effective but topical ointments can help, too. The most common Anti-Virals used to fight cold sores are Valtrex and Zovirax. You need a prescription from your Family Doctor or Kitchener Dentist for these items.

Does Laser Cold Sore Treatment work?

Laser treatment for Fever Blisters is controversial in terms of efficacy. Many Dentists support the use of laser treatment citing decreases in pain and faster healing as benefits. Theories exist that laser treatment can stimulate healing of sores through increases in collagen production. Other Dentists suggest that Laser Treatment can disrupt HSV-1 activity.

By Dr. Kyle Hornby, Dentist in Kitchener, ON

Our Kitchener Dental Office is conveniently located in Downtown Kitchener and we are a short drive away for families in Waterloo, Breslau & St. Jacobs. Our central location means we truly offer family dentistry near you!

This article is meant to promote understanding of and knowledge about general oral health topics. It is not intended to be a substitute for professional advice, diagnosis or treatment. Accordingly, always seek the advice of your Kitchener Dentist or other healthcare provider regarding a dental condition or treatment.

Enjoy a fresh start.
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