Can You Go In The Sun With A Cold Sore?

I remember, back in the day, when I was younger and my immune system was weaker, I would get cold sores across my entire upper lip! I would often feel that slight itch across my lip just before going to bed, and I knew I was in for a nasty surprise the next day.

And I was usually right…

Can you imagine waking up for school, getting in front of the mirror and seeing your entire upper lip covered in blisters and scabs?

Not only was my day ruined, I knew a long, gruesome week of cursing my life was about to start…

But back then, I honestly didn’t know sun exposure played a role in all of this, not only causing my cold sores but making them worse as well. Fortunately, I came across some interesting research which I’m about to share with you today.

But, back to the question at hand: Can you go out in the sun with a cold sore?

Studies suggest that sun exposure will increase the number of viral particles found in your skin, increase the number of lesions and their severity. In other words, sun exposure will make your cold sore more severe and prolong its treatment.

So, no, you should not go out in the sun if you have a cold sore.

How Does Sun Affect Cold Sores You Already Have?

I struggled a lot to find a good, scientifically-backed answer to this question. The articles I came across would usually talk about sunlight as a cause, but what about those who already had cold sores? How did the sun affect them?

The first study I came across measured the effect of UV radiation on the skin associated with herpes simplex virus in rats. It showed that exposing the skin right after the HSV (herpes simplex virus) infection increased the severity and the number of cold sores.

A different study showed that exposing the affected skin to UV radiation enhanced viral titres. Viral load, also known as viral titre or titer, represents the number of viral particles in a given volume.

Simply put, if you go out and expose your skin to direct sunlight, your cold sores will become more severe, the number of scabs will rise, the breakout will last longer, and be more difficult to treat.

Does Sunlight Cause Cold Sores?

Sunlight is actually only one of the triggers; cold sores might be triggered by everything from fatigue to stress, but it is important to point out that cold sores are caused by a herpes simplex virus type 1 (HSV-1) usually due to weakened immune system.

Most HSV-1 infestations are acquired during childhood and are lifelong, unfortunately. It is estimated that 3.7 billion people (67{285d6d0ec33f832d63ba71e7361dfa254e621171fe0222a0c97ebd34aa916c6a} of the entire world population) have HSV-1.

So, can the sun cause primary herpes? Most likely not because the condition is caused by a virus, but sun exposure will lead to the development of cold sores as a result of recurrent herpes simplex.

There are three main pathways through which sunlight impacts HSV recurrence:

Whichever the path may be, sun exposure is well documented as a significant factor in recurrent HSV and the appearance of cold sores. One of these well-documented cases is a study  done at the Osaka Sun Clinic and Sun Care Institute.

This study showed that sun exposure is responsible for 10.4{285d6d0ec33f832d63ba71e7361dfa254e621171fe0222a0c97ebd34aa916c6a} flare-ups in test subjects. What’s even more interesting is that this number jumps from 10.4 to 19.7{285d6d0ec33f832d63ba71e7361dfa254e621171fe0222a0c97ebd34aa916c6a} when we look at the data concerning only the summer months (July and August).

Not only that, looking at the patients under 30 years old, during these summer months, we see that the total amount of sun-induced flare-up are present in 40{285d6d0ec33f832d63ba71e7361dfa254e621171fe0222a0c97ebd34aa916c6a} of these test subjects. The study clearly shows the connection between cold sores and sun exposure.

Treating Sun-Induced Cold Sore Outbreak

When I get a cold sore, I want the ground to open up and swallow me, or to remain housebound until it disappears! Unfortunately, this is not possible and the only way to get back to normal activity is to speed up the healing process.

There are several different courses of treatment we can take:

Using topical antiviral agents, such as acyclovir, showed some promising results but its effectiveness is yet to be determined in shortening the duration of the cold sore and reduce the severity of the outbreak.

The evidence is mostly anecdotal and results may vary from patient to patient.

Preventing Sun-Induced Cold Sore Flare-Ups

Obviously, the best way to prevent and manage cold sores is to avoid sunlight… this is, of course, not possible but what we can do is protect our skin for harmful UV rays.

Sunscreen And Sunblock Sticks

It makes sense that we’ll prevent sun-induced cold sores by applying sunscreen, but is it always the case?

A study done at the Laboratory of Oral Medicine at Bethesda followed a group of 38 test subjects that were exposed to UV light in an area of a previous labial herpes occurrence.

The trial was done in two sessions – before the first session, sunscreen was applied to the lips while the placebo was used for the second one.

The results were more than conclusive, the placebo session had 71{285d6d0ec33f832d63ba71e7361dfa254e621171fe0222a0c97ebd34aa916c6a} cold sore recurrence while sunscreen had 0!

Another study set out to assess the effects on a sunblock stick in the prevention of solar-simulating UV light-induced herpes labialis. And, once again, the results were clear – out of 19 patients, 11 had a herpes recurrence while only one had a recurrence with the sunblock stick.

General Prevention Tips

First things first, always make sure that you have the right medication to hand so that if you ever feel as if you are getting a cold sore, you have something to attack it with. It is also handy to become familiar with what triggers cold sores for you, everyone is different; however, here are some of the most common:

Here are some steps you can take to prevent cold sores from coming back: