Skip to main content
Cold Sores: Causes, Treatments, and Prevention

You are listening to Health Library:

Cold Sores: Causes, Treatments, and Prevention

Jul 07, 2023

Cold sores are caused by the Herpes Simplex 1 virus, which resides in nerves near the spinal column. These sores are painful and persistent, and once the virus infects the body, it never goes away. Tom Miller, MD, discusses triggers and causes of cold sores, as well as the importance of oral treatments during the prodromal stage to alleviate symptoms.

Episode Transcript

Interviewer: They are gross, they're disgusting, they hurt, they look terrible. I am talking about cold sores. Dr. Tom Miller with University of Utah Hospital. We are going to talk about what causes it and maybe what you can do to get some relief and get that thing off your face.

So, cold sores. What exactly is going on and how did I get it in the first place? That's what a lot of people wonder.

What are Cold Sores?

Dr. Miller: Cold sores, Scot, are due to a common virus called Herpes 1 simplex virus. Herpes simplex 1.

Interviewer: Is that the same herpes? Is that the same herpes as the other herpes we hear about?

Dr. Miller: It is. It's a slightly different type of virus but essentially, the two are the same. The one we are talking about today is commonly referred to as herpes labialis or the common cold sore that people get on their lips. And for aesthetic reasons, no one likes it.

Interviewer: They are ugly.

Dr. Miller: And they are painful.

Interviewer: Yeah.

Cold Sore Triggers and Frequency

Dr. Miller: And why do some people have those recurrences more than others? I don't think we quite know yet but certainly, there are some folks who have them very rarely and others who seem to get them more frequently.

Interviewer: So, I understand they actually live in the base of the spine.

Dr. Miller: They live in nerves near your spinal column. So, once the virus is...once you are infected by the virus, it stays. It doesn't ever go away. And for reasons that we are not entirely clear about but probably related to stress. Maybe too much sunlight, maybe too little sleep, maybe another cold. The virus will reactivate, travel down the end of the nerve, and result in that common cold sore that everybody hates to find out about.

Interviewer: So stress, compromised immune system.

Dr. Miller: And sometimes, it just happens. We are not exactly sure why.

Treatments for Cold Sores

Interviewer: And when it comes to the surface, is there anything you can really do? There are all sorts of products on the market that say work. Have you had experience with ones that actually do?

Dr. Miller: Most cold sores last around five days. Most people know when one is coming on. They'll have a tingling sensation, maybe a slight swelling in the lip. That's the time to begin treatment. The best treatments are the oral antiviral agents that are prescribed by physicians and other providers. Those work pretty well. They will generally reduce if you get them started quickly and especially in that prodromal time. That's the time before you can actually see the cold sore. They'll cut the time of the cold sore's presence by about two days and they can decrease the severity of the pain and the size of the lesion.

Interviewer: Do some of those medications actually keep them from breaking open or are you always going to have them break open?

Dr. Miller: Not necessarily. It may prevent it from breaking open. Typically, you'll see that little blister on a very red and raised base. It's painful and terribly ugly to most people. But it does resolve completely whether you use the antiviral treatment or not. I would say that the topical agents that you can buy over the counter have been shown to be not very effective.

Interviewer: Really? Like Abreva and that sort of thing?

Dr. Miller: Yeah, the topical agents have minimal effect on timed resolutions. So if you really want to decrease the time of the sores, there you need to use an oral medication or an oral antiviral agent, and there are a number of those on the market. There are a couple that are generic, that you need to take for a longer period of time. There are those that you can take one dose or two doses on the same day. It'll do the same thing as the generic version that's taken over five days.

Preventing Cold Sores

Interviewer: What about preventative steps? Like taking lysine, for example, eating almonds. Are those just myths?

Dr. Miller: They may work but we have no proof right now that they are effective. So, I don't disparage something that people think might be helpful but we just don't have any proof that those are working.

Interviewer: What about that is more of a symptom of a compromised immune system? If you get them a lot, could that mean that there is something else going on in your body?

Dr. Miller: That's possible. I think if you are having frequent attacks, meaning a couple of months or one month, you might want to see your physician to see if there could be some other reason that you might have these recurrences on a regular basis. There is chronic suppressive therapy, that's the same antiviral but it's taken daily and it's considered to be used... you can consider using it in folks who have four or more of these outbreaks a year and it's effective in suppressing recurrent herpes spots.

Interviewer: So if you have a cold sore, it's probably smart to avoid kissing from the moment it tingles until it's completely healed. What about sharing silverware glasses?

Dr. Miller: Yeah, I'd avoid doing that. Those are common sense things we do with all infections. We stay away from close personal contact and avoid using things that we've... drinking and eating utensils and wait until the cold sores are completely resolved.

They are common, they're troublesome but there is treatment to reduce the duration and if that's a problem for you, go ahead and talk to your physician about it. I would say that people can pick up a supply of antivirals that they could start. So if you have those on hand, if you have the prescription on hand, you can begin that as soon as you have the symptoms rather than wait to go to your physician. So, if you find that you are having several or a couple of these outbreaks a year, you might talk to your physician about giving you a supply of the antiviral so you can begin it as soon as the symptoms start. That gives you the best chance of cutting the duration.


updated: July 7, 2023
originally published: December 9, 2014