11 Surprising Facts About Cold Sores
by Carina Wolff

Many different things can come to mind when you think of cold sores, but with so much misinformation out there, it can be hard to separate fact from fiction. There are many surprising facts about cold sores that everyone needs to know, whether or not you have them. Clearing up misunderstandings can help you better understand cold sores, whether it's getting rid of the stigma attached to getting the virus, learning how to manage cold sores if you get, or figuring out how to prevent getting them in the first place.

Cold sores are caused by the herpes simplex virus, either HSV-1, which usually causes oral cold sores, or HSV-2, which tend to be genital. Cold sores often get confused with canker sores, but canker sores occur inside the mouth, and they're crater or ulcer-like sores triggered by stress, not HSV.

"Cold sores, also known as fever blisters, are usually caused by herpes simplex virus type 1 (HSV-1)," says Arefa Cassoobhoy, MD, MPH, WebMD medical editor, over email. For the most part, cold sores usually crop up on the lips or mouth. But they can show up in other places too."

The herpes virus isn't exactly a topic discussed everyday, so it can be useful to learn some new facts. Here are 11 surprising things everyone needs to know about cold sores.


Most People Have HSV-1


The biggest surprise? Most people already have the virus that causes cold sores. "About 2/3 of the world’s population has cold sores, or a strand of herpes called HSV-1," says Faisal Tawwab MD over email. As far as HSV-2 goes, a large number of people have that as well: 1 in 6, according to the Center For Disease Control (CDC).


It's Most Commonly Contracted In Childhood


Although many people do have the virus, not everyone gets it from sexual contact or kissing. "Most individuals are who contract herpes are first exposed to it as a child," says Dr. David Kulbersh, MD, Medical Director of, over email. "Think of all the sharing (and oversharing) tendencies children have — sharing drinks, eating utensils, slobbery kisses for everyone, etc."


Many People Don't Have Symptoms


It might come as a shock that so many people have the virus, but of those who have it, many don't realize it. "You would therefore be surprised to know that many who are infected don’t know they have it," says Tawwab. "Part of it is because symptoms, such as the sores themselves, don’t show up regularly. This makes tracking a 'breakout' difficult, if not impossible. This means that transferring an infection onto a partner is more likely because you can do so without showcasing an outbreak."


Cold Sores Can Appear In Places Other Than Your Lips


Coldsores aren't exclusive to just the lip region. "Although many cold sores are found at the region of the lip known as the vermilion border, they can also pop up at other locations such as around the nose and even on the tongue," says Nesochi Okeke-Igbokwe, M.D., M.S. over email. "The infection may potentially spread to the eyes if proper hygiene practices are not maintained when one has an active cold sore."


The Weather Can Trigger A Cold Sore


"Changes in weather, such as sun or wind exposure, may trigger the recurrence of a cold sore," says Okeke-Igbokwe. Abrupt changes in weather trigger your body's immune system, which increases your risk of developing a cold sore (if you already have the virus, of course).


Oral Herpes Can Be Spread To The Genitals & Vice Versa


HSV-1 is the referred to as the oral strain of herpes and HSV-2 as genital herpes, but cold sores in any location can be caused by either of the strains. "This means that if an individual with an active herpes infection around the mouth area performs oral sex on their partner, they can transfer whichever strain of herpes they have to their partner’s genitals, causing a case of herpes in the genital area," says Kulbersh. "Alternatively, if an individual has either strain of the herpes virus in the genital region, and their partner performs oral sex on them, their partner could get herpes orally caused by whichever strain their partner has genitally."


You Can Still Transmit The Virus Without A Sore


HSV lesions are most contagious when they are active, but the virus can still be transmitted without a visible sore. "Low levels of the virus can still be shed during inactive periods, meaning, you can still transmit the herpes virus to someone even when you don’t have an active cold sore," says dermatologist Tsippora Shainhouse over email.


You Can Have Symptoms That Predict An Outbreak

"Many people have a prodrome period immediately before the sore develops," says Shainhouse. "You can feel pain, itching, or tingling up to 1 day prior to the sore developing. It is associated with viral replication and nerve irritation. This is the time to treat with oral medications to prevent the sore from developing. If you can catch it early, you can hopefully prevent the blisters, or at least reduce the severity and duration of the episode."


The First Outbreak Is Usually The Worst


The first episode of a cold sore, called "Primary herpes gingivostomatitis," is usually the worst. "It's the most aggressive looking, the longest lasting, the most painful, and possibly the one that — due to discomfort — can interfere with eating," says dermatologist Robin Evans, MD over email. "This type of episode is more typically seen in childhood."


There's No Cure, But It Can Be Treated


Although there is no cure for HSV — it will remain in your body forever — that doesn't mean you have to suffer constant cold sore outbreaks. "There are prescription pills which can not only shorten the course of an active coldsore outbreak, but can prevent an outbreak from occurring in the first place," says Evans. "Treatment can be prescribed by your dermatologist."


The Stigma Can Be More Harmful Than The Infection Itself


"It is ironic that while so many people carry herpes, it has become a stigma..." says Tawaab. Many people get judged for not only their...appearance, but also for seeming 'unsafe,' 'reckless,' or 'slutty.' Because herpes isn’t yet curable, it’s something someone has to deal with," says Tawaab. "Making facts about herpes more known, more commonplace, and less of a taboo subject matter can help deter some of the unnecessary aggravations that come with the territory."