What Is a Cold Sore?

Are cold sores an STD? How can you tell if you have one? And how can cold sores be best treated and prevented?

Sanaz Majd, MD
4-minute read
Episode #232

“What is that THING on your lips?”

“Is that some type of  STI (Sexually Transmitted Infection)?”

“Is it contagious?”

These questions are every cold-sore sufferer’s nightmare. It can be embarrassing to display a large red ugly blister anywhere on the face, let alone the lips, which is a conspicuous location. But let me be the first to tell you: cold sores are super common and span all age groups.

What are cold sores anyway? How can we make them disappear as quickly as possible, and prevent future outbreaks? Let’s dispel some myths and reveal the truth about cold sores in today’s episode.

What Are Cold Sores?

Cold sores are caused by a form of the Herpes Simplex virus, a cousin to the chicken pox and shingles viruses.

There are two types of Herpes Simplex Viruses (HSV):

HSV Type I: Affects the lips, mouth, and throat. It is often first transmitted in childhood, believe it or not. This happens if there’s contact with the saliva of someone else that is affected, via shared cups, utensils, toothbrushes, or kissing. It is not an STI typically, and is very common ... even in children.                                                                                                                      

HSV Type II: Is often sexually transmitted and therefore considered an STI. It happens via skin-to-skin contact, and can still be transmitted even without a visible blister. A condom is the only way to prevent its transmission but it can still be transmitted via nearby exposed skin areas; this is a term called “shedding.” If you are diagnosed with genital herpes, it's important to also ask your doctor to test you for other sexually transmitted infections.

It’s important to note, however, that there is some cross-reactivity between the two types, which means that people can also get Type I in the genitals and Type II in the mouth. The most common way cross reactivity happens is while engaging in oral sex.

The First Outbreak:

Breakouts are usually recurrent. But the very first breakout is often the most severe. The virus enters the surface of the skin, lips, mouth, or genitals. Then penetrates deeper through the skin layers and finally to the nerves.  Typically multiple painful blisters can form on the lips, mouth, or throat during the first outbreak. And fever, body aches, and enlarged lymph nodes in the neck are also common with the first outbreak. Symptoms can last up to two weeks.

Further Breakouts

After the initial infection, the virus remains dormant in your body and resurfaces in times of stress or when your immune system is down (like when you are sick). Future outbreaks are not as severe, thankfully, and often last only up to one week. Fever and other symptoms are also rare with subsequent breakouts. Nevertheless, recurrent herpes can be quite a nuisance.


Medical Disclaimer
Please note that all content here is strictly for informational purposes only. This content does not substitute any medical advice, and does not replace any medical judgment or reasoning by your own personal health provider. Please always seek a licensed physician in your area regarding all health related questions and issues.

About the Author

Sanaz Majd, MD

Dr. Sanaz Majd is a board-certified Family Medicine physician who graduated from Drexel University College of Medicine in Philadelphia. Her special interests are women's health and patient education. 

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