What's a Cold Sore, and How Are They Caused?

Anyone who has had a cold sore knows that they're painful and embarrassing—but what exactly are they?

Cold sores are red, fluid-filled blisters that usually form near the mouth and last for about two weeks or longer. Yikes, we know. The kicker is that there's no cure for cold sores and once you have them, they can come back at any time. Thankfully, there are medications used to speed up the recovery process and also prevent them from coming back as explosive.

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What Causes Cold Sores?

Cold sores are caused by the herpes simplex virus. There are two types of the herpes simplex virus, and the simplex type 1 virus (HSV-1) is what usually causes cold sores.

Visible cold sores are contagious, but the virus can also be spread even when blisters aren't present, which is the tricky part. You can get infected by coming into contact with infected individuals with or without cold sores by kissing, sharing cosmetics or sharing food. Believe it or not, about 75-80% of the population has the virus, but for many, it remains dormant in the body. If fact, most people who carry the virus don't even know it because they don't have symptoms at all—nuts, right?

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What to Do If You Feel a Cold Sore Coming On

If you do have cold sores, don't panic. Even though there's no permanent cure, there are options to calm episodes and get them to heal quicker. The most important thing is trying to locate your cold sore triggers. Some people with the virus say they get more frequent outbreaks when their immune systems are weak, during illness or times of stress. Other factors that can increase your risk for a breakout include sun exposure, menstruation, dental work or fever.

Typically, you'll feel a tingling or burning sensation a few days prior. Then, the cold sore will feel swollen and will eventually scab and dry up. Once the scab is fully healed, the physical cold sore is no longer contagious.

If you're concerned that you or someone you know has a cold sore, it's better to err on the side of caution and not share food, drinks, makeup or kiss until it's fully healed.


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