What causes a cold sore? The reason is not as taboo as some might think.

So, you have a cold sore, otherwise known as oral herpes.

These fluid-filled blisters often found on or around the mouth are not only painful, they may also inflict feelings of shame. “People hear herpes and they immediately think of a highly stigmatized virus,” says Dr. Chris Adigun, a board-certified dermatologist in Chapel Hill, North Carolina.

This stigma has very real consequences. According to a poll by Compeed, a brand that makes treatment options for cold sores, 28 percent of respondents revealed they stayed home because of a cold sore outbreak. People with cold sores sometimes “worry that people will not want intimate or social relationships with them because of it,” adds Adigun. But does the source of cold sores truly warrant this shame?

What causes a cold sore?

A cold sore is “a reactivation of a latent herpes simplex virus infection,” says Adigun.  People who get cold sores were once infected with the herpes simplex virus, also known as herpes. This virus remains dormant in the body for periods of time until it’s reactivated by a trigger. This reactivation of the virus causes an outbreak of cold sores.

There are two types of the herpes simplex virus. Type 1 (HSV-1) is the main cause of cold sores, according to the World Health Organization.

What triggers cold sores?

The Mayo Clinic outlines several common triggers for cold sores:

• A fever or viral infection
• UV exposure
• Stress
• Hormonal changes
• Changes in the immune system
• Injury to the skin

Sometimes people will have triggers that are personal to them, says Adigun. “For example, spicy foods may be a trigger for someone. But more than likely spicy foods may be just for them, whereas we know that a febrile illness, a high-stress situation, UV exposure all those are also triggers for them.” A febrile illness occurs when one’s body temperature is over 99.5 degrees Fahrenheit, according to Study.com.

How did I become infected with the herpes virus?

HSV-1 is spread through the saliva of someone with the virus. Common ways that the virus spreads are through kissing and sharing cups or utensils.

Experts think that most Americans are first exposed to the virus during early childhood, says Adigun. “You have to have exposure to the virus. In the United States, we think this happens in like pre-school or like early in the household,” she says.

You can get the virus from possibly anyone who has been infected. There is increased viral shedding when someone has an active cold sore, says Adigun. But an infected person can spread it to you even if they don’t have an active cold sore or have never had a cold sore before.

This helps make the virus incredibly common. Fifty to 80 percent of adults in America have oral herpes, according to Johns Hopkins Medicine.

Adigun emphasizes this prevalence to anyone who feels shame about their cold sore. “When I see someone for this and …. they think that ‘this is the end of the world’ [or] that they have this badge of shame,” she continues, “I spend a lot of my time counseling people that ‘No this is so incredibly prevalent. You are not the anomaly you are the norm.’”

“This is the American experience,” she adds.

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