A healthy living blog from Marshfield Clinic

Cold sores: Common, crusty, contagious

What are cold sores and how can you prevent them

Cold sores are more common and contagious than you think. Learn more about how you can prevent ‘fever blisters.’

You know it’s coming as soon as you feel the tingle in your lip – the dreaded cold sore.

You hope this painful sore will go away lickety-split but it will generally take about seven to 10 days before your lip is back to normal.

Cold sore sufferers know these sores, also called “fever blisters,” are not usually serious but seem to come at bad times and take too long to heal.

Brittany Hughes, a family nurse practitioner at Marshfield Clinic Health System, sees patients in her practice who suffer from these sores caused by the herpes simplex virus (HSV). Two virus types cause cold sores, HSV type 1 and HSV type 2. HSV type 1 usually causes cold sores. Both types can cause sores on the genitals, spread by oral sex. Genital herpes usually is caused by HSV type 2.

“We see patients with cold sores a fair amount,” Hughes said. “Typically it’s not the primary reason we see them but patients do want to talk about them.”

According to Hughes, cold sores are common. More than 50 percent of adults in the U.S. have the virus that may cause cold sores, she said. After cold sore blisters break, fluid forms a crust over the sores and once healed, there are no scars since new skin has formed.

Cold sores are contagious

The contagious virus is spread through close contact from person to person, like kissing, even if you can’t see the sores yet, Hughes said. However, they are much more contagious when the sore is present. It can spread to other people until blisters crust over completely. They most typically appear on the outside of your lips and mouth but can form on the nose or face.

They can be triggered by sickness, stress, hormonal changes, a compromised immune system, sun exposure and even heavy winds. Though cold sore sufferers can have them just about any time, colder temperatures seem to bring them on a little more frequently.

There is no cure and sores can return. There is no way to prevent them other than trying to avoid triggers as much as possible.

As soon as you feel the tingle, consider using antiviral medications available over-the-counter or by prescription from your provider, like valacyclovir and acyclovir, to reduce symptoms, lessen pain and help speed healing. Some people use antivirals regularly to suppress cold sores from developing, Hughes said. Also, applying a cold washcloth to the sore may help soothe symptoms and reduce inflammation.

Prevention is key

Prevention is key from spreading the virus. For example, Hughes said, don’t share anything with someone when you have an active cold sore, like lip balm, a drinking glass or silverware, utensils or towels.

“If you have a sore or feel one coming, don’t kiss babies,” she said. “The virus can be deadly for newborns and cause encephalitis, fevers and other illnesses.”

For people who have a compromised immune system or HIV, the virus also could be very harmful.

There is no connection between colds and cold sores, though.

“You can be more susceptible to the herpes virus when you’re ill with the common cold so you could have them when you’re sick,” Hughes said.

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