CareNow® - September 11, 2019

Cold sores, also called fever blisters, are small, fluid-filled blisters that appear around the lips and mouth, caused by a herpes simplex virus type 1 (HSV-1).

An estimated 50 to 80 percent of people in the U.S. are living with HSV-1, with most adults being exposed to the virus by the time they’re 50 years of age.

Cold sore blisters will typically break on their own, resulting in a scab that will eventually fall off. This process usually takes about two weeks, which means that cold sores can still be spread even once they’ve scabbed over.

Because HSV-1 is very contagious, it’s important to know how the virus is spread and what you can do to prevent getting it.

What is it like to have a cold sore?

Cold sores can cause pain, a burning sensation or itching in the affected area before they burst and form a scab. These tiny blisters usually develop on the lips or directly around the mouth either by themselves or in a cluster.

Without treatment, a cold sore will typically clear within seven to 10 days; however, the virus is very contagious and can easily spread.

Once you’ve contracted the cold sore virus, it will remain in your body for your entire life. Most of the time it will be inactive with occasional flare-ups, causing a cold sore to appear.

Are cold sores an STD?

Many people worry when they get a cold sore that they’ve contracted an STD, but that isn’t necessarily the case. The most common cold sores are caused by the herpes simplex virus type 1 (HSV-1), which is not a sexually transmitted disease (STD). A similar virus, herpes simplex virus type 2 (HSV-2) causes genital herpes, an STD.

Both HSV-1 and HSV-2 can be transmitted through saliva, body secretions or oral sex. Some people carry a latent form of the virus—only experiencing one cold sore in their lives—but they can still transmit the virus to another person.

What causes cold sores?

The cold sore blisters that appear on the lip are caused by a virus (HSV-1) that enters the body via saliva or body secretions. Often, the virus remains inactive most of the time. When the virus is triggered, a cold sore can develop.

How often the virus is triggered varies from person to person. Some people have only a single outbreak with no recurrence, while others experience at least two to three outbreaks a year. It is also possible for someone to carry the virus for his or her entire life and never experiencing a cold sore in their lives.

How long are cold sores contagious

The HSV-1 virus is extremely contagious—even when you don’t have a cold sore. Many people believe cold sores are no longer contagious once they’ve scabbed over, but this isn’t true. You are most contagious for two weeks after the cold sore initially appears, but because the virus lives in the body forever, it is always transmittable to others.

If you are experiencing a breakout, it is important to avoid close contact with others. If you have the cold sore virus, remember that it is possible to transmit it to others, even when you don’t have a cold sore.

Cold sores vs canker sores

Because they have similar triggers and treatments, cold sores and canker sores are often mistaken for one another.

Canker sores, also referred to as mouth ulcers, are small, painful lesions that develop on the soft tissues of your mouth or at the base of your gums.

Cold sores, on the other hand, are small fluid-filled cold sores that typically appear on the nose, lips or anywhere around the mouth.

Unlike cold sores, the cause of canker sores is unknown. It’s suspected that injury to the mouth, oral hygiene products, food sensitivities, stress, allergic reactions or a diet lacking certain vitamins may contribute to the cause of the sores.

How are cold sores treated?


Unfortunately, once you’ve contracted HSV-1, there is no way to get rid of the virus. But you can do a few things to help you manage the symptoms.

Antiviral medication, either in the pill or cream form, is typically the quickest way to heal a cold sore. Over-the-counter treatments, such as Abreva®, can be effective for cold sores that are not severe. If the infection is a severe one, your provider can prescribe an antiviral medication or give you an injection to alleviate the symptoms.

To keep redness and swelling to a minimum, apply a cold compress (or an ice cube) to the affected area.

How to prevent cold sores

To prevent contracting or spreading HSV-1, there are several things that you can do:

  • Avoid close physical contact—such as kissing—with someone who has a cold sore.
  • Do not share items that have been in contact with another person’s mouth, like eating utensils, straws or cosmetics.
  • If you have a cold sore, don’t touch it (unless you’re applying a topical medication) to prevent the virus from spreading.
  • Because babies and those with weakened immune systems are most vulnerable to infection, avoiding physical contact with them if you have the virus.

Can urgent care treat cold sores?

If you’ve contracted HSV-1 and a cold sore has appeared, it’s a good idea to see a provider who can properly evaluate the sore.

Seek medical attention if you experience any of the following:

  • You have a weakened immune system, which can put you at a higher risk for a complication
  • Your cold sore doesn’t heal within two weeks
  • Your symptoms become severe or frequent
  • You notice irritation spreading to your eyes

For quality medical care available after hours and on the weekend, consider visiting your local CareNow® location.

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Disclaimer: Patients’ health can vary. Always consult with a medical professional before taking medication, making health-related decisions or deciding if medical advice is right for you.