The Truth About Blisters on the Lips: Are Cold Sores Herpes?

Cold sores are tiny blisters that are most often found on the lips and around the mouth. Sometimes referred to as fever blisters, they can also appear elsewhere on your face – like your nose and cheeks – as well as on your fingers. These blisters typically fall off and heal on their own within seven to ten days.

Although their name may suggest otherwise, cold sores aren’t related to the common cold or fevers. Instead, they are the symptom of another virus that’s affecting about two-thirds of people under the age of 50 around the world.


Herpes is a common name for all changes on the skin caused by the herpes simplex virus. This virus commonly appears in two forms: the herpes simplex virus type 1 (HSV-1) and the herpes simplex virus type 2 (HSV-2).

While HSV-2 typically affects the genital area and is responsible for genital herpes outbreaks, HSV-1 usually affects the skin on the face. One of the most common symptoms of HSV-1 infections are cold sores. Herpes simplex type 1 is also known as oral herpes, seeing as it most often affects the skin around the mouth and the lips. Cold sores may also appear inside the mouth and even inside the nose.


HSV-1, the virus that causes cold sores, is very common. Most people pick it up when they are just a baby. In fact, more than 85% of them contract it from their mothers during delivery. The rest catch it when their eyes or mouth get in direct contact with a cold sore, when they are kissed by an adult with an active cold sore infection, or when someone touches a cold sore right before they touch the baby’s skin.

Whereas HSV-2 is transmitted almost exclusively through sexual contact, HSV-1 doesn’t have to be. Any direct oral-to-oral contact with an infected person or an oral contact with a skin surface with an active cold sore outbreak can be enough to contract HSV-1 as an adult. In rare cases, HSV-1 can also spread to the genital area through oral sex and cause a genital herpes outbreak.

As soon as your skin gets in contact with HSV-1, the virus travels through the skin and enters a group of nerve cells called ganglion that’s located in the autonomic nervous system. The virus will settle there and stay in your body for the rest of your life. It can either remain dormant without causing any symptoms or reactivate periodically to cause recurring cold sore outbreaks.


The development of cold sores starts when the herpes simplex virus type 1 that has been dormant in your body “decides” to reactivate. When that happens, the virus will travel through your nerves until it reaches the location of the original infection (usually the lips).

Once the virus reaches the original infection site, the area just below the surface of your skin will start tingling, burning, or itching. Within a day or two, a red bump will appear on the skin’s surface. Shortly thereafter, this bump will turn into a small, fluid-filled blister, i.e. a cold sore.

Over the next few days, this cold sore will slowly expand until it eventually bursts and dries up. After that, a yellow crust will appear in place of the blister. The crust will fall off and reveal a light-pink skin area that will quickly heal. With the healing process in full swing, the virus will go back to the ganglion where it will stay dormant until the next outbreak.

The entire life cycle of a cold sore – from formation to the start of the healing process – usually lasts no longer than 10 days. Cold sores often accompany other acute health conditions or stressful events that affect your immune system.


Cold sores are highly contagious, especially while you’re experiencing an active outbreak. Any skin-on-skin, oral-on-oral, or oral-on-genital contact with someone who has cold sores is likely to result in an infection. However, because an HSV-1 infection can be asymptomatic in many cases, you may even contract the virus from a person who doesn’t have cold sores or any other visible symptoms.

To avoid contracting HSV-1 or infecting others with it, you need to avoid any direct contact during the outbreak. The virus can easily be transmitted through shared glasses, cups, and utensils, which is why proper kitchen hygiene is of utmost importance. Personal hygiene is just as important, as touching a cold sore and then touching your nose, your mouth, or cuts on your skin can all lead to an infection.

It is particularly important to avoid touching your eyes after you have touched a cold sore. Otherwise, HSV-1 may cause an eye infection, which could lead to serious complications like glaucoma, corneal scarring and – in extreme cases – permanent vision loss.


Cold sores usually clear up on their own within a week or two and don’t require any treatment. Still, if you want to speed up the recovery process and reduce the accompanying pain, you may ask your doctor to prescribe some medication.

Depending on your symptoms, the doctor may recommend one of the following:

  • Over-the-counter or prescription antiviral creams
  • Cold sore patches to be worn over the cold sore until it heals
  • Antiviral tablets and pills for severe infections

Although a treatment isn’t normally required, you should see your doctor if you have another health condition that is negatively affecting your immune system. Furthermore, if the symptoms don’t clear up within 10 days, it is best to consult with your doctor. To ease the healing process, you can use ice packs to cool the affected area of the skin and take over-the-counter pain relievers if necessary.


Because HSV-1 remains in your body even after you recover from a case of oral herpes, you may experience further cold sore outbreaks in the future. Recurring episodes are particularly common within a year of your first outbreak before your body has had a chance to build enough HSV-1 antibodies.

To reduce the risk of cold sore recurrences, you need to work with your doctor to identify the trigger of your previous outbreak and come up with effective ways to avoid it. For example, if the culprit is stress, you should find ways to reduce it. Similarly, if excessive exposure to sunlight seems to trigger outbreaks, you should use a combination of hats, beach umbrellas, sunscreen, and lip balms with SPF while outside.

If you’re having frequent cold sore outbreaks, you should go to your doctor. They might recommend lifestyle and dietary changes to fix the problem and prescribe an antiviral drug to help battle the ongoing oral herpes outbreak.


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