How to Tell If the Blister on Your Lip Is a Cold Sore

Blisters that form on the lips can be caused by many things, but the herpes virus is usually the most likely culprit. If you are asking yourself, “To kiss or not to kiss?” when you see the tell-tale crusted scab on your lip, I suggest erring on the side of caution and avoiding kissing, as this virus is very common and contagious. In fact, 20 to 40 percent of adults have the virus that causes herpes labialis, or herpes on the lip.

If you’re concerned about sharing some kisses for Valentine’s Day or another special occasion, take a look at this guide on how to tell if you have a cold sore and what you can do to speed up the healing process.

What Is a Cold Sore?

Cold sores are caused by the herpes simplex virus (HSV). Many people contract the virus during childhood from sharing lip balm or towels or even a loving kiss from a family member. Since the virus lies dormant in the nerve endings, you might not notice any symptoms for many years.

When your immune system is suppressed, by having a cold or due to sun exposure, for example, the virus will rear its ugly head. First, you’ll feel a shooting throbbing pain for a day or two. Then the area will become pink and develop a water-filled blister. You are most contagious during this painful blistering period.

What to Do If You Develop a Blister on Your Lip

The best thing to do if you start to notice these symptoms is to schedule an appointment to see your dermatologist right away. The dermatologist can diagnose HSV by performing what’s called a Tzanck smear, which involves taking a scraping of the blister contents and examining them under a microscope. Because of the way this diagnostic process works, it is best to see your dermatologist as soon as possible so that he or she can see the actual blister.

How to Treat a Cold Sore

After about four to seven days, cold sore blisters will crust into scabs and heal without scarring. In the meantime, there are many different treatment options for HSV. While some people choose to take lysine supplements, which are thought to help shorten the duration of the active virus, there is limited evidence to support this claim and I find these supplements to be minimally effective.

Another option is to try over-the-counter ointments such as Abreva® that contain phenol and menthol to help make the blisters feel better. Unfortunately, these treatments do not really shorten the cycle or decrease shedding of the virus.

On the other hand, prescription topical antiviral ointments such as acyclovir ointment (brand name Zovirax®) and penciclovir cream (brand name Denavir®) can help to shorten the HSV cycle. In my opinion, the best option is an oral antiviral such as Valtrex (valacyclovir) or acyclovir. You should begin taking this medication the minute you feel the burning nerve pain prodrome that signals that the virus is being activated. You can often prevent the blisters from forming if you start the medication in time.

While there is no cure for HSV, people who develop cold sores more than three times a year often take valacyclovir or acyclovir prophylactically to reduce or eliminate breakouts. These medications can be taken long-term without any complications.

You should take valacyclovir prior to dermal filler lip injections, when exposed to extreme temperatures or excessive UV light, when you are ill or have fever, and during stressful times.  The nicknames for HSV are “fever blisters” and “cold sores” because they often occur when you are sick (when the immune system is depressed and HSV can flourish).

Can I Kiss with a Cold Sore?

One of the most common questions that people ask regarding cold sores is whether or not they’re able to kiss while they have a blister on their lip. In short, HSV is contagious and can spread through kissing. Because viral shedding occurs just before the nerve pain and usually ends once the scabs have healed, it is best to be on the safe side and avoid kissing, sharing lip balms, and drinking from the same glass until the blisters and scabs have fully healed. If you have a history of HSV on the lips, it is a good idea not to share lip balm at all.

Other Causes of Lip Blisters

Although HSV is the most common cause, not all blisters on the lips are herpes. Aphthous ulcers, known as recurrent aphthous stomatitis (RAS), can be present on the lips but usually occur on the tongue or inside the mouth. These may start as tiny blisters but become painful ulcers and are recurrent. HSV, on the other hand, tends to show up on the lips or nose area, and the blisters persist for a few days. Other causes of blisters on the lips can be a suction/ friction blisters, sunburn, or a burn from hot food or beverages.

If you have more questions about cold sores that aren’t answered here, feel free to share them in the comments below or post on our Facebook page!


February 28, 2018 Beauty, Skincare