Skin Deep

Before kissing your sweetheart, make sure that blister is not herpes

This column has been updated to set the record straight about Abreva, an over-the-counter cold sore medication.

If you notice a blister start to develop on your lip, your first thought might be that it is a cold sore. Since about 20 to 40 percent of adults carry the herpes simplex virus that causes cold sores, these blisters are common and also very contagious. If you think you might have a cold sore, here’s what you need to know.

What causes a cold sore?

Cold sores, also known as herpes labialis, are caused by the herpes simplex virus (HSV). This virus can remain dormant in your body’s nerve endings for years before presenting symptoms, so it can be difficult to pinpoint when you may have contracted it. The most common ways to get HSV are by sharing lip balms, towels, drinking glasses and kissing.

Once you have HSV, you may develop a cold sore blister when your immune system is compromised. This can happen when you’re sick with the cold or flu or when you’ve been out in the sun too long. The first sign of a cold sore is usually a throbbing pain in your lip for about one or two days. Then a painful, fluid-filled blister will develop. HSV is most contagious during this period.

What to do if you have a cold sore

As soon as you notice the first signs of a cold sore, make an appointment with your doctor. If you’re someone who gets cold sores regularly, find a good dermatologist in your area whom you can work with to help limit outbreaks. If this is your first cold sore, your dermatologist can swab a sample of the blister on your lip and test it for HSV. Once you have an accurate diagnosis, you can more effectively treat your symptoms and take steps to stop the virus from spreading.

Here are a few tips for treating a cold sore:

▪ Over-the-counter medications can help to reduce your symptoms, but most won’t do anything to get rid of the virus. “Abreva is actually the only over-the-counter cold sore medication that treats the virus itself and is approved by the FDA to shorten healing time and the duration of symptoms,” according to a spokeswoman in New York.

▪ Talk to your doctor about prescription topical or oral antiviral medications. In my opinion, taking Valtrex, an oral antiviral drug, is the best way to shorten the cycle of the virus and possibly even prevent the blister from forming if taken early enough.

▪ Take Valtrex or another antiviral prescribed by your doctor before getting injectable fillers in the lips, going out in the sun, or when you are under a lot of stress.

▪ Do not kiss or share lip gloss until the blister has completely healed. If you get cold sores regularly, try not to share lip products at all.

Other types of lip blisters

Cold sores aren’t the only type of blisters that can form on the lips, but they are the most common.

Aphthous ulcers can be similar, but they tend to appear on the tongue or inside the mouth instead of directly on the lips. Lip granulomatous can sometimes look like a blister, but this condition is usually associated with swelling of the lips. Blisters on the lips might also be caused by sun exposure, hot food or beverages, or friction or suction.

The only way to know for sure what could be the cause of your blister is to consult a board-certified dermatologist for an accurate diagnosis and treatment options.

Dr. Leslie Baumann is a board-certified dermatologist, New York Times best-selling author and CEO of Baumann Cosmetic & Research Institute in Miami.