Cold Sores

WHEN TO SEE YOUR DOCTOR

* The first sore or any subsequent sore is accompanied by fever, swollen glands or flu symptoms.

* You get four or more eruptions in a year.

* The pain interferes with eating or daily living.

What Your Symptom Is Telling You

A cold sore sounds so benign, like a little inconvenience you get along with the sniffles. You probably think of it as an innocuous nuisance that won't bother anyone and will go away soon enough.

Well, it'll go away, but it's far from innocuous. What we call cold sores or fever blisters actually are highly infectious mouth sores that affect about one-third of all Americans.

Cold sores are usually caused by the herpes simplex Type I virus, a variant virtually indistinguishable from the herpes simplex Type II strain, which normally affects the genitals, according to Eric Z. Shapira, D.D.S., a trustee on the national board of the Academy of General Dentistry and a dentist in private practice in Half Moon Bay, California. Once you get the virus, you have it for life and any subsequent eruptions will appear in exactly the same spot, he says.

A variety of environmental and physiological factors can coax a cold sore to reappear, including spicy food, sunlight, menstrual cycles, rainy days, stress and a fever.

Cold sore infections are quite common. You get one through contact with people who already have the virus, either by kissing them or touching them where they have an active, open lesion. Some 40 percent of the people with oral sores actually have the strain of the virus that usually affects the genitals, according to JoAnne Allen, D.D.S., a dentist in private practice in Albuquerque. And about 60 percent of the herpes virus found on genitals comes from the Type I strain most commonly found in the mouth.

As opposed to canker sores, which target the fleshy parts on the inside of the mouth, cold sores almost always erupt on or around the lips, says D'Anne Kleinsmith, M.D., a dermatologist in private practice in West Bloomfield, Michigan. Though they appear less frequently on the inside of the mouth, they can hit the parts that don't move—the gums and the roof of the mouth and occasionally the nostrils, fingers and even the eyelids.

The very first time you get a cold sore will probably be the most painful, Dr. Kleinsmith says. You'll also probably run a temperature and feel as though you've come down with the flu. In subsequent eruptions, you'll notice a tender, tingling sensation 36 to 48 hours before the cold sore appears. Usually, several round, reddish, pus-filled sores sprout in a cluster, often eventually forming one big ulceration that burns and swells until it breaks open, forms a yellow crust and fades away—all within a week to ten days—without scarring.

After the first one, subsequent cold sore eruptions inevitably—and unpredictably—occur every few months or so, sometimes at whim, sometimes because of factors like stress, fatigue, illness or cold weather. "There's no way to predict when or how frequently they erupt," Dr. Shapira says. "It depends on the person."

Symptom Relief

When cold sores appear, here's what to do.

Keep it to yourself. The open ulceration is extremely infectious, Dr. Allen cautions. So be careful if you touch it, and don't touch anyone else after you've touched it. That means no kissing and no oral sex until the sore disappears. And no sharing towels, toothbrushes or cups, either.

"Since it can be so easily passed on to other mucous membranes," she says, "don't touch the sore and then rub your eyes or your nose or your genitals. If it gets in your eyes, it could cause blindness." (This is extremely rare but certainly possible.) You also can transfer the virus and the sores anywhere there's an open wound, like a cut on your finger, Dr. Shapira adds.

Wait for the scab. Even after a scab has formed, you can still transfer the virus to someone else or to some other part of your body. "I'd wait a week or two after the scab comes off before you resume kissing or any other contact," Dr. Shapira says.

Ask for acyclovir. Only one prescription drug, acyclovir, is used to treat all strains of herpes, whether on the mouth or the genitals, according to Dr. Shapira. He recommends a two-pronged approach—applying acyclovir ointment topically to the area as soon as you feel a cold sore coming on and taking the pill version orally.

Acyclovir prevents the virus from reproducing, Dr. Shapira says, and it should prevent a sore from forming if you catch it soon enough. If one or two small blisters appear, they'll probably last only a few days, he says. Without the drug, you might have a crusted ulcer that lasts two weeks. The pain, at least, usually will subside in 24 hours, he says.

Anesthetic might ease the pain. Over-the-counter ointments containing benzocaine can be applied directly to the herpes sore to numb it enough so you can eat comfortably, Dr. Allen says, but they won't speed healing.

Dull your diet. Spicy or acidic foods will aggravate the sore and produce a lot of pain, Dr. Shapira says. So take it easy on the tomatoes, jalapeño peppers and orange juice.

See also Canker Sores