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Herpes Simplex (cold sores)

Herpes simplex is a viral infection that attacks the skin and nervous system, and usually produces small, irritating and sometimes painful fluid-filled blisters. These lesions are usually on or around the mouth, lips, nose, (called “orolabial” or “orofacial”) but can appear on the genitals or finger(s). Orofacial HSV infections affect about 15-30% of the population. On average, outbreaks occur three to four times a year. Human exposure to HSV-1 is universal, yet many people never develop lesions.

Herpes simplex is caused by a herpes virus, herpes simplex; usually type 1, herpes labialis (HSV 1). HSV-1 also causes 15-25% of symptomatic genital herpes infections.

After the initial outbreak, the virus usually lies dormant in the nerve ganglia (clusters of tissue). In 20-25% of infected persons, the virus also lies dormant in epidermal (skin) cells. Reactivation may be triggered by sunlight, fever, physical or emotional stress, hormonal changes such as pregnancy or menstruation, or certain foods and drugs Sometimes the trigger is not identified. Infections in epidermal cells seem to reactivate more quickly (within 24 hours) after exposure to triggers than do those in the nerve ganglia (3-5 days).

Image depicting location of cold sore eruption on human face.

Between cold sore eruptions, the herpes simplex 1 virus lies dormant, presumably in the skin or in nearby nerve tissue.

The first symptoms of an orofacial herpes simplex infection usually include; burning, tingling or itching sensations around the edges of the lips or nose; this is the prodrome. Within a few hours, small reddened areas develop followed by the formation of small blisters filled with fluid. Several small blisters may merge to form a larger one. As the blisters enlarge, they rupture and leak sticky golden fluid, which forms crusts. In uncomplicated cases, the herpes outbreak usually runs its course in three weeks or less, and seldom leaves a scar. Occasionally, “shingles” caused by herpes zoster, the chicken pox virus, causes facial lesions. If you have never had a cold sore before, or the lesions are in a new location, you should see a provider to obtain a diagnosis of herpes simplex vs. herpes zoster. This is particularly important if the sores are near the eye, as herpes zoster can cause inflammation of the cornea.

In both the initial and subsequent outbreaks, the blisters and ulcers of herpes simplex are filled with virus and are highly contagious until they heal. Touching a cold sore and then touching other places on your body, or another person, can cause the virus to spread. Viral shedding can occur even in the absence of lesions. To prevent spreading the virus, a person with an orofacial lesion should wash their hands frequently especially after contact with the sore, and avoid kissing and oral sex during outbreaks. To avoid spreading the virus, a person with a history of orofacial HSV-1 should avoid kissing babies and young children, or abstain from unprotected oral sex.

Herpes simplex infection of the mouth is very common; and though the appearance may cause concern, it presents no serious risks to your general health. The main danger involved is spreading the infection to the eye by touching the sore and then touching the eye. This can cause an eye infection or ulceration of the cornea. In very rare cases, herpes virus can infect the brain and other parts of the central nervous system, producing meningitis and encephalitis. This, however, is usually seen only in adults with an immune deficiency disorder or in young children. There is some evidence that herpes virus may help protect the host against some types of cancer. Research is ongoing.

There is no cure for herpes simplex. Most mild cold sores clear up on their own and require no treatment. Over-the-counter cold sore medications can sometimes help reduce the irritation while the sore heals.

Also, your provider may recommend a drying agent to help oozing sore, or antiviral cream. If your recurrences are frequent and severe, your provider may prescribe oral antiviral medication, e.g. acyclovir, which has been shown to decrease the size and severity of herpes outbreaks. These medications have no effect on host cells.

Like all members of the herpes virus family, including chicken pox and mono, the herpes simplex virus stays with us for life. Although you may not always be able to prevent outbreaks, there are some self-help measures that may reduce the frequency of recurrences. When in the sunlight, use a sunscreen with a minimum protection factor of 15 or a preparation containing benzoic acid. Practice stress management techniques such as inhalation exercises or progressive relaxation. Exercise regularly and get adequate rest.

Notify your health care provider if you develop:

Drug Facts & Comparisons. (1996). Antiviral Agent. - page 572
Color Atlas & Synopsis of Clinical Dermatology (1992). - page 70
Clinical Guidelines in Family Practice (1998). pp. 294-295
Burkhart, C. 2006 The Clinical Advisor. A guide to recognizing and treating herpes. November 2006. pp. 26-36
American Social Health Association Web site, search for herpes simplex

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If you are concerned about any difference in your treatment plan and the information in this handout,

you are advised to contact your health care provider.


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