Herpes simplex


ICD-9: 054.x


Cold sores and fever blisters are skin eruptions occurring about the perimeter of the mouth, lips, and nose or on the mucous membranes within the mouth. Sometimes tingling and numbness may precede or follow these eruptions. The condition affects people of any age.


These lesions are produced by the herpes simplex virus type 1 (HSV-1). It is estimated that 9 of 10 persons have been exposed to HSV-1. This virus may lie dormant within the body for extended periods, reactivating during periods of lowered resistance or emotional and physical stress. Cold sores may erupt following a rise in body temperature, such as may occur during a common cold or even preceding menstruation. In some instances, however, they may occur before the onset of illness or for no apparent reason at all.

Signs and Symptoms

The characteristic lesions are small, pale vesicles appearing individually or in clusters, especially on the lips or about the mouth. The lesions may also be seen elsewhere. The affected area may burn and sting. The lesions may eventually break, forming ulcers or crusts. The crust then falls off and the redness goes away. The whole process takes about 10 to 14 days.

Herpes simplex

FIGURE. Herpes simplex. Primary infection in adult seen on a forefinger. (From Reeves, JRT, and Maibach, H: Clinical Dermatology Illustrated: A Regional Approach, ed 3. FA Davis, Philadelphia, 1998, p 64, with permission.)

Diagnostic Procedures

The diagnosis is made on the basis of the individual’s characteristic lesions. The virus may need to be isolated by histologic examination of the scrapings.


Treatment is strictly symptomatic. The drug valacyclovir will shorten the outbreak and lessen recurrence.

The lesions should be kept as dry and clean as possible and protected from trauma. Topical analgesics or ointments containing docosanol or benzalkonium chloride may be applied to relieve burning and itching and increase healing. Antibiotic ointments may be recommended to prevent secondary infection of open lesions.

Complementary Therapy

There may be some relief from the use of L-lysine 500 mg, an amino acid, found in the vitamin section of any drugstore. As soon as clients feel the burning or tingling, they should take 3 or 4 tablets a day for 2 days and then 2 tablets until the blisters dry. (Instruct clients not to take L-lysine on an empty stomach.) Vitamin E oil may dry the sores within 5 to 7 days.


HSV-1 is spread via close contact, such as kissing, or sharing drinking glasses, eating utensils, and lipstick. Even towels should not be shared with someone who has an outbreak. This virus can be spread to the genitals by oral-genital contact. Outbreaks of HSV-1 in the genital area tend to be less severe than those caused by HSV-2, which is a strain of genital herpes. HSV-1 can spread from person to person even when the infected individual has no outbreak.


Cold sores and fever blisters usually resolve within 1 to 3 weeks. The HSV-1 resumes dormancy, however, and may reappear given favorable conditions. Sometimes another infection or exposure to wind or sun can reactivate the virus.


There is no specific prevention other than avoiding intimate contact with persons with visible cold sores.