Herpes Simplex Virus
The Herpes simplex virus (HSV) can cause one or more blisters any place on the skin. It is most common around the mouth, lips, and nose or on the genitals and buttocks. There are two types of HSV: most of the time type 1 occurs above the waist (fever blisters, cold sores). Type 2 occurs below the waist. Type 1 is most often acquired in childhood. Type 2 occurs when adults are exposed while having sex with an infected person. The incubation period (time from infection to blisters) ranges from 3 to 20 days. The disease is very common and affects millions of people in the USA. Type 2 infections occur in up to 20% of sexually active adults.
HSV blisters can be primary (meaning the first time the blisters occur) or recurrent (the infection has been present for some time and the blisters may occur from time to time). Only about 10% of people with HSV have symptoms during the primary phase. If symptoms are present during the primary period, they are often more severe than recurrent blisters. Primary symptoms last longer (two or three weeks) and include a fever, mild pain, and swollen lymph glands. Many patients who get recurrent symptoms do not know when they first got the infection.
The disease may remain inactive (latent) for weeks, months, or years before the blisters return. During this time, the HSV hibernates in nerve tissue. When it becomes active, it travels through the nerves and blisters form on the skin supplied by these nerves (see picture below). It is hard to predict when the blisters will recur. It may be weeks, months, or years apart. Some things that may trigger them are being exposed to sunlight, colds or other viral infections, stress, or skin irritation. Some are triggered by a woman’s period. There may be other, unknown factors that bring on eruptions.
Often the doctor can diagnose this disease simply by looking at the blisters. If there are questions, your dermatologist may do a skin scraping and inspect it under a microscope. He or she may also have a culture checked for HSV.
If you have blisters, or if you feel that you are about to have blisters (tingling, burning, or minor pain in the area), do not let that area come in contact with another person. Avoid kissing, sexual intercourse, and oral-genital contact. Do not share eating utensils, washcloths, underwear, or swimsuits. You are most contagious during the first three days of symptoms.
Serious Complications of HSV
The virus can affect the cornea, the clear covering on the front of the eye. Avoid rubbing or touching your eyes if you have an active blister. Corneal infection can cause pain, redness, sensitivity to light, and a discharge of fluid from the eye. If this occurs, you should see an eye doctor (ophthalmologist). Early treatment will prevent scarring of the cornea or other ill effects.
A pregnant woman who has active type 2 HSV blisters when her baby is born can pass the virus on to the baby. This can cause a brain infection in the baby and can result in serious damage or mental retardation. Be sure to tell your OB (obstetric) doctor if you have had problems with recurrent symptoms, if you suspect you have contracted HSV, or if the father of your baby, or another sexual partner has an HSV infection. Sometimes a Cesarean section is advised.
Acyclovir (Zovirax®) and valacyclovir (Valtrex®) are drugs which are used to treat HSV infections. These drugs are most often safe and have very few side effects. The most common side effects are stomach upset and headache. It may be taken with food, but should not be taken with antacids. Probenecid (Benemid®), a gout medicine, prevents the kidneys from clearing acyclovir from the body. If you are taking probenecid or any other medicine, be sure to tell your doctor.
Acyclovir and valacyclovir are used in three ways.
- Oral pills taken for 3 -5 days when the blisters recur.
- A pill taken every day for up to six months to prevent recurrence.
- Intravenously (IV) for severe symptoms. (Acyclovir)
Your dermatologist will recommend what may be best for you.
The safety of acyclovir in pregnancy is unknown. It should only be given if the likely benefits outweigh the risks. It should not be used by nursing mothers. Acyclovir does not cure HSV, but it works well to treat its symptoms during an outbreak.
Who is to Blame?
When one partner in a sexual relationship gets genital herpes, the normal response is to blame the other partner. Because this infection can begin with no symptoms or only slight symptoms, and because it can remain dormant for years, there is no way to tell where, when, or from whom the infection was acquired. If you have a known HSV infection, you should discuss this with all sex partners, abstain from sex when there are active lesions, and always practice safe sex.
UW Dermatology Department
1 S. Park St 7th Floor
Madison, WI 53715
Clinic: 608 287-2450
American Family Children’s Hospital
Pediatric Dermatology Specialty Clinic
1675 Highland Ave.
Madison, WI 53792
Clinic: 608 263-6420
The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Any duplication or distribution of the information contained herein is strictly prohibited.
Last Updated: 02/13/2013
Copyright © 02/13/2013 University of Wisconsin Hospitals and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#6465
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