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Genital Herpes


Kenneth M. Kaye

, MD, Harvard Medical School

Last full review/revision Oct 2019| Content last modified Oct 2019

Genital herpes is a sexually transmitted disease caused by human herpesvirus 1 or 2. It causes ulcerative genital lesions. Diagnosis is clinical with laboratory confirmation by culture, polymerase chain reaction, or serologic testing. Treatment is with antiviral drugs.

Genital herpes is the most common ulcerative sexually transmitted disease in developed countries. It is caused by human herpesviruses 1 (HSV-1) or 2 (HSV-2), which are two of the eight types of herpesviruses that infect humans. (See Overview of Herpesvirus Infections.)

After the initial infection, HSV remains dormant in nerve ganglia, from which it can periodically emerge. When the virus emerges, it may or may not cause symptoms (ie, genital lesions). Transmission may occur through contact with the lesions or, more often, via skin-to-skin contact with sex partners when lesions are not apparent (called asymptomatic shedding).

Pregnant women with genital herpes can transmit HSV (usually HSV-2) to the fetus or neonate. Typically, HSV is transmitted during delivery via contact with vaginal secretions containing HSV. The virus is rarely transmitted transplacentally. Mothers with primary (newly acquired) HSV genital infection have a higher risk of transmitting HSV to the neonate. Most women who transmit HSV to neonates do not have symptoms of HSV infection at the time of delivery. Neonatal HSV infection is a serious, potentially fatal infection.

Symptoms and Signs of Genital Herpes

Most cases of primary genital herpes do not cause noticeable symptoms; many people infected with HSV-2 do not know that they have genital herpes.

Primary genital lesions develop 4 to 7 days after contact. The vesicles usually erode to form ulcers that may coalesce. Lesions may occur in the following locations:

  • On the prepuce, glans penis, and penile shaft in men
  • On the labia, clitoris, perineum, vagina, and cervix in women
  • Around the anus and in the rectum in men or women who engage in receptive rectal intercourse
Images of Genital Herpes

Urinary hesitancy, dysuria, urinary retention, constipation, or severe sacral neuralgia may occur.

Scarring may follow healing. The lesions recur in 80% of patients with HSV-2 and in 50% of those with HSV-1.

Primary genital lesions are usually more painful, prolonged, and widespread and are more likely to be bilateral and involve regional adenopathy and constitutional symptoms than recurrent genital lesions. Recurrent lesions tend to be milder and associated with fewer symptoms.

Diagnosis of Genital Herpes

  • Clinical evaluation
  • Culture and polymerase chain reaction (PCR)
  • Serologic testing

Diagnosis of genital herpes is often clinical based on characteristic lesions; clusters of vesicles or ulcers on an erythematous base are unusual in genital ulcers other than those due to HSV. However, these lesions are absent in many patients.

Tests for HSV should be done to confirm the diagnosis if it is not clear.

Testing is usually done using a sample of fluid from the base of a vesicle or of a newly ulcerated lesion, if present. Absence of HSV in culture, especially in patients without active lesions, does not rule out HSV infection because viral shedding is intermittent. Also, culture has limited sensitivity; PCR is more sensitive and is being used increasingly.

Direct immunofluorescence with fluorescein-labeled monoclonal antibodies is sometimes available; it is specific but not sensitive.

Serologic tests can accurately detect HSV-1 and HSV-2 antibodies, which develop during the first several weeks after infection and then persist. Thus, if genital herpes is thought to be recently acquired, tests may have be repeated to allow time for seroconversion.

HSV serologic testing should be considered for the following;

  • To evaluate patients who have no suspicious genital lesions but who require or request evaluation (eg, because of past genital lesions or high-risk behaviors)
  • To help determine risk of developing lesions
  • To identify pregnant women who do not have genital lesions but are at risk of transmitting herpes to the neonate during delivery
  • To determine whether a person is susceptible to infection from a sex partner with genital herpes

Treatment of Genital Herpes

Genital herpes is treated with antiviral drugs.

Primary eruptions can be treated with one of the following:

  • Acyclovir 400 mg orally 3 times a day  for 7 to 10 days
  • Valacyclovir 1 g orally every 12 hours for 7 to 10 days
  • Famciclovir 250 mg orally 3 times a day  for 7 to 10 days

These drugs reduce viral shedding and symptoms in severe primary infections. However, even early treatment of primary infections does not prevent recurrences.

In recurrent eruptions, symptom duration and severity can be reduced marginally by antiviral treatment, particularly during the prodromal phase. Recurrent eruptions can be treated with one of the following:

  • Acyclovir 400 mg orally 3 times a day for 5 days
  • Valacyclovir 500 mg orally every 12 hours for 3 days
  • Famciclovir 1000 mg orally every 12 hours for 1 day

For frequent eruptions (eg, > 6 eruptions a year), suppressive antiviral therapy with one of the following may be used:

  • Acyclovir 400 mg orally every 12 hours
  • Valacyclovir 500 to 1000 mg orally once a day
  • Famciclovir 250 mg orally every 12 hours

Doses should be adjusted for renal insufficiency. Adverse effects are infrequent with oral administration but may include nausea, vomiting, diarrhea, headache, and rash.

Topical antiviral drugs have only little value, and their use is discouraged.

Evaluation of sex partners of patients with genital herpes is important.

Prevention of Genital Herpes

The best ways to avoid genital herpes are

  • Abstaining from sexual contact (vaginal, anal, and oral sex)
  • Being in a long-term mutually monogamous relationship with a partner who has been tested and is not infected

Risk of genital herpes can by reduced by

  • Using latex condoms correctly and consistently

However, condoms do not cover all areas that can be affected and thus do not fully protect against genital herpes.

Patients with genital herpes should abstain from sexual activity when they have lesions or other herpes symptoms. Patients should be reminded that they can transmit the infection even when they do not have any symptoms.

Preventing neonatal HSV infection

Efforts to prevent neonatal transmission have not been very effective. Universal screening has not been recommended or shown to be effective.

Clinicians should ask all pregnant women whether they have had genital herpes and should emphasize the importance of not contracting herpes during pregnancy.

If women have herpes symptoms (eg, active genital lesions) when labor begins, cesarean delivery is recommended to prevent transmission to the neonate. Pregnant women with genital herpes can be given acyclovir starting at 36 weeks gestation to reduce the risk of a recurrence and thus the need for cesarean delivery.

Fetal scalp monitors should not be used during labor on infants whose mothers have suspected active genital herpes.

Key Points

  • After the initial infection, HSV remains dormant in nerve ganglia, from which it can periodically emerge.
  • Transmission may occur through contact with the lesions, but viral shedding and transmission can also occur when lesions are not apparent (asymptomatic shedding).
  • Most initial infections do not cause symptoms, but primary genital lesions are usually more painful, prolonged, and widespread than recurrent genital lesions.
  • Diagnose based on characteristic genital lesions in patients with lesions and confirm by culture, PCR, and/or serologic tests for HSV.
  • Primary and recurrent eruptions can be treated with acyclovir, valacyclovir, or famciclovir.
  • If pregnant women have genital herpes, consider giving acyclovir starting at 36 weeks gestation to reduce the risk of a recurrence and transmission to the neonate during delivery.

More Information

  • American Sexual Health Association

Drugs Mentioned In This Article

Drug Name Select Trade
valacyclovir VALTREX
famciclovir FAMVIR
Acyclovir ZOVIRAX

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