Herpes genital (genital Herpes simplex)

Alternative names
Genital herpes; Herpes simplex - genital; Herpesvirus 2; HSV-2

Genital herpes is a sexually transmitted viral infection that is characterized by repeated eruptions of small, painful blisters on the genitals, around the rectum, or covering adjacent areas of skin.

Causes, incidence, and risk factors

Herpes is caused by two viruses - herpes simplex virus type 1 (HSV-1), and herpes simplex virus type 2 (HSV-2). While statistics vary, research shows that 90% of the population has been exposed to HSV-1, “oral herpes,” and 25% of the population aged 25-45 years old in the United States has been exposed to infection with HSV-2, “genital herpes.”

HSV-1, the virus responsible for common cold sores, can be transmitted through oral secretions. This is either during kissing, or by eating and drinking from contaminated utensils.

Additionally, HSV-1 can cause genital herpes through transmission during oral-genital sex, thus both strains of the virus may be transmitted by sexual contact. Initial oral herpes infection, however, usually occurs in childhood. It is therefore not classified as a sexually transmitted disease.

HSV-1 is responsible for only 5-10% of genital herpes cases, while HSV-2 causes the majority of genital herpes cases. HSV-2 can be transmitted through oral or genital secretions. An estimated 86 million people worldwide are thought to have genital herpes.

Because the virus is transmitted through secretions from the oral or genital mucosa, common sites of infection in men include the shaft and head of the penis, the scrotum, inner thighs, and anus. The labia, vagina, cervix, anus, and inner thighs are common sites in women. The mouth can also be a site of infection in both sexes.

Research suggests that the virus can be transmitted even in the absence of clinical disease, so that a sexual partner without obvious genital herpes sores may still transmit the illness. In fact, asymptomatic spread may actually contribute more to the spread of genital herpes than do active sores.

Various complications are associated with herpes infection. The herpes virus is of special significance to women. It has been implicated in causing cancer of the cervix. The risk increases when HSV is present in combination with human papilloma virus (HPV), the virus responsible for genital warts (condyloma).

For pregnant women, the presence of either HSV-1 or HSV-2 on the external genitalia or in the birth canal is a threat to the infant. Subsequent infection of the newborn can lead to herpetic meningitis, herpetic viremia, chronic skin infection, and even death.

Herpes infection also poses a serious problem for the immunocompromised individual (patients with AIDS, undergoing chemotherapy or radiation therapy, or taking high doses of cortisone preparation). These people may suffer infections of various organs including:

  • Herpetic keratitis - herpes infection of the eye leading to scaring within the cornea and eventual blindness.  
  • Persistent infection of the mucous membranes and skin of the nose, mouth, and throat.  
  • Herpetic esophagitis - infection of the esophagus.  
  • Herpetic hepatitis - infection of the liver causing inflammation of the liver and eventual liver failure.  
  • Encephalitis - a very serious infection of the brain. If untreated, approximately 60-80% of those who contract this condition will progress to coma and death within a few days. Those who recover often suffer some impairment, ranging from mild neurological impairment to paralysis.  
  • Pneumonitis - infection of the lung causing a life-threatening pneumonia.


For people with no prior contact with HSV-1 or 2, initial infection is characterized both by systemic (whole body) as well as by local symptoms and signs. Generalized symptoms include: fever, malaise, muscle aches, and decreased appetite. Local symptoms are described below.

Prior to the appearance of blisters, the infected individual may experience increased skin sensitivity, tingling, burning, itching, or pain at the site where the blisters will appear.

The skin may redden, and then erupt with multiple small blisters (vesicles) filled with clear, straw-colored fluid. The blisters then break, resulting in shallow ulcers that are very painful. These ulcers eventually crust over and slowly heal over a period of 7 to 14 days.

The outbreak may be accompanied by enlargement and tenderness of lymph nodes in the groin. Women also may develop vaginal discharge and painful urination. Men develop painful urination if the lesion is near the opening of the urethra.

Once a person is infected, the virus hides within nerve cells, making it difficult for the immune system to detect and destroy it. Within the nerve cells, the virus may remain dormant for an extended time, a period called “latency.”

The infection may reactivate at any time, at which point the individual once again develops painful blistering over the genitals, anus, inner thigh, or mouth. A variety of events may trigger latent infection to become active, including mechanical irritation, stress, menstruation, and fatigue.

Recurrent attacks can occur as seldom as once per year, or so frequently that the symptoms seem continuous. Recurrent infections in men are generally milder and of shorter duration than those experienced by women.

Signs and tests

  • Viral culture of blister fluid from lesion positive for herpes simplex virus. Herpes simplex virus may grow within 2-3 days. If this test is positive, it is almost 100% accurate, especially if the fluid is from an initial blister rather than a recurrent blister. Since viruses can be hard to grow, it is often negative, even when herpes is present.  
  • Detection of the herpes simplex virus DNA by PCR from the blister fluid. The blister fluid contains human cells and virus particles. PCR is a technique that detects small amounts of DNA and could tell you if the herpes virus was present in the blister.  
  • Tzanck test of skin lesion may show results consistent with herpes virus infection. This test involves staining human cells within the blister fluid with a dye. If the cells from the fluid contain viral particles, they become visible. However, the test cannot determine which strain of virus is present in the blister.


Genital herpes cannot be cured. However, treatment can relieve the symptoms. Medication can rapidly decrease the pain and discomfort associated with an outbreak and can shorten healing time as well.

Four oral agents are currently being prescribed, including acyclovir (Zovirax), famciclovir (Famvir), penciclovir (Denavir), and valacyclovir (Valtrex).

These medications have been shown to speed the healing and resolution of symptoms in first attacks more than in recurrent episodes of genital HSV-1 and HSV-2 infections. These medications do not cure the herpes infection. Instead, they suppress the symptoms.

If necessary, daily suppressive therapy can be used, and has been shown to reduce the frequency of recurrence among patients with frequent genital herpes outbreaks.

For maximum benefit during recurrences, therapy should be started as soon as the tingling, burning, or itching starts, or as soon as the blisters are noticed. Possible side effects from these medications include: nausea and vomiting, rash, headache, fatigue, tremor, and very rarely, seizures.

Intravenous acyclovir is sometimes needed for severe herpes infections that can involve the brain, eyes, and lungs. These complications typically develop in immunocompromised individuals.

Foscarnet (Foscavir), a powerful anti-viral agent, is the first choice for treatment of herpes strains that have become resistant to acyclovir and similar drugs. Administered intravenously, the drug can have several toxic effects, such as reversible impairment of kidney function or induction of seizures.

Given these serious side effects, foscarnet is saved only for severe and resistant herpes infections. As with other antiviral drugs, this medication does not cure herpes.

Warm baths may relieve the pain associated with genital lesions. Gentle cleansing with soap and water is recommended. If secondary infection of the skin lesions by bacteria occur, a topical or oral antibiotic can be used.

Support Groups

Joining a support group in which members share common experiences and problems can help the stress associated with this illness. See herpes genital - support group.

Expectations (prognosis)

Once infected, the virus stays in the body for the rest of the individual’s life. Some never have another episode, and some have frequent recurrences. In most recurrences, no obvious trigger is identified. Many people, however, find that attacks of genital herpes occur in conjunction with the following conditions:

  • general illness (from mild illnesses to serious conditions, such as operations, heart attacks, pneumonia and so on)  
  • fatigue  
  • physical or emotional stress  
  • immunosuppression, due to AIDS or such medication as chemotherapy or steroids  
  • trauma to the affected area, including sexual activity  
  • menstruation

In individuals with normal immune systems, genital herpes remains a localized and bothersome infection, but seldom a life-threatening infection.


  • recurrent disease (common)  
  • encephalitis (rare)  
  • spread of the virus to other organs of the body in immunosuppressed people  
  • transverse myelopathy (damage that extends across the spinal cord)  
  • incontinence

Calling your health care provider
Call for an appointment with your health care provider if you have any symptoms suggestive of genital herpes, or if fever, headache, vomiting, or widespread symptoms develop during (or after) an outbreak of herpes.


Condoms remain the best protection against acquiring genital herpes when sexually active. CORRECT and CONSISTENT use of a condom will help prevent the transmission of the disease.

The use of LATEX condoms is mandatory - animal membrane condoms should be avoided, since the virus can penetrate them. The female condom has been tested and shown to successfully reduce transmission risk as well.

Otherwise, prevention is difficult, due to the fact that the virus can be spread to others even when the infected person has no obvious evidence of infection. Clearly, individuals with genital herpes should avoid sexual contact when active lesions are present.

In addition, individuals with known genital herpes, but without current clinical symptoms should inform their partner that they have the disease. This precaution allows both parties to use barrier protection (to prevent the spread of the illness).

Pregnant women with the herpes simplex infection should receive weekly viral cultures of the cervix and external genitalia as the delivery date approaches. If the viral culture is positive for herpes, or active lesions are present at delivery, a cesarean delivery (C-section) is recommended to avoid infecting the newborn.


Q: How is genital herpes transmitted?

A: Herpes simplex virus (HSV) is transmitted from one person to another by skin-to-skin contact. The virus is shed from visible sores, blisters, or a rash during outbreaks, but can also be shed from the affected area between outbreaks of symptoms.

HSV is transmitted to the area of skin with which it comes into contact. There are also some cases by which other types of contact can spread HSV. For example, a variant of herpes, known as herpes gladiatorium, may be passed on during body contact sports, such as wrestling.

Q: Is there a vaccination?

A: Vaccines against herpes have been produced but are still considered experimental drugs. Trials for these vaccines are designed to establish whether the vaccines will prevent outbreaks of genital herpes in people who have not experienced it previously. Conclusive results from trials are not yet available. Vaccines are not, however, a curative or palliative treatment for individuals with herpes.

Johns Hopkins patient information

Last revised: December 3, 2012
by Levon Ter-Markosyan, D.M.D.

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