Genital Herpes (HSV-2): Everything You Need to Know

Herpes simplex virus type 2 (HSV-2) is the virus most commonly linked to genital herpes, a sexually transmitted infection (STI) that causes painful blisters and ulcers on the penis, vagina, or rectum. The virus is passed during intimate sexual contact prior to and following the outbreak of ulcers.

Herpes simplex type 1 (HSV-1) is a related virus more commonly linked to oral herpes (a.k.a. cold sores). Even so, HSV-1 can sometimes be passed to the genitals during oral sex.

Person seeks medical care for genital herpes

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Although HSV-2 accounts for most genital herpes outbreaks, it is impossible to tell which virus caused the infection without lab tests.

This article looks at the causes and symptoms of genital herpes and explains how this common viral disease is diagnosed and treated. It also offers tips on when to seek treatment to potentially reduce the duration and severity of an outbreak.

HSV-2 Causes

Genital herpes, also known as herpes genitalis, is one of the most common STIs in the world. It is caused by HSV-2 and, increasingly, by HSV-1.

According to the Centers for Disease Control and Prevention (CDC), around 12% of people in the United States between the ages of 14 and 49 have HSV-2. In 2021, an estimated 572,000 people nationwide were newly infected.

Sex is the predominant mode of transmission. Generally, you can only get HSV-2 when there is genital-to-genital contact with someone who has a genital HSV-2 infection. However, receiving oral sex from someone with an oral HSV-1 infection can also lead to genital herpes.

Once you've been infected with HSV-2, it does not go away. Instead, the virus remains in the body in a latent (dormant) state, embedded in nerve cells near the spine. Triggers like stress, illness, or hormonal changes can cause the virus to reactivate and travel along the nerve route to the site of the original infection, causing a repeated outbreak (recurrence).

Asymptomatic Infection

Not everyone who gets HSV-2 will develop genital herpes. Some people will remain asymptomatic (symptom-free) but still be able to pass the virus to others without knowing it.

While exposure to herpes sores can easily transmit the virus, HSV-2 infections most often occur when you have sex with someone who is either asymptomatic or has mild symptoms that are not readily recognized as herpes. In cases like these, there will be periods during which the virus can be "shed" through the skin of the genitals or rectum.

Some studies suggest that asymptomatic HSV-2 shedding can occur as much as 10% of days.

Risk Factors for HSV-2

Certain risk factors can increase the likelihood of genital herpes, including:

  • Having vaginal, anal, or oral sex without condoms or dental dam)
  • Having multiple and/or anonymous sex partners
  • The presence or history of another STI
  • Being female (which nearly doubles the risk compared to being male)

Black people are diagnosed with genital herpes 4 times more often than White people.

HSV-2 Symptoms

Not everyone with HSV-2 has symptoms or is even aware that they've been infected. Research suggests that around 87% of people with HSV-2 under the age of 50 have never been diagnosed. Most are either asymptomatic or have very mild symptoms that are easily mistaken for other skin conditions.

When symptoms do occur, they usually involve the spontaneous appearance of tiny blisters around the genitals or rectum. Soon after, the blisters will rupture, leaving painful ulcers that ooze, crust over, and eventually heal within two to four weeks.

Symptoms of genital HSV-2 infections can develop within two to 12 days of exposure.

First and Subsequent Episodes

The first genital herpes outbreak will generally be worse than the ones that follow. During a first outbreak, the appearance of lesions will often be accompanied by:

Subsequent attacks tend to be shorter and less severe. They are often preceded by genital pain or shooting pain in the legs, hip, or buttocks several hours or days before the attack.

Over time, the number of outbreaks tends to decrease and become less severe.

Complications

For most people with genital herpes, symptoms can be aggravating but not life-threatening.

However, for people who are severely immunocompromised, such as those with advanced human immunodeficiency virus (HIV), HSV-2 can cause rare but serious complications like aseptic meningitis (inflammation of the lining of the brain).

On the flip side, having HSV-2 increases the risk of getting HIV by around 300%. This is not only because HIV has easier access into the body through open sores but also because HSV-2 increases the number of immune cells, called CD4 T cells, that HIV targets for infection.

Genital herpes can also be passed to an unborn baby during pregnancy, leading to a potentially life-threatening condition known as neonatal herpes. If transmission occurs, the virus can reactivate soon after birth and spread to the baby's lungs, liver, brain, or circulatory system, causing severe illness and even death.

What Does Genital Herpes Look Like?

Genital herpes symptoms can differ from one person to the next, causing a massive outbreak in some people and an uncomfortable rash or redness that can easily be mistaken for other conditions.

When an outbreak is about to occur, people will often experience prodromal (precursor) symptoms such as tingling, itching, or burning around the area where the sores are about to appear.

Soon after, a cluster of itchy or painful blisters filled with fluid will appear on the vagina, vulva, cervix, penis, scrotum, buttocks, anus, or upper thighs. The blisters can vary both in size and density. As the blisters begin to rupture, they turn into open sores that can bleed or ooze a whitish fluid.

Over a period of several days, the sores will begin to crust over and heal. Most outbreaks clear within two to four weeks, usually without leaving any scars.

When to See a Healthcare Provider

The early recognition of genital herpes, ideally during the prodromal stage, allows you to access treatments that can shorten the duration and severity of an outbreak.

Clearly, this can be difficult during your first outbreak, given that you probably won't be expecting it. But, over time, you will be better able to recognize the tell-tale signs and know when it's time to act.

When to Start Treatment

The traditional rule of thumb is that the treatment of genital herpes—in the form of oral antiviral drugs—should begin within 72 hours of the first appearance of lesions.

Getting treated also reduces the risk of infecting others by slowing the rate of viral shedding.

HSV-2 Diagnosis

Genital herpes is often diagnosed with a physical exam and a swab of cells from a herpes sore. The swab can be used for one or several different tests, including:

  • Light microscopy: Used to visualize the cells under a microscope
  • Viral culture: Used to culture (grow) the virus in the lab
  • Nucleic acid amplification test (NAAT): Used to detect HSV based on its genetic material and to help differentiate between HSV-1 and HSV-2

There also are blood tests that can diagnose HSV based on proteins called immunoglobulins (antibodies) produced by the immune system in response to the virus.

The two categories of antibody tests used to detect HSV are:

  • Immunoglobulin M (IgM) tests: Used to detect an antibody produced soon after infection, which may help diagnose early infection
  • Immunoglobulin (IgG) tests: Used to detect a longer-lasting antibody, which can help differentiate between a recent infection and a recurrence

Certain IgG blood tests can also tell you whether you have HSV-1 or HSV-2.

CDC Screening Recommendations

The CDC does not recommend herpes testing for people without symptoms as it is unlikely to change risk behaviors or slow the spread of the virus. HSV blood testing may be useful if:

  • You have symptoms of genital herpes.
  • You are having (or have had) sex with someone with genital herpes.
  • You want a complete STI exam, especially if you have multiple partners.

Treatment

There is no cure for HSV-2. However, antiviral drugs can reduce the duration and severity of an outbreak. They can also reduce the risk of outbreaks in people with recurrence and reduce the risk of passing the virus to others.

The treatment varies based on whether this is your first or subsequent outbreak.

First Outbreak

Everyone who gets a first herpes outbreak should be treated. While many experts recommend initiating treatment within 72 hours of the appearance of lesions, there are still benefits if treatment is started after 72 hours.

Among them, people who are not treated during their first outbreak are more likely to experience severe or prolonged recurrences in the future, even if their initial symptoms were mild.

The CDC recommends three antiviral therapies for a first episode of genital herpes, regardless of the viral type. They are all taken by mouth. Medication doses are measured in grams (g) or milligrams (mg).

 Drug  Dose  Duration
Famvir (famciclovir) 250 mg three times daily 7–10 days
Valtrex (valacyclovir) 1 g (1,000 mg) twice daily 7–10 days
Zovirax (acyclovir) 400 mg twice daily 7–10 days

The drugs can be taken with or without food, but the doses need to be evenly spaced throughout the day (every 12 hours for twice-daily doses and every eight hours for thrice-daily doses). If needed, treatment can be extended if the lesions have not fully healed.

Recurrence

One of the key differences between genital herpes caused by HSV-1 and HSV-2 is that almost all cases of genital HSV-2 infections involve recurrence. By contrast, genital herpes caused by HSV-1 is less likely to recur.

In cases of recurrence, antivirals can be prescribed whenever an outbreak occurs, usually at lower doses or for shorter treatment periods. This is referred to as episodic therapy.

There are seven episodic therapies recommended for the treatment of HSV-2 recurrence.

 Drug  Dose  Duration
Famvir (famciclovir) 1 g two times daily 1 day
500 mg once on first day, followed by 250 mg twice a day for two days 3 days
125 mg two times daily 5 days
Valtrex (valacyclovir) 500 mg two times daily 3 days
1 g once daily 5 days
Zovirax (acyclovir) 800 mg three times daily 2 days
800 mg two times daily 5 days

If attacks are frequent and severe, your healthcare provider may recommend suppressive therapy in which an antiviral drug is taken every day to prevent a recurrence.

Studies have shown that suppressive therapy can reduce the frequency of genital herpes outbreaks by 70% and 80% while reducing the risk of infection to sexual partners.

The three suppressive therapies recommended for the treatment of recurrent HSV-2 are:

 Drug  Dose  Duration
Famvir (famciclovir) 500 mg two times daily Ongoing
Valtrex (valacyclovir) 500 mg two times daily Ongoing
Zovirax (acyclovir) 400–800 mg two or three times daily Ongoing

Summary

Herpes simplex virus type 2 (HSV-2) is the virus most commonly associated with genital herpes. While herpes simplex virus type 1 (HSV-1), the virus linked to cold sores, can also cause genital herpes, it is far less likely to cause recurrent outbreaks the way that HSV-2 can.

HSV-2 doesn't always cause symptoms. When it does, it can lead to an outbreak of blisters on the genitals or rectum that break open to cause painful, oozing sores. First outbreaks tend to be worse than subsequent ones.

HSV-2 can be passed during sex if a person is exposed to an open herpes sore. But, asymptomatic people with HSV-2 can also pass the virus to others during periods of viral shedding

Genital HSV-2 infections can be diagnosed with a physical exam, blood tests, and a swab of a herpes lesion. Treatment involves antiviral drugs, either taken when needed to treat acute episodes or taken daily to reduce the frequency of outbreaks.

A Word From Verywell

The diagnosis of genital herpes can cause extreme anxiety and stress in some people, particularly those who are just starting to date. If this is you, it is important to remember that millions of people have genital herpes and that having the disease doesn't mean that you are "tainted."

Coming to terms with genital herpes can take time, and it often helps to join a support group to educate yourself and get perspective on what it is like to live with this common viral disease.

A great resource is the Inspire support community facilitated by the American Sexual Health Association (ASHA). It is free to join and allows people with STIs a safe space to post questions and seek advice from others who fully understand what they are going through.

Frequently Asked Questions

  • Is genital herpes (HSV-2) curable?

    Genital herpes is not curable, but it can be managed with antiviral drugs like Zovirax (acyclovir) and Valtrex (valacyclovir). While first outbreaks can be severe, subsequent outbreaks tend to be milder. Over time, many people will have fewer and fewer attacks. Those who don't can take daily antiviral drugs to reduce the frequency of attacks by 70%–80%.

  • Is genital herpes caused by HSV-2?

    Herpes simplex virus type 2 (HSV-2) accounts for most cases of genital herpes. But, herpes simplex type 1 (HSV-1), the type linked to cold sores, can also be passed to the genitals during oral sex. Genital outbreaks caused by HSV-1 and HSV-2 are largely indistinguishable, but those caused by HSV-2 will almost always result in recurrent attacks.

  • How long does it take for HSV-2 to show up?

    The incubation period for herpes simplex virus type 2 (HSV-2) is between two and 12 days following exposure. Most cases of genital herpes will start within four days. With that said, many HSV-2 infections cause no symptoms even though the person can still pass the virus to others.

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