Genital Herpes

Original Author: Grace Fitzgerald
Last Updated: 13th February 2017
Revisions: 3

Genital Herpes is a sexually transmitted infection caused by the Herpes simplex virus. It is transmitted via skin-to-skin contact through vaginal, anal or oral sex. Once infected people may be asymptomatic for a long period of time, until the first flare up. Following the primary symptomatic infection, the virus can lie dormant until it recurs later in life causing recurrent outbreaks.

In this article we will discuss the pathophysiology underpinning genital Herpes simplex infection, signs and symptoms, alternative diagnoses, investigations and management.


Pathophysiology

There are two types of the Herpes simplex virus, HSV-1 and HSV-2. HSV-1 causes genital herpes and additionally it can affect areas around the mouth and nose causing cold sores. HSV-2 also affects the genital and anal areas causing genital herpes. This means that herpes can be spread to the genitalia via skin-to-skin genital contact, penetrative sex or oral sex with someone who suffers from cold sores.

HSV enters the body through small cracks in the skin or through the mucous membranes of the mouth, vagina, rectum, urethra or under the foreskin. After infecting the surface, the virus travels up the nearest nerve to the ganglion and remains there. This explains why the infection can stay dormant for so long, as here it cannot be reached by the immune system. During the reactivation of the virus, it travels back down the nerve onto the surface of the genitals once again to cause a symptomatic outbreak.

Asymptomatic shedding is also an important cause of transmission as many people can shed and transmit the virus even if they are unaware they have the infection.


Risk Factors

Genital herpes is spread by sexual contact and can still be transmitted with the use of barrier contraception, although this is less likely, it is possible, especially if the virus is present on genital areas not covered by the barrier, such as the thighs.

Having multiple sexual partners increases the risk of contracting genital herpes as well as other STIs.

Having oral sex with a partner suffering from cold sores also increases the risk of contracting HSV.


Clinical Features

Symptoms may not appear for months or even years after infection however some people will develop symptoms straight away.

Primary infection symptoms

The first time infection symptoms of genital herpes include –

  • Small red blisters around the genitals that are very painful and can form open sores
    • In males these are on the penis, anus, buttocks and thigh
    • In females these are on the vulva, clitoris, buttocks and anus
  • Vaginal or penile discharge
  • Flu-like symptoms, fever, muscle aches
  • Itchy genitals

After around 20 days the lesions crust and heal.

Lesions typical of a Herpes infection

Fig 1 – Lesions typical of a Herpes infection

Secondary (recurrent) infection symptoms

Once the primary infection has cleared the virus remains dormant in the body. HSV can therefore become reactivated and cause recurrent outbreaks.

These recurrent outbreaks are often shorter and less severe and over time outbreaks usually reduce in severity and length. This is largely due to antibody production increasing recognition of the virus and increasing the effectiveness of response.

The symptoms of the recurrent outbreaks include

  • Burning and itching around the genitals
  • Painful red blisters around the genitals

Cold sores

Cold sores are painful lesions around the mouth and nose that last between 7-10 days. Like genital herpes the virus is usually dormant with outbreaks occurring up to a few times a year. They are mainly caused by HSV-1 and can be occasionally caused by HSV-2. If someone suffering from cold sores gives oral sex to a partner, the partner is at risk of contracting genital herpes as a result.

The dormant aspect of the infection means people may contract herpes from a partner without knowing. As a result this can make a diagnosis of genital herpes quite shocking and very difficult for a patient.


Differential Diagnoses

There are many causes of genital ulceration including aphthous ulcers, the varicella-zoster virus, trauma and other vesiculobullous disorders.

Many outbreaks of herpes may indicate a weakened immune system and therefore an underlying diagnosis of HIV. This is something to consider when assessing a patient with more than 5 outbreaks of genital herpes in one year.


Investigations

Herpes is best diagnosed during the primary infection at a GUM clinic or GP surgery.

  • History – sexual partners, history of cold sores or similar symptoms and whether the patient has a history of any other STIs.
  • Swab from the open sore – if a patient presents with painful lesions indicative of Herpes simplex. This swab will be tested for the presence of HSV and PCR can differentiate between type 1 and 2. Even if this swab is negative, the diagnosis of herpes can still be made later on if flare-ups persist.

It may also be recommended to screen patients for other sexually transmitted infections, if the history suggests the patient may be at increased risk due to their or their partners behaviours.


Management

Antivirals and over the counter medications can be used to reduce symptom duration and severity during primary infection and recurrences.

Primary infection

When someone presents with primary infection, they can be treated with the antiviral drug, Aciclovir. This can be effective at reducing the number and size of the lesions caused by HSV. Once the primary infection has cleared up the patient should be offered a full sexual health screen and advice about preventing transmission of the infection to sexual partners – avoid all sexual contact during an outbreak, as the open sores are the most infective form of HSV. They should also be advised to disclose the infection to their recent and current sexual partners. Supportive measures including rest/time off work if systemically unwell are also important.

Recurrent outbreaks

Over the counter painkillerspetroleum jelly and ice packs are recommended to reduce the pain and discomfort of an infection.

If episodes are regular then episodic treatment is recommended. This involves taking Aciclovir as soon as symptoms begin to present to reduce the severity of outbreaks.

If outbreaks become very frequent (more than 6 times in a year) or are particularly severe then suppressive treatment is recommended. This involves taking daily doses of aciclovir to prevent new outbreaks.

Herpes in Pregnancy

If a pregnant woman has existing genital herpes and becomes pregnant, her baby should be protected from acquiring the infection due to the antibodies she will pass to the foetus through the placenta. However she may be required to still take Aciclovir. Vaginal delivery is offered to women with recurrent lesions at time of delivery although they may want to have a caesarean section. The risk of transmission is estimated at 0-3% transmission with vaginal birth.

If the mother contracts Herpes herself in the last trimester of pregnancy this is more dangerous for the baby. This is because the mother has not produced antibodies to pass onto the growing foetus. This means that the baby is a lot more likely to contract herpes during vaginal birth (2/5 chance) and so a caesarean section is recommended in this circumstance.

There are 3 forms of neonatal herpes; skin, eyes and mouth (SEM) herpes, disseminated (DIS) herpes affecting the internal organs, and CNS herpes affecting the nervous system and the brain and can lead to encephalitis. Antiviral treatment is usually sufficient for SEM herpes but mortality is estimated to be much higher for DIS and CNS herpes, especially if undiagnosed for some time.

Full RCOG guidelines regarding the management of herpes in pregnancy can be found here.

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