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Overview
Genital herpes is a common sexually transmitted infection (STI) caused by the herpes simplex virus (HSV): HSV-1 and HSV-2.
HSV-1 often spreads through oral contact and causes infections in or around the mouth (known as oral herpes or cold sores). It can also cause genital herpes.
HSV-2 often spreads through sexual contact and causes genital herpes.
The infection can cause painful blisters or ulcers that can recur over time. Most cases of recurrent genital herpes are caused by HSV-2, but an increasing proportion has been attributed to HSV-1 infection, especially among men who have sex with men (MSM) and young women. It is treatable but not curable.
Disease epidemiology
According to 2016 data from the World Health Organization, approximately 67% of the global population under the age of 50 had a HSV-1 infection (oral or genital), with the majority of these infections acquired during childhood.
Genital herpes, caused by HSV-2, affects an estimated 13% of people aged 15 to 49 worldwide. HSV-2 infections are more common in women than in men, attributed to the higher efficiency of sexual transmission from men to women. Although the prevalence of HSV-2 increases with age, the majority of new infections occur among adolescents.
Pathogen(s)
HSV-1 and HSV-2.
Transmission
The primary mode of transmission of both HSV-1 and HSV-2 is via direct contact of open lesions. It can occur through genital to genital, mouth to genital, genital to anal and mouth to anal contact. HSV-1 and HSV-2 can also be shed from normal-appearing oral or genital mucosa or skin.
Incubation period: 2 to 14 days.
Infectious period: Primary genital lesions are infectious for 7 to 10 days, while those with recurrent disease may be infectious for 4 to 7 days with each episode. Cold sores may be infectious for up to seven weeks after recovery from stomatitis.
Clinical features
Most individuals with HSV infection experience either no or mild symptoms. Consequently, they may transmit the virus to their partners unknowingly.
First-episode genital herpes may either be primary or non-primary. Primary genital herpes is defined as an infection occurring in persons with no prior exposure to either HSV-1 or -2. Non-primary genital herpes is defined as the first-genital episode in persons who have evidence of prior HSV infection at another body site with either HSV-1 or -2.
First-episode genital herpes is often severe, presenting with multiple grouped vesicles, which rupture easily leaving painful erosions and ulcers.
Females: lesions occur on the vulva, vagina, and cervix.
Males: lesions occur mainly on the prepuce and sub-preputial areas of the penis.
Healing of uncomplicated lesions take two to four weeks. Complications may include:
Aseptic meningitis
Autonomic neuropathy resulting in urinary retention and autoinoculation to fingers
Recurrent episodes are usually less severe. The vesicles or erosions develop on a single anatomical site, and these usually heal within 10 days. Median recurrence rate is approximately four recurrences per year for HSV-2 and is four times more frequent than the recurrence rate for HSV-1.
HSV is a significant cause of proctitis in MSM, more commonly found in HIV-positive than HIV-negative MSM. Only 32% of MSM with HSV-associated proctitis had visible external anal ulceration.
Risk factors
Risk factors include:
Sexual contact with an infected person
Engaging in unprotected oral, anal, or vaginal sex
Having multiple sex partners
History or current presence of other STIs
Diagnosis
Clinical diagnosis of genital herpes can be difficult because the self-limited, recurrent, painful, and vesicular or ulcerative lesions classically associated with HSV are absent in many infected persons at the time of clinical evaluation.
Tests for diagnosis include:
Nucleic acid-based amplification testing (NAAT) as the preferred method for genital herpes
Polymerase chain reaction (PCR) is the test of choice for diagnosing HSV infections affecting the central nervous system and systemic infections (e.g., meningitis, encephalitis, and neonatal herpes)
Type-specific serologic tests (TSSTs) can be used to aid in the diagnosis of HSV infection in the absence of genital lesions
Serology may be useful in certain clinical situations:
Recurrent genital symptoms or atypical symptoms with negative HSV PCR or culture
Clinical diagnosis of genital herpes without laboratory confirmation
Asymptomatic partners of serodiscordant couples of genital herpes, including women who are planning for pregnancy or are pregnant
STI evaluation for persons with multiple sexual partners, persons with HIV infection and MSM at increased risk for HIV acquisition
Pregnant women presenting with first episode of genital herpes in the third trimester.
Treatment and management
For general treatment measures, patients are advised to clean the affected areas with normal saline, take analgesics, and/or receive treatment for any secondary bacterial infection.
Systemic antiviral drugs can partially control the signs and symptoms of genital herpes when used to treat first clinical and recurrent episodes, or when used as daily suppressive therapy. However, these drugs neither eradicate latent virus nor affect the risk, frequency, or severity of recurrences after the drug is discontinued.
Recommended regimens for first episode of genital herpes:
Acyclovir 400mg orally 3 times a day, for 7 to 10 days
Valacyclovir 1g orally 2 times a day, for 7 to 10 days
Famciclovir 250mg orally 3 times a day, for 7 to 10 days
For optimal benefit, the treatment should be started within 48 to 72 hours of onset of lesions, when new lesions continue to form or when symptoms and signs are severe. Treatment can be extended if healing is incomplete after 10 days of therapy.
Recurrent genital herpes:
Most recurrent attacks are mild and can be managed with general measures. Routine use of specific treatment is not necessary. Management should be decided with the patient.
Follow-up:
Counselling of infected persons and their sex partners is crucial for management. The goals of counselling are to help patients cope with the infection and prevent sexual and perinatal transmission.
Refer to the Department of Sexually Transmitted Infections Control (DSC)'s website for more information on the treatment options for genital herpes.
Precaution, prevention, and control
Prevention of genital herpes:
Abstaining from sexual activity during symptomatic periods
Using condoms consistently and correctly when engaging in sexual activity
Limiting the number of sex partners
Getting tested for STIs regularly
Management of sexual contacts:
Sexual partners of patients with genital herpes are likely to benefit from evaluation and counselling. They should be assessed for history of typical and atypical genital lesions, encouraged to self-examine for lesions and seek medical attention early if lesions appear. TSSTs may be useful in counselling couples.
Notification
Genital herpes is not a notifiable disease. Please refer to the Infectious Disease Notification for more information.
Resources
Refer to DSC’s website for more information on the treatment options for genital herpes.
References
Centers for Disease Control and Prevention. STI treatment guidelines: Genital herpes. 2021.
Department of Sexually Transmitted Infections Control (DSC). STI management guidelines 7th edition. 2021.
World Health Organization. Herpes simplex virus. 2023.