Genital herpes guide: Risk factors and clinical manifestations

On this page:

• Risk factors
• Transmission
• Clinical manifestations
  • Signs and symptoms
  • First symptomatic episodes
  • Recurrences
  • Neonatal herpes
• References

Risk factors

Common risk factors for genital herpes include^{Footnote 1Footnote 2}:

• Sexual contact with a person with HSV-1 or HSV-2
• Oral, anal or vaginal sex without the use of barrier protection (condom, dental dam)
• Multiple sexual partners
• Anonymous sexual partners
• Presence or history of another sexually transmitted or blood-borne infection (STBBI)

Females are at higher risk of acquiring genital herpes from a male partner than vice versa. Studies of heterosexual couples with one partner who had symptomatic recurrent genital HSV-2 (“source partner”) revealed annual transmission rates of 11–17% in couples with a male source partners and 3–4% in couples with a female source partners^{Footnote 3Footnote 4}.

Transmission

HSV transmission occurs via skin-to-skin contact during periods of symptomatic and asymptomatic viral shedding. Asymptomatic shedding is more frequent closer to the time of acquisition^{Footnote 5} and with genital HSV-2^{Footnote 6Footnote 7}. In one study, 70% of transmissions were attributed to sexual contact during periods of asymptomatic viral shedding^{Footnote 4}.

HSV-1 is known for causing oro-labial herpes and is usually acquired through nonsexual contact (including kissing) during childhood^{Footnote 8}. Genital HSV-1 is commonly acquired through receptive oral-genital contact and can also result from genital-genital contact^{Footnote 9Footnote 10Footnote 11}.

HSV-2 is generally transmitted through genital-genital contact; oral-genital transmission is rare^{Footnote 12}.

Having one type of HSV does not fully protect against acquisition of the same type at another site or of another type, but the signs and symptoms of a second infection may be less severe^{Footnote 13}.

Both HSV-1 and HSV-2 can be transmitted vertically and lead to neonatal disease. In the absence of intervention, the rate of vertical transmission for HSV-1 or HSV-2 acquired during the second half of pregnancy is 30-50%^{Footnote 14Footnote 15Footnote 16}.

Clinical manifestations

The incubation period for newly acquired (primary) infections varies from 1 to 26 days with a median of 6 to 8 days^{Footnote 17}. After initial exposure, HSV enters the mucocutaneous tissues and replicates. After the initial replication, HSV enters a latent phase in sensory ganglia where it may remain dormant for years^{Footnote 17}. Episodic reactivation may cause asymptomatic or symptomatic episodes of viral shedding^{Footnote 18}.

A first-episode primary genital infection results when people without HSV-1 or HSV-2 antibodies acquire either type of virus in the genital tract. A first-episode non-primary infection is the first clinically evident episode of genital herpes in an individual who has pre-existing HSV antibodies (because of prior infection). The antibodies may be homologous (the same type as a prior infection) or heterologous (the episode is caused by infection with a different type)^{Footnote 11}. A recurrence is a clinically evident episode which is due to viral reactivation in sensory ganglia^{Footnote 17Footnote 19} and can be the first recognized episode.

Signs and symptoms

A cluster of vesicles or pustules on an erythematous base is suggestive of herpes. Clinical manifestations of genital herpes infection vary widely, and it can be difficult to distinguish between primary, non-primary and recurrent episodes due to overlapping presentations. In general, primary episodes have more systemic symptoms and lesions will be at different stages of healing^{Footnote 20}. Recurrent episodes are typically unilateral whereas primary episodes are frequently bilateral^{Footnote 20}.

HSV may cause severe systemic disease in neonates and immunocompromised people^{Footnote 21}.

First symptomatic episodes

Primary infection

A primary (newly acquired) infection may be asymptomatic^{Footnote 19} and may go undiagnosed. Approximately 60% of new HSV-2 infections diagnosed by seroconversion are asymptomatic and 20% of those that are symptomatic have atypical presentations^{Footnote 11}.

Common signs and symptoms of a primary genital infection include^{Footnote 11}:

• Extensive, painful, bilateral vesiculo-ulcerative genital or anal lesions (may involve the exocervix)
• Systemic symptoms: fever, malaise, myalgia and headache (about 67% of cases)
• Tender inguinal lymphadenopathy (about 80% of cases)

Atypical HSV-2 presentations may include genital pain, urethritis, cervicitis or aseptic meningitis^{Footnote 11}.

Without treatment, the mean duration of symptoms for a primary infection is 17–20 days^{Footnote 11}.

Complications of primary infection include^{Footnote 11}:

• Meningitis (16–26% of cases)
• Extragenital lesions (10–28% of cases)

Non-primary infection

Compared to a primary episode, signs and symptoms associated with a non-primary episode don’t last as long, are less severe and less extensive. Systemic symptoms occur in 16% of people^{Footnote 11}.

Without treatment, the mean duration of symptoms for a non-primary episode is 16 days^{Footnote 11}.

Complications of a non-primary episode include^{Footnote 11}:

• Meningitis (1% of people)
• Extragenital lesions (8% of people)

Recurrences

Recurrences are clinically evident episodes which are due to viral reactivation in sacral sensory ganglia^{Footnote 17Footnote 19}. A recurrence may be associated with factors such as menstruation, emotional stress, illness (especially with fever), sexual intercourse, surgery and the use of some medications^{Footnote 22}.

Approximately 70–90% of those with HSV-2 and 20–50% of those with HSV-1 will have recurrences within the first year after primary infection^{Footnote 23Footnote 24Footnote 25}. Genital HSV-2 is also associated with more frequent subclinical viral shedding.

Recurrences are characterized by^{Footnote 11}:

• Prodromal symptoms (focal burning, itching, tingling, hyperesthesia or dysesthesia or vague discomfort) lasting one (1) to two (2) days (43–53% of cases)
• Unilateral, localized small erythematous patch, painful genital vesicles and ulcers^{Footnote 11} along the distribution of the anterior or posterior branches of sacral nerves 2 or 3^{Footnote 26Footnote 27}
• Systemic symptoms (5–12% of cases)

Without treatment, the mean duration of symptoms for a recurrence is 9–11 days^{Footnote 11}.

Neonatal herpes

Most neonatal herpes infections present after a seemingly healthy neonate has left the hospital. Initial symptoms usually present by 4 weeks of age, but occasionally don’t present until 4 to 6 weeks of age^{Footnote 28Footnote 29}.

Typical presentations include vesicular rash, sepsis-like manifestations and seizures^{Footnote 30Footnote 31Footnote 32Footnote 33}. Infection can be localized to skin, eyes, or mouth (60% of infants)^{Footnote 34}; involve the central nervous system with or without skin infection (23% of infants)^{Footnote 34}; or involve multiple organs and systems as result of disseminated infection (17% of infants)^{Footnote 34}.

Without treatment, nearly 60% of infants with HSV will die^{Footnote 35}. Approximately 70% of untreated infants with herpes encephalitis will experience severe or fatal complications^{Footnote 29Footnote 36Footnote 37}. In a Canadian study, almost 40% of treated infants had neurologic damage^{Footnote 34}.

References