Natural history and clinical features

• Only a third of individuals appear to develop recognisable symptoms at the time of acquisition. Incubation of infection from acquisition to first clinical signs and symptoms in this minority ranges from 2 days to 2 weeks.
• Disease episodes may be initial or recurrent and symptomatic or asymptomatic.
• Prior infection with HSV-1 modifies the clinical manifestations of the first infection by HSV-2.
• After childhood, symptomatic primary infections with HSV-1 are equally likely to be acquired in the genital or oral areas.
• The majority of first episode infections of genital herpes in adults are due to HSV-1.
• Following primary infection, the virus becomes latent in local sensory ganglia, periodically reactivating to cause symptomatic lesions or asymptomatic (but infectious) viral shedding. Virus can be shed from the external genitalia, the anorectum, the cervix and urethra.
• The median rate for recurrence after a symptomatic first episode is 0.34 recurrence/month for HSV-2 (and is four times the recurrence rate for HSV-1). Recurrence rates decline with time in most individuals, although this pattern is variable.
• In some individuals, the number of days when the virus is shed asymptomatically exceeds the number of days of symptomatic shedding.
• Asymptomatic shedding probably plays a significant role in onward transmission.

Signs and Symptoms

• The patient may be asymptomatic and the disease unrecognised.
• Local symptoms may consist of
• blisters or painful ulceration of external genitalia or perianal region
• dysuria
• vaginal or urethral discharge (please note this may not need immediate testing for other causes of discharge)
• Proctitis – check for HSV in all cases
• Blisters and ulceration may also involve the cervix and / or rectum.
• Systemic symptoms of fever and myalgia are more common in
• those who present with a first episode with either HSV I or HSV II and no pre existing antibodies to either type, relative to
• those with a first episode with either HSV I or HSV II with pre existing antibodies to the other type, or
• those who present with recurrent disease.
• Lesions and lymphadenitis are usually bilateral in first episodes.
• It is usual for lesions to affect favoured sites in recurrent disease. They may alternate between sides but are usually unilateral for each episode.
• Lesions of recurrent episodes may be small and may resemble non-specific erythema, erosions or fissures.
• Recurrent episodes are limited to the infected dermatome.

Complications

• Superinfection of lesions with candida or streptococcal species.
• Urinary retention (result of severe pain or autonomic neuropathy).
• Autoinoculation to fingers and adjacent skin, e.g. thighs.
• Aseptic meningitis