Genital Herpes Simplex

This document is mainly based on the RCGP¹ and GUM guidance.²

Genital Herpes Simplex is caused by infection with the Herpes simplex virus (HSV).

• Herpes simplex virus (HSV) is sub-divided into HSV type 1 (HSV-1) and HSV type 2 (HSV-2).
• Type 1 usually affects the oral region and causes cold sores (herpes labialis).
• Type 2 is associated with genital infection (penis, anus, vagina).
• However, both can infect the mouth and/or genitals due to oral sex or autoinoculation.
• Up to 50% of first episode genital herpes in the UK is attributable to HSV type 1.³

• Genital HSV is the most common ulcerative sexually transmitted infection in the UK.⁴
• In 2005 in the UK, highest rates of newly diagnosed cases were seen in 20-24 year olds.⁴
• Diagnosis rates of genital HSV at GUM clinics in the UK have increased 5 fold in males and 21 fold in females between 1971 and 2005.⁴
• In 2005, the female to male ratio was 1.5:1.⁴
• Rates of first episode genital HSV were highest in the London region in 2005 (54/100,000 for men and 75/100,000 for women) and at least twice those in all other regions.⁴

• Close physical contact with an individual already infected with HSV.
• Includes through vaginal, anal and oral sex, close genital contact and contact with other sites such as eyes and fingers.
• The individual transmitting the infection may be asymptomatic but still shedding the virus. (This is how most transmission of genital HSV occurs. Asymptomatic shedding occurs in 80% or people with HSV-2.)
• Transmission from asymptomatic individuals in monogamous relationships can occur after several years and cause considerable recrimination and distress.

Risk factors for acquiring infection

• Sexual promiscuity.
• Unprotected sexual encounters.
• Female sex.
• HIV positive HSV-2 seropositive men are more likely to have symptomatic or asymptomatic viral shedding (i.e. are more likely to be infective).⁵
• There is evidence that genital HSV increases the risk of acquiring HIV infection and that people with both HSV and HIV are more likely to transmit HIV infection.⁶
• Genital herpes caused by HSV-2 infection has also been shown to double the risk of becoming infected with HIV through sexual transmission.⁷

Usually presents as multiple painful ulcers.

Primary infection

• This is the first time the virus is acquired.
• May be asymptomatic (common). If this is the case, the first symptomatic episode is called a non-primary first episode. Evidence of previous infection is shown by the presence of type-specific antibodies at the time of presentation.
• Symptoms include:
  • Febrile flu-like prodrome (5-7 days).
  • Tingling neuropathic pain in genital area/buttocks/legs.
  • Extensive bilateral crops of blisters/ulcers in the genital area (including the vagina and cervix in women).
  • Tender lymph nodes (inguinal).
  • Local oedema.
  • Dysuria.
  • Vaginal or urethral discharge.
• Can last up to 4 weeks if not treated.

Recurrent infection

• Following primary infection, the virus becomes latent in local sensory ganglia.
• There is periodic reactivation which can cause symptomatic lesions or asymptomatic, but still infectious, viral shedding.
• Episodes usually shorter (up to 10 days).
• Symptoms may be mild and self-limiting.
• Lesions tend to be unilateral.
• Median recurrence rate after a symptomatic first episode is:
  • HSV 2: 0.34 recurrences per month (roughly 4 attacks in next 12 months).
  • HSV 1: 0.08 recurrences per month (roughly 1 attack in next 12 months).⁸
• Attacks usually become less frequent over time.
• Genital HSV caused by type 1 infection recurs less often.⁹

• Candida and scabies produce excoriation but not vesicles.
• The ulcers of syphilis are painless.
• Reiter's syndrome, Behçet's syndrome, drug reactions, chancroid, lichen planus, lichen simplex, lichen sclerosis, trauma (including dermatitis artefacta), and malignancy can cause genital ulceration.
• Herpes zoster is usually unilateral and confined to one dermatome.

There is no cure for genital HSV. Infection is lifelong although most people will eventually stop having recurrences.

Primary infection

Guidance from the Royal College of General Practitioners document states:¹

• Refer a patient with suspected genital HSV infection to a Genito-Urinary Medicine (GUM) clinic the same day (ring to arrange).
• If a same/next day appointment is not possible, then:
  • Confirm diagnosis: Swab base of ulcer (pop blister if necessary) for HSV (a special swab with transport medium is required - discuss this with your local laboratory). Maintenance of the cold chain and rapid transport of specimens within 24 hours is needed. Viral culture is still the gold standard for diagnosis but PCR has the highest detection rate.
  • Supportive treatment: Advise saline bathing (1 teaspoon of salt in 1 pint warm water). Prescribe analgesia and consider topical Lignocaine 5% ointment if very painful. Micturition whilst sitting in a bath can help prevent urinary retention.
  • Antiviral therapy: There is no role for topical antivirals. Give oral anti-herpes virus treatment if there are early symptoms (i.e. within 5 days of onset of symptoms, or if new lesions are still forming). Usually aciclovir 200mg orally 5 times per day for 5 days.¹ Oral valaciclovir 500mg twice daily for 5 days gives higher antiviral levels than aciclovir but is much more expensive (as is famciclovir). In HIV positive patients, some clinicians advocate a 10 day course of treatment. A 10 day course may also be needed if new lesions continue to form or symptoms and signs are severe. Antiviral therapy reduces the severity and duration of episodes but does not alter the natural history of the disease.^10,11,12
  • Arrange follow-up: Arrange appointment at a GUM clinic in 2 to 3 weeks to allow patient education and a full sexually transmitted infection screen. Advise patient to report to a GUM clinic sooner if the symptoms are not resolving. Provide written self-help information to the patient if possible.

Recurrent infection

• Supportive treatment only may be required (saline bathing, vaseline prn to ease pain due to friction, analgesia).
• Episodic treatment for each attack:
  • Treatment with e.g. aciclovir 200mg orally 5 times per day for 5 days.
  • Advisable to give the patient a prescription so that they can start taking the treatment at first signs of a recurrence.
  • Diary keeping of attack frequency may be helpful.
• Suppressive treatment:
  • May be needed (usually if >6 attacks per year).
  • This has to be a balance of the frequency of attacks and symptoms against the cost and inconvenience of treatment: e.g. aciclovir 400mg orally twice daily, give 3 months supply at a time.
  • Discontinue after 12 months to reassess attack frequency.
  • Minimum period of reassessment should include 2 further attacks.
  • If recurrence rate is unacceptably high, suppressive treatment can be restarted.
  • Suppressive treatment also reduces the risk of asymptomatic shedding.

Counselling

• Diagnosis can cause distress.
• Contact tracing is needed (offer serological testing to asymptomatic contacts).
• Written information should be given to the patient.
• Need to cover:⁹
  • Natural history of genital HSV.
  • The role of asymptomatic viral shedding in sexual transmission (more common in genital HSV-2 and in first year after infection).
  • The fact that a first episode of genital HSV does not necessarily imply recent infection.(Relationship issues need to be addressed).
  • Use of antiviral drugs for symptom control including prescription in reserve for recurrent attacks and possible longer-term suppressive treatment.
  • If in a stable relationship, the other partner may not necessarily be infected. The daily use of valaciclovir by the infected partner can reduce the risk of transmission of HSV-2.¹³
  • In couples not using suppressive antiviral treatment or condoms, the risk of transmission from an infected man to a woman is 7% per year and that for a woman to a man is 3%.¹⁴
  • Avoid sexual contact during symptomatic recurrences.
  • Inform current or new sexual partners.
  • Condoms may reduce risk of transmission.
  • Pregnancy issues. Please refer to separate information on Herpes Simplex and Pregnancy. All women with a diagnosis should advise their GP and Midwife of this at first antenatal appointment to reduce the risk of neonatal infection.

Role of serology in HSV detection

• Type specific serology tests can identify those with asymptomatic infection and can distinguish between the two types of HSV.
• Serological tests may take up to 12 weeks to become positive after primary infection.
• It may be useful:
  • If the patient's partner has genital herpes and the patient wants to know if they have been infected.
  • If there are recurrent/atypical genital ulcers with negative culture or PCR results.
  • To screen people at high risk of sexually transmitted infection.
  • To test pregnant women with undiagnosed genital herpes.

• Autonomic neuropathy, resulting in urinary retention. (Suprapubic catheterisation is preferred due to reduced risk of ascending infection, less painful procedure, allows normal micturition to be restored without multiple removals/recatheterisations).
• Aseptic meningitis.
• Spread to extra-genital areas (in theory through self-inoculation).
• Secondary bacterial or fungal infection.
• Perinatal transmission if woman is pregnant.
• Encephalitis or disseminated infection (rare, more likely in immunocompromised).
• Psychological and psychosexual problems.

• Reducing numbers of sexual partners.
• Using condoms.
• Avoiding sex with someone who has active genital herpes or active oral herpes.
• There is current research into vaccine production.