Background Information
Definition
Genital herpes is an STI caused by herpes simplex virus infection of the anogenital area.
Aetiology
Herpes simplex virus (HSV) is a double-stranded DNA virus
Types of HSV:
- HSV-1 – most common cause of genital herpes nowadays (same as oral herpes)
- HSV-2 – historically the most common cause of genital herpes, and more likely to cause recurrent anogenital symptoms
Clinical Features
Typical features:
- Multiple, painful genital blisters in groups
- Location: external genitalia / perineum / perianal region
- Blisters quickly burst to leave erosions and ulcers
- Tender bilateral inguinal lymphadenopathy
- Dysuria
- Vaginal / urethral discharge
- Systemic symptoms (headache, malaise and/or fever)
Primary vs recurrent genital herpes
- In recurrent episodes, genital lesions are usually less severe and localised to the same dermatome during each episode
- In recurrent episodes, lesions usually heal within 6-12 days, while it could last up to 3 weeks in primary herpes
- Systemic symptoms are more common with primary herpes
- Prodromal tingling / burning pain in the genital area / lower back / buttocks / upper thighs may occur up to 48 hours before lesions appear in recurrent episodes
Diagnosis
Investigation and Diagnosis
Refer suspected cases to GUM
- 1st line: viral swab for PCR
- Other investigations
- HSV serology (esp. in 3rd trimester and if type is not known)
- Full STI screening
Do not delay treatment whilst awaiting test results.
Management
Conservative Management – ALL Patients
General advice:
- Increase fluid intake
- Urinate in a bath or with water flowing over the area
- Abstinence from sexual contact during lesion recurrences / prodromes
Self-care measures
- Saline bathing
- Analgesia (paracetamol / ibuprofen)
- Topical petroleum jelly / anaesthetic agent (e.g. 5% lidocaine ointment)
NSAIDs should be avoided from 20 weeks of gestation onwards due to the risk of premature ductus arteriosus closure and oligohydramnios
Primary Herpes Infection (Initial Episode)
Antiviral Therapy
Antiviral therapy is indicated in ALL pregnant patients with primary herpes infection. There are 2 phases of antiviral therapy:
- Initial: acute antiviral treatment
- Followed by suppressive antiviral therapy later on
Do NOT delay acute/episodic treatment while awaiting microbiology results (i.e. viral PCR). It should be initiated once genital herpes is suspected clinically.
1. Acute Antiviral Treatment
5-day course of:
- Oral aciclovir 400mg TDS for 5 days OR
- Oral valaciclovir 500mg BD for 5 days
IV antivirals are reserved for disseminated HSV infections.
Note that the following antivirals should NOT be used in pregnancy:
- Ganciclovir is contraindicated (also note that it is used to treat CMV, not HSV)
- Famciclovir has limited safety data, thus avoided
2. Suppressive Antiviral Treatment
The purpose of suppressive antiviral treatment is to reduce viral shedding, reduce risk of neonatal transmission (highest if primary infection is acquired within 6 weeks of delivery), and reduce the risk of recurrence.
Choice of antiviral: oral aciclovir or valaciclovir with a lower daily dose (compared to acute treatment)
The initiation timing and treatment duration depend on when the infection occurred:
- 1st / 2nd trimester infection → start from 32 weeks of gestation and continue until delivery
- If there is a high risk of premature delivery → start from 22 weeks of gestation instead
- 3rd trimester infection → start immediately and continue until delivery
Note that the following antivirals should NOT be used in pregnancy:
- Ganciclovir is contraindicated (also note that it is used to treat CMV, not HSV)
- Famciclovir has limited safety data, thus avoided
Mode of Delivery
Caesarean section is the recommended mode of delivery to reduce risk of transmission if ANY of the following are present:
- 3rd trimester infection (from 28 weeks onwards; esp. if ≤ 6 weeks to delivery)
- Delivery expected within the next 6 weeks
If Caesarean section is not indicated, expectant vaginal delivery is the primary option
Recurrent Genital Herpes
Recurrent genital herpes is defined as the recurrence of clinical symptoms caused by the reactivation of a pre-existing HSV-1 or HSV-2 infection following a period of latency.
It can be difficult to distinguish between primary and recurrent herpes, patients may have had a previous asymptomatic infection. Type-specific HSV serology can help determine prior exposure and clarify the patient’s status.
Management of recurrent genital herpes is significantly less aggressive compared to primary herpes.
- Acute antiviral therapy is NOT routinely indicated
- Most recurrent episodes are short-lived and resolve within 7-10 days without antivirals
- Acute antiviral therapy is only used to manage severe symptoms
- C-section is not recommended solely to reduce the risk of transmission
Rationale:
The risk of neonatal transmission is very low (0–3% with vaginal delivery), as the fetus is protected by maternal antibodies transferred across the placenta. There is no evidence of an increased risk of congenital abnormalities associated with recurrent maternal genital herpes.
Suppressive Antiviral Therapy
Suppressive antiviral therapy is routinely recommended for ALL pregnant women with:
- Known diagnosis of genital herpes, and
- Regardless of whether they experience recurrences during the current pregnancy
Choice of antiviral: oral aciclovir or valaciclovir
Timing:
- Standard: start from 32 weeks gestation and continue until delivery
- High-risk of preterm delivery: start from 22 weeks
Acute Flare-Ups Management
Note that most recurrent episodes are short-lived and resolve within 7-10 days without antivirals.
Offer the same conservative management:
- General advice:
- Increase fluid intake
- Urinate in a bath or with water flowing over the area
- Abstinence from sexual contact during lesion recurrences / prodromes
- Self-care measures
- Saline bathing
- Analgesia (paracetamol / ibuprofen)
- Topical petroleum jelly / anaesthetic agent (e.g. 5% lidocaine ointment)
DO NOT routinely offer acute antiviral therapy in recurrent genital herpes.
Acute antiviral therapy (5-day course of oral aciclovir or valciclovir) should only be considered to manage severe symptoms, based on the individual’s clinical condition.
Breastfeeding and Genital Herpes
Antivirals (aciclovir and valaciclovir) used to treat herpes are not harmful to infants
It is safe to breastfeed if there is no herpetic lesion on the breast
- Avoid milk contamination (e.g. touching the breast during hand expression / via the pump)
References