Overview
Genital Herpes (HSV)
1. Clinical Overview
Summary
Genital herpes is a sexually transmitted infection caused by herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2). After primary infection, the virus establishes lifelong latency in the sacral ganglia, with periodic reactivations causing recurrent episodes.
Key Facts
| Aspect | Detail |
|---|---|
| Cause | HSV-2 (majority), HSV-1 (increasing - oral-genital transmission) |
| Latency | Sacral nerve root ganglia (S2-S4) |
| Transmission | Skin-to-skin contact; can shed asymptomatically |
| Cure | None - lifelong infection |
| Major Concerns | Neonatal herpes, psychological impact |
Clinical Pearls
- Primary vs Recurrent: Primary infection is more severe and systemic
- Asymptomatic shedding: Transmission can occur without visible lesions
- HSV-1 genitally: Recurs less frequently than HSV-2
- Neonatal herpes: High mortality - Caesarean if active lesions at delivery
2. Epidemiology
Prevalence
| Population | Prevalence |
|---|---|
| HSV-2 seroprevalence (adults) | 10-20% worldwide |
| Symptomatic infection | Only 10-25% of seropositive individuals |
| HSV-1 causing genital herpes | Increasing (now ~50% of new cases) |
Risk Factors
| Risk Factor | Association |
|---|---|
| Multiple sexual partners | Increased transmission risk |
| Unprotected intercourse | Higher risk |
| Female sex | Higher susceptibility |
| HSV-2 seronegative partner | Discordant couples at risk |
| Immunocompromised | More severe, prolonged episodes |
3. Pathophysiology
Infection & Latency
Primary Infection (Genital Epithelium)
↓
Local Viral Replication → Vesicle Formation
↓
Retrograde Axonal Transport
↓
Latency in Sacral Ganglia (S2-S4)
↓
Periodic Reactivation (Triggers: stress, illness, UV, menses)
↓
Anterograde Transport to Epithelium
↓
RECURRENT LESIONS (or Asymptomatic Shedding)
Reactivation Triggers
| Trigger | Mechanism |
|---|---|
| Stress | Immune modulation |
| Intercurrent illness | Immune distraction |
| UV exposure | Local immune suppression |
| Menstruation | Hormonal influence |
| Immunosuppression | Direct reactivation |
4. Clinical Presentation
Primary Infection
| Feature | Description |
|---|---|
| Incubation | 2-14 days after exposure |
| Prodrome | Tingling, burning in genital area |
| Lesions | Multiple painful vesicles → ulcers → crusts |
| Distribution | Bilateral, extensive |
| Lymphadenopathy | Inguinal, bilateral, tender |
| Systemic symptoms | Fever, malaise, myalgia |
| Duration | 2-4 weeks untreated |
| Dysuria | Common (especially women) |
| Urinary retention | Rare but serious (sacral radiculopathy) |
Recurrent Episodes
| Feature | Description |
|---|---|
| Severity | Milder, shorter than primary |
| Prodrome | Often present (tingling 24-48 hours before) |
| Lesions | Fewer lesions, unilateral, clustered |
| Duration | 5-10 days |
| Frequency | Highly variable (HSV-2: ~4/year; HSV-1: ~1/year) |
| Systemic symptoms | Usually absent |
5. Clinical Examination
Findings
| Location | Findings |
|---|---|
| Genital | Grouped vesicles on erythematous base → shallow ulcers |
| Cervix/vagina | May be affected (often missed) |
| Perianal | If receptive anal intercourse |
| Lymph nodes | Tender inguinal lymphadenopathy |
Differential Diagnosis
| Condition | Distinguishing Features |
|---|---|
| Syphilis (chancre) | Painless, solitary ulcer |
| Chancroid | Painful, ragged ulcer, purulent |
| Behçet's disease | Recurrent oral + genital ulcers |
| Fixed drug eruption | History of medication |
| Candidiasis | Typically non-ulcerative |
6. Investigations
Diagnosis
| Test | Notes |
|---|---|
| Viral PCR (swab of lesion) | Gold standard, highly sensitive |
| Viral culture | Less sensitive, useful for antiviral resistance |
| Type-specific serology | Useful if lesions healed; detects IgG |
Interpretation of Serology
| Result | Interpretation |
|---|---|
| HSV-2 IgG positive | Past/current genital infection likely |
| HSV-1 IgG positive | Oral or genital HSV-1 (cannot distinguish) |
| IgM | NOT useful (cross-reactive, unreliable) |
7. Management
Primary Episode
| Medication | Dose | Duration |
|---|---|---|
| Aciclovir | 400mg TDS | 5 days (extend if not healed) |
| Valaciclovir | 500mg BD | 5 days |
| Famciclovir | 250mg TDS | 5 days |
Supportive Measures
| Measure | Purpose |
|---|---|
| Salt baths | Symptom relief |
| Topical lidocaine (Instillagel) | For dysuria |
| Oral analgesia | Paracetamol, ibuprofen |
| Catheterisation | If urinary retention |
Recurrent Episodes
| Option | Indication |
|---|---|
| Episodic treatment | Start at prodrome, same doses as above |
| Suppressive therapy | ≥6 episodes/year or significant impact |
Suppressive Therapy
| Medication | Dose |
|---|---|
| Aciclovir | 400mg BD |
| Valaciclovir | 500mg OD |
Pregnancy Management
| Scenario | Management |
|---|---|
| Primary in third trimester | Caesarean section (high neonatal risk) |
| Primary earlier in pregnancy | May deliver vaginally if no lesions at term |
| Recurrent herpes | Vaginal delivery usually safe (low neonatal risk) |
| Active lesions at delivery | Caesarean recommended |
| Suppressive therapy | From 36 weeks if recurrent (aciclovir 400mg TDS) |
8. Complications
| Complication | Notes |
|---|---|
| Urinary retention | Sacral radiculopathy (rare) |
| Meningitis | Benign, aseptic (Mollaret's meningitis if recurrent) |
| Neonatal herpes | Encephalitis, disseminated disease - high mortality |
| Autoinoculation | Finger lesions (herpetic whitlow) |
| Psychological impact | Significant stigma, anxiety |
| Erythema multiforme | Recurrent HSV can trigger |
9. Prognosis & Outcomes
| Factor | Outcome |
|---|---|
| Primary infection | Resolves; virus latent for life |
| Recurrence frequency | Decreases over years |
| HSV-2 vs HSV-1 (genital) | HSV-2 recurs more frequently |
| Suppressive therapy | 70-80% reduction in recurrences |
| Psychological support | Important component of care |
10. Evidence & Guidelines
| Organisation | Key Points |
|---|---|
| BASHH | UK management guidelines |
| IUSTI | European guidance |
| CDC | US recommendations |
Key Advice
- Inform sexual partners
- Cannot cure, but can manage well
- Risk of transmission even when asymptomatic (condoms reduce but don't eliminate risk)
- Suppressive therapy reduces transmission by ~50%
11. Patient / Layperson Explanation
What is genital herpes? It is a viral infection caused by the herpes simplex virus (HSV). It causes painful blisters and sores on the genitals.
How is it spread?
- Through skin-to-skin contact during sex (vaginal, oral, or anal)
- You can pass it on even without visible sores (asymptomatic shedding)
What happens after infection?
- First episode is usually the worst
- The virus stays in your body forever but is dormant most of the time
- It can reactivate, causing recurrent outbreaks (usually milder)
- Over time, outbreaks usually become less frequent
Is there a cure? There is no cure, but antiviral medication can:
- Shorten and reduce severity of outbreaks
- Be taken daily to prevent frequent recurrences
- Reduce the risk of passing it to partners
What about pregnancy?
- Herpes can be dangerous for newborn babies
- If you have active sores at delivery, a caesarean is usually recommended
- Tell your midwife or doctor if you or your partner have herpes
12. References
- BASHH Guidelines on the Management of Genital Herpes. 2014.
- CDC Sexually Transmitted Infections Treatment Guidelines. 2021.
- Clinical Effectiveness Group. Genital Herpes IUSTI Guidelines. 2017.