Pathophysiology & Transmission
Viral Characteristics
- Caused by Herpes Simplex Virus (HSV-1 or HSV-2)
- Following primary infection, virus becomes latent in local sensory ganglia
- Recurrent episodes due to reactivation after latent period
- Can cause symptomatic lesions or asymptomatic viral shedding
Transmission Routes
Primary Transmission
- Acquired at mucosal surfaces or skin breaks
- Direct contact with infected secretions
- HSV-2: vaginal or anal intercourse
- HSV-1: orogenital intercourse
Other Routes
- Contact with lesions at other sites (eyes, fingers)
- Non-mucosal surfaces (herpetic whitlow)
- Autoinoculation to adjacent skin
- Vertical transmission to neonate
Infectious Periods
- Highest risk: when lesions present (vesicles, ulcers)
- Lower risk: asymptomatic viral shedding
- Shedding can occur without visible lesions
- Transmission possible throughout infection
Clinical Features
First Episode
Lesion Characteristics
- Multiple painful blisters
- Quickly burst to form erosions/ulcers
- Location: external genitalia, cervix, rectum, thighs, buttocks
- Usually bilateral distribution
- Develop 4-7 days after exposure
Systemic Symptoms
- 50% report systemic symptoms:
- Headache, fever, malaise
- Dysuria
- Tender inguinal lymphadenopathy
- Duration: up to 20 days
Additional Features
- Vaginal or urethral discharge
- Local oedema
- Tingling/neuropathic pain in genital area
- Pain in lower back, buttocks, legs
- Often more severe than recurrent episodes
Recurrent Genital Herpes
Key Features
- Occur in same anatomical area
- Prodromal symptoms: tingling/burning up to 48 hours before lesions
- Less severe than initial episodes
- Duration: 6-48 hours for symptoms
- Lesions crust and heal in ~10 days
- Systemic symptoms less common
Diagnosis & Differential Diagnosis
Diagnostic Approach
- Refer to GUM specialist for confirmation
- Swab from base of lesion (pop blister if necessary)
- Tests: viral culture or PCR (depending on local arrangements)
- Virus type identification important for prognosis/counseling
Differential Diagnosis
STI Ulcers
- Syphilis: single, non-tender ulcer
- Chancroid: single deep, painful ulcer
- LGV: single/few ulcers + unilateral lymphadenopathy
- Granuloma inguinale: painless, vascular ulcers
Other Infections
- Herpes zoster (dermatomal distribution)
- Scabies (burrows, intense itching)
- Candida (erythema, satellite lesions)
- Bacterial superinfection
Non-infectious Causes
- Aphthous ulcers (fewer, larger lesions)
- Skin disorders: dermatitis, psoriasis
- Folliculitis, lichen sclerosus
- Behçet's syndrome, Crohn's disease
- Malignancy
- Fixed drug eruptions
Management
Referral Recommendation
Ideally refer all suspected cases to GUM specialist for:
- Accurate diagnosis
- Comprehensive treatment
- STI screening
- Counselling and education
- Appropriate follow-up
First Episode Treatment
| Medication | Dosage | Duration | Notes |
|---|---|---|---|
| Aciclovir | 200 mg five times daily | 5-10 days | Start within 5 days of symptom onset |
| Valaciclovir | 500 mg twice daily | 5-10 days | Alternative with better bioavailability |
| Famciclovir | 250 mg three times daily | 5-10 days | Alternative option |
Self-care Measures
Hygiene & Comfort
- Clean with plain or salt water
- Apply vaseline or topical anaesthetic
- Increase fluid intake for dilute urine
- Urinate in bath or with water flowing
Lifestyle Measures
- Avoid tight clothing
- Take adequate pain relief
- Avoid sharing towels/flannels
- Abstain from sexual contact until cleared
Recurrent Episode Management
Treatment Strategies
Episodic Treatment
- For: <6 attacks per year
- Aciclovir: 200mg 5x/day for 5 days
- Consider self-initiated treatment
- Start early in next attack
- Shorter course than first episode
Suppressive Treatment
- For: ≥6 attacks per year
- Or: psychological distress
- Or: affects social life
- Aciclovir: 400mg twice daily
- Duration: 6-12 months initially
- Review annually for continuation
Antiviral Options for Recurrences
| Regimen | Episodic Therapy | Suppressive Therapy |
|---|---|---|
| Aciclovir | 200mg 5x/day × 5 days | 400mg twice daily |
| Valaciclovir | 500mg twice daily × 5 days | 500mg once daily |
| Famciclovir | 125mg twice daily × 5 days | 250mg twice daily |
Complications
Local Complications
- Superinfection with Candida or Streptococci
- Autoinoculation to fingers and adjacent skin
- Secondary bacterial infection
- Scarring and pigment changes
Neurological Complications
- Autonomic neuropathy causing urinary retention
- Aseptic meningitis during primary infection
- Recurrent meningitis over months/years
- Radiculopathy
Special Populations
- Neonatal HSV: highest risk if maternal acquisition in third trimester
- Immunocompromised: more severe, prolonged episodes
- Pregnancy: risk of vertical transmission
- HIV co-infection: more frequent recurrences
Prevention & Counseling
Key Counseling Points
- Lifelong infection with recurrent episodes
- Transmission risk even without symptoms
- Condoms reduce but don't eliminate risk
- Avoid sexual contact during prodrome/lesions
- Inform partners about infection status
- Suppressive therapy reduces transmission risk