Synopsis
Recognise primary and recurrent genital herpes, confirm infection from fresh lesions, relieve pain, use time-sensitive antivirals and manage pregnancy and neonatal exposure safely.
- Primary genital herpes may cause multiple painful vesicles or shallow ulcers, dysuria, tender nodes, fever and profound malaise.
- Recurrent disease is usually shorter and milder, often preceded by tingling or burning in a similar dermatomal area.
- Swab the base of a fresh vesicle or ulcer for HSV-1 and HSV-2 NAAT; blood serology does not confirm the cause of an active ulcer.
- Start oral antiviral treatment within five days of a first episode or while new lesions are still appearing; do not wait for the swab result.
- Give aciclovir 400 mg orally three times daily for five days for an uncomplicated first episode, extending when healing is incomplete.
- Use saline bathing, regular analgesia, topical lidocaine and measures that reduce urinary pain alongside antivirals.
- Transmission can occur during asymptomatic shedding; avoid sex during prodrome or lesions and discuss condoms and disclosure without stigma.
- Pregnancy timing and whether infection is new or recurrent determine delivery and neonatal management.
Key red flags
Severe pain with inability to pass urine may require admission, analgesia and temporary catheterisation.
Headache, photophobia, neck stiffness, altered behaviour, weakness or sacral sensory symptoms suggests HSV neurological involvement.
Widespread lesions, hepatitis, pneumonitis or shock can occur in pregnancy or major immunosuppression.
Any suspected neonatal herpes with vesicles, lethargy, poor feeding, seizures or sepsis requires immediate intravenous aciclovir.
A first genital episode late in pregnancy has high neonatal-transmission risk and needs same-day specialist maternity planning.
Persistent, hypertrophic or treatment-resistant ulcers in advanced HIV require culture, resistance and alternative-diagnosis assessment.
Urinary retention, constipation, perineal sensory change or leg symptoms during herpes suggests autonomic and nerve-root involvement.
Widespread vesicles with hepatitis, pneumonitis, encephalopathy or sepsis is rare but life threatening in pregnancy or immunosuppression.
A neonate with vesicles, conjunctivitis, poor feeding, fever, hypothermia, seizures or unexplained liver injury needs emergency treatment.
Investigation priorities
Confirm herpes and distinguish HSV-1 from HSV-2 using material from a fresh vesicle or ulcer base.
Management branches
Painful genital vesicles or ulcers began within five days or new lesions continue to appear.
- Swab a fresh lesion for typed HSV NAAT and obtain syphilis, HIV and site-specific STI testing.
- Start aciclovir 400 mg orally three times daily for five days without waiting for the result.
- Provide regular analgesia, saline bathing, topical lidocaine and advice to pass urine in water when severe dysuria occurs.
- Review healing near day five and extend antiviral therapy if new lesions continue or ulcers remain substantially unhealed.