Painful vesicular rash in a dermatome
Treat (<72 h): Valacyclovir 1 g PO TID ×7 d (or acyclovir/famciclovir); still warranted >72 h if new lesions, ophthalmicus, or immunocompromised
Ophthalmic branch / eye → urgent ophthalmology
Prevent: recombinant zoster vaccine ≥50 y (and ≥19 y if immunocompromised, ACIP); gabapentin for postherpetic neuralgia
Order set
- Clinical diagnosis
- Antiviral <72 h
- Analgesia
- Assess dermatome/eye
Criteria
AdmitDisseminated/ophthalmic/immunocompromised
DischargeAntivirals + analgesia, eye reviewed, PHN plan
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
- Ophthalmic involvement
- Disseminated zoster (immunocompromised)
- Ramsay Hunt
Differentials
- HSV
- Contact dermatitis
- Cellulitis
Common mistakes
- Delaying antivirals
- Missing eye involvement
Disposition & follow-up
Antivirals + analgesia; ophthalmology if eye; vaccinate later.
Discharge package
MedicationsAntivirals + analgesia; neuropathic agent for PHN
Follow-upOphthalmology if eye involved
VaccinationRecombinant zoster vaccine later
Warning symptomsEye involvement, spreading rash, severe pain
💊 Treatment detail — doses & preparation
Valaciclovirantiviral
Dose1 g PO TDS ×7 d (zoster; start <72 h of rash)
Preparation500/1000 mg tablets with water
MonitorRenal function, hydration; longer if ophthalmicus/immunocompromised
Gabapentinneuropathic analgesia
Dose300 mg OD day 1 → BD day 2 → TDS; titrate to 600–1200 mg TDS (post-herpetic neuralgia)
Preparation100/300/400 mg capsules; taper to stop
MonitorRenal dosing, sedation, oedema
📖 CDC / IDSA ZosterReviewed July 2026