16th July 2026

Herpes Zoster Virus (HZV)

Herpes zoster (HZV; shingles) results from reactivation of latent varicella-zoster virus (VZV) — the agent responsible for chickenpox. Following resolution of primary infection, VZV remains dormant in dorsal root or cranial nerve ganglia, reactivating years later, particularly in the elderly or immunocompromised.

It presents as a painful, unilateral vesicular rash distributed along a single dermatome. Prodromal burning, tingling, or hyperesthesia often precedes the rash by 1–3 days. Common sites include thoracic dermatomes and the trigeminal distribution.

Complications include:

• Postherpetic neuralgia (PHN) — persistent neuropathic pain lasting >3 months
• Herpes zoster ophthalmicus — involving the V1 branch; requires urgent ophthalmology referral
• Disseminated zoster in immunocompromised individuals

Diagnosis

Diagnosis is typically clinical. Consider PCR of vesicular fluid or skin biopsy in atypical presentations.

Management

• Antiviral therapy (start within 72 hours of rash onset):
  • Aciclovir 800 mg 5 times daily for 7 days
  • Alternatives: valaciclovir or famciclovir (better oral bioavailability)
• Analgesia:
  • Paracetamol/NSAIDs
  • Neuropathic agents for PHN (e.g. gabapentin, amitriptyline)
• Zoster vaccine is recommended for adults >50 years and those at increased risk