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InfectionVZV reactivationICD-10 B02.x

Herpes zoster

Shingles · VZV reactivation

Herpes zoster (shingles) is dermatomal reactivation of latent varicella-zoster virus (VZV) in cranial / dorsal-root ganglia. It is far more common in adults >50, the immunosuppressed, including patients on chemotherapy, biologics, JAK inhibitors and immune-checkpoint inhibitors. UK skin-oncology relevance is fourfold: (1) ICI-related reactivation, (2) disseminated zoster in advanced disease, (3) post-herpetic neuralgia as a chronic morbidity, and (4) routine vaccination (Shingrix) for at-risk patients per UK Green Book.

CurrentLast reviewed 16 May 2026
Clinical image of Herpes zoster (shingles)
Herpes zoster (shingles). Image sourced from DermNet New Zealand. Used under CC BY-NC-ND 4.0. No endorsement implied.

Biology and risk

  • Primary infection (chickenpox) establishes latent VZV in cranial / dorsal-root ganglia.
  • Reactivation occurs with declining cell-mediated immunity; lifetime risk ~30%.
  • Risk factors: age >50, immunosuppression (HIV, malignancy, chemotherapy, biologics, JAK inhibitors, ICI, stem-cell transplant), diabetes, stress.

Clinical features

  • Prodrome 2-3 days of pain, burning, itch, paraesthesia in the affected dermatome.
  • Eruption: grouped erythematous papules → vesicles → pustules → crusts in 7-10 days, in a unilateral dermatomal distribution.
  • Commonest dermatomes: thoracic (T3-L2), trigeminal V1 (herpes zoster ophthalmicus — ophthalmology emergency).
  • Special variants:
    • Herpes zoster ophthalmicus — V1 distribution; Hutchinson sign (nasociliary nerve, tip of nose) predicts ocular involvement.
    • Ramsay Hunt syndrome (zoster oticus) — facial nerve palsy + vesicles in external auditory canal / tympanic membrane + hearing loss.
    • Disseminated zoster — >20 vesicles outside the primary dermatome; immunosuppressed.
    • Multidermatomal zoster — adjacent dermatomes; often immunosuppression.
  • Complications:
    • Post-herpetic neuralgia (~10-20% >50 y).
    • Secondary bacterial infection.
    • Encephalitis, myelitis, stroke (VZV vasculopathy).
    • Scarring, post-inflammatory pigment change.

Investigations

  • Clinical diagnosis in classical presentation.
  • VZV PCR from vesicle base swab — most sensitive.
  • Tzanck smear (multinucleated giant cells; non-specific HSV/VZV).
  • Direct fluorescent antibody.
  • HIV testing in young / atypical / disseminated cases.
  • If trigeminal V1: urgent ophthalmology referral.

Differentials

  • Herpes simplex (zosteriform) — recurrent at same site.
  • Contact dermatitis, irritant linear eruption.
  • Cellulitis, erysipelas.
  • Linear cutaneous mastocytosis, urticarial vasculitis.
  • Bullous pemphigoid (localised), dermatitis herpetiformis.
  • Disseminated zoster vs varicella vs widespread HSV.

Management

  • Antiviral within 72 hours of rash onset reduces pain duration and PHN risk:
    • Aciclovir 800 mg PO 5× daily for 7 days.
    • Valaciclovir 1 g PO TDS for 7 days.
    • Famciclovir 500 mg PO TDS for 7 days.
  • IV aciclovir 10 mg/kg TDS in immunosuppressed, disseminated, ophthalmic, CNS involvement.
  • Analgesia: paracetamol, NSAIDs; opioid step-up; gabapentin / pregabalin / amitriptyline / nortriptyline for neuropathic pain.
  • Topical: bland emollient, calamine; capsaicin / lidocaine 5% plaster for PHN.
  • Ophthalmology referral for HZ ophthalmicus; ENT for Ramsay Hunt.
  • Vaccination:
    • Shingrix (adjuvanted recombinant subunit VZV) — UK Green Book offers from age 65 in the routine programme, and from age 18 for people who are severely immunosuppressed; two-dose schedule.
    • Zostavax (live-attenuated) being phased out in UK.
  • Skin-oncology specifics:
    • ICI-related zoster — treat antiviral; usually do not stop ICI for typical zoster (G1-2); G3+ disseminated → hold ICI, oncology / ID review.
    • Chemotherapy / biologics: aciclovir prophylaxis sometimes given (allogeneic HSCT).

References

  1. Cohen JI. Clinical practice: herpes zoster. N Engl J Med. 2013;369:255-263.
  2. UK Health Security Agency. Immunisation against infectious disease (the Green Book): Chapter 28A — Shingles. London: UKHSA; last updated 19 August 2025.
  3. NICE CKS. Shingles. London: NICE; accessed 18 May 2026.
  4. Lal H et al. Efficacy of an adjuvanted herpes zoster subunit vaccine in older adults. N Engl J Med. 2015;372:2087-2096.

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