Herpes zoster

(Redirected from Zoster)


  • Also known as shingles
  • Caused by varicella zoster virus (VZV; also known as Human Herpes Virus 3) causing Varicella (chicken pox) and later zoster (shingles)
  • Virus is dormant in dorsal root ganglion and reactivates causing characteristic vesiculopapular rash in dermatomal distribution
  • Occurs once immunity to virus declines (elderly, immunosuppressed, post transplant, HIV)


  • Patient is contagious until lesions are crusted over
  • Consider varicella-zoster immunoglobulin to immunosupressed, pregnant, neonate contacts
  • Zoster vaccination if >60

Herpes Virus Types

Clinical Features

Herpes Zoster
Herpes Zoster
  • Prodrome: Headache, malaise, photophobia
  • Antecedent pruritus, paresthesia, pain to dermatome 2-3 days prior to rash
  • Maculopapular rash (see below) progresses to vesicles, may coalesce to bullae, in dermatomal distribution lasting 10-15 days
  • Does not cross midline
  • Typically affects chest/face
  • Lumbar and sacral dermatomes may display skin sparing between the feet and groin
  • V3 involvement can present initially as dental pain
Herpes Zoster.jpg

Differential Diagnosis

Vesiculobullous rashes



Varicella zoster virus



  • Generally a clinical diagnosis
  • May consider viral Culture, antigen, PCR of vesicle fluid


  • Confirm that the patient does not have:
  • Consider further evaluation for immunocompromized state (may be initial presentation of HIV) if:
    • Disseminated
      • For skin disseminated is 3 or more dermatomes affected.
      • Can also disseminate to other organs including liver, lung, and brain.
    • Atypical illness/severe disease
  • In immunocompromised patients consider further evaluation for:




  • Reduces risk/duration of postherpetic neuralgia with dosing based on immune status and time course of disease
  • Not effective in treating postherpetic neuralgia once it has developed

Immunocompetent patients:

  • Acyclovir 800mg PO 5x/day x 7d if <72hr of onset of rash or >72hr if new vesicles present/developing[1]
  • Valacyclovir (can also be given but is generally more expensive than acyclovir)
    • 1g PO q8hrs (CrCl normal)
    • 1g PO q12hrs (CrCl 30-49 mL/min)
    • 1g PO q24hrs (CrCl 10-29 mL/min(
    • 500mg q24hrs PO (CrCl < 10ml/min)

Immunosuppressed patients:

  • Antiviral therapy should be given regardless of the time of onset of rash
  • Acyclovir 10mg/kg IV q8h OR 800mg PO 5x/day x 7d or Foscarnet for acyclovir-resistant VZV, disseminated zoster, CNS involvement, ophthalmic involvement, advanced AIDS, or recent transplant
  • Isolation precautions
    • Disseminated zoster requires airborne precautions


  • Steroids not shown to be beneficial[2]


  • Admit for disseminated VZ, CNS involvement, severely immunosuppressed
  • Healing of lesions may take 4 or more weeks[3]


See Also


  1. Cohen, J. Herpes Zoster. N Engl J Med 2013; 369:255-263. DOI: 10.1056/NEJMcp1302674
  2. He L, Zhang D, Zhou M, Zhu C. Corticosteroids for preventing postherpetic neuralgia. Cochrane Database Syst Rev. 2008.
  3. Sampathkumar P, et al. Herpes zoster (shingles) and postherpetic neuralgia. Mayo Clin Proc. 2009; 84(3):274–280.