Herpes zoster

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Background

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

Prevention

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

Clinical Features

  • 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

Differential Diagnosis

Vesiculobullous rashes

Febrile

Afebrile

Varicella zoster virus

Evaluation

Workup

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

Evaluation

  • Confirm that the patient does not have:
  • Consider further evaluation for immunocompromized state (may be initial presentation of HIV) if:
    • Disseminated
    • If more than 3 or more dermatomes affected
    • Atypical illness/severe disease
  • In immunocompromized patients consider further evaluation for:

Management

Analgesia

  • Analgesia is very important and should be prescribed along with an antiviral
  • Consider Lidocaine patch, NSAIDS, oral opioids, or gabapentin
  • Diphenhydramine and ranitidine for itch/pain

Antiviral

  • Reduces risk/duration of postherpetic neuralgia with dosing based on immune status and time course of disease

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

Glucocorticoids

  • Steroids not shown to be beneficial[2]

Disposition

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

Complications

See Also

References

  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.
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