Herpes zoster

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Background

  • Caused by varicella zoster virus (VZV) causing Varicella (chicken pox) and later zoster (shingles)
  • Virus is dormant in dorsal root ganglion and reactivates causing characteristic rash 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 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.