REBEL Core Cast 78.0 – Herpes Zoster

Take Home Points

  • Classically, herpes zoster will present with rash and pain in a dermatomal distribution
  • Immunocompromised patients are at greater risk for significant complications of zoster, including visceral dissemination and zoster ophthalmicus
  • Appropriate therapy includes antiviral therapy within 72 hours of onset of symptoms and analgesia for acute neuritis
  • Disseminated zoster and zoster ophthalmicus threatening sight should be treated with IV antivirals

REBEL Core Cast 78.0 – Herpes Zoster

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Definition: Reactivation of the varicella zoster virus (VZV) within sensory ganglia  

  • Simple herpes zoster: lesions in single dermatome without crossing the midline
  • Herpes zoster ophthalmicus: Reactivation of VZV in CN V1 (ophthalmic division). 
    • Presents with dermatomal distribution on the face, roughly 50% of cases involve the eye (Liesegang 2008)
  • Disseminated Zoster
    • Rash in multiple dermatomes
    • Rash crosses the midline

Epidemiology

  • Affects nearly 1,000,000 people annually in U.S (Yawn 2007)
  • > 30% of the U.S population will experience zoster (Harpaz 2008)
  • 50% of people who live to age 85 will have an episode of Herpes zoster (Schmader 2001)
  • Rates of herpes zoster have been increasing 
    • 1949: 0.76 per 1000 person years (Kawai 2016)
    • Estimates as high as 5.2 episodes per 1000 person years in 2007 (Rimland 2010)
  • More prevalent in females, incidence increases with age in both sexes (Kawai 2016)
  • Risk Factors 
    • Age 
    • Immunocompromised status – including transplant patients, HIV infected patients, and those with underlying malignancy
    • Physical Trauma 
    • Chronic lung or kidney disease 

Pathophysiology

  • Reactivation of latent varicella-zoster virus (VZV) in dorsal root ganglia 
  • Reactivation of VZV results in inflammation of dorsal spinal ganglia, resulting in dermatomal distribution of pain and vesicular rash 

Presentation

  • History
    • Previous diagnosis of chickenpox
    • Dermatomal pain and pruritus up to 5 days prior to the development of skin lesions 
          • Pain quality may be variable in presentation – aching, burning, or stab-like 
  • Physical Exam 
    • Rash in dermatomal pattern, typically on trunk
    • Rash is erythematous, typically with a macular base and clear vesicles that progress to scab and crust formation.
      • Formation of scabs takes 10-12 days
      • Heals within 2-4 weeks
        • Other physical exam findings such as lung crackles, hepatomegaly, and neurologic deficits may indicate visceral involvement following cutaneous dissemination

Differential

  • Primary varicella infection
  • Herpes simplex infection
  • Burn
  • Contact Dermatitis
  • Insect bites
  • Impetigo
  • Dermatitis herpetiformis

Management of herpes zoster

  • Initiation of antiviral therapy should occur within 72 hours of onset
    • Antiviral therapy
      • Increased rate of healing of skin lesions
      • May reduce acute neuritis
      • May help prevent postherpetic neuralgia
    • If new lesions continue to appear antiviral therapy is recommended, even past 72 hours from onset 
    • Choice of antiviral therapy 
      • Valaciclovir 1000mg PO Q8 x 7 days
      • Famciclovir 500mg PO Q8 x 7 days
      • Acyclovir 800mg PO five times daily x 7 days
    • Intravenous therapy indicated for:
      • Disseminated zoster
      • Zoster ophthalmicus with ocular involvement
      • Inability to tolerate oral medications
  • Analgesia may be needed for the management of acute neuritis
    • First line choices include NSAIDs and acetaminophen
    • For moderate to severe pain, opioid analgesic may be needed
  • Treatment for immunocompromised patient
    • Should be treated regardless of time from onset of lesions
    • If disseminated or involves more than one dermatome IV acyclovir should be used for treatment
  • Patients with active lesions should be counseled to avoid patients who are immunocompromised and pregnant women to avoid transmission

Complications

  • Postherpetic neuralgia – most common complication and occurs in up to 15% of patients. Incidence increases with age
  • Bacterial skin infection – secondary infection due to open skin lesion
  • Ocular complications, including keratitis and vision loss
  • Disseminated herpes zoster – herpes zoster that is not confined to dorsal root ganglia
    • More common in immunocompromised patients
    • Cutaneous dissemination may progress to visceral organ involvement, resulting in pneumonia, hepatitis, or encephalitis. Visceral dissemination may be life threatening

Disposition

  • Most patients are suitable for outpatient management with oral antiviral agents and analgesia
  • Indications for admission:
    • Disseminated zoster
    • Immunosuppressed state (HIV, diabetes, chemotherapy)
    • Zoster requiring IV antiviral therapy or analgesic control

Take Home Points

  • Classically, herpes zoster will present with rash and pain in a dermatomal distribution
  • Immunocompromised patients are at greater risk for significant complications of zoster, including visceral dissemination and zoster ophthalmicus
  • Appropriate therapy includes antiviral therapy within 72 hours of onset of symptoms and analgesia for acute neuritis
  • Disseminated zoster and zoster ophthalmicus threatening sight should be treated with IV antivirals

Read More

References

  1. Liesegang TJ. Herpes zoster ophthalmicus natural history, risk factors, clinical presentation, and morbidity. Ophthalmology. 2008 Feb;115(2 Suppl):S3-12. PMID: 18243930 
  2. Yawn BP et al. A population-based study of the incidence and complication rates of herpes zoster before zoster vaccine introduction. Mayo Clin Proc 2007; 82(11): 1341-9. PMID: 17976353
  3. Harpaz R et al. Prevention of herpes zoster: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2008 Jun 6;57(RR-5):1-30; quiz CE2-4. PMID: 18528318
  4. Schmader K. Herpes zoster in older adults. Clin Infect Dis. 2001 May 15;32(10):1481-6. PMID: 11317250
  5. Kawai et al. Increasing incidence of herpes zoster over a 60-year period from a population-based study. Clin Infect Dis. 2016 Jul 15;63(2):221-6. PMID: 27161774
  6. Rimland et al. Increasing incidence of herpes zoster among Veterans. Clin Infect Dis. 2010 Apr 1;50(7):1000-5. PMID: 20178416

Post Created By: Alex Estrella, MD

Post Peer Reviewed By: Salim R. Rezaie, MD (Twitter: @srrezaie)

Cite this article as: Anand Swaminathan, "REBEL Core Cast 78.0 – Herpes Zoster", REBEL EM blog, April 6, 2022. Available at: https://rebelem.com/rebel-core-cast-78-0-herpes-zoster/.
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Anand Swaminathan

Clinical Assistant Professor of Emergency Medicine at St. Joe's Regional Medical Center (Paterson, NJ)
REBEL EM Associate Editor and Author

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