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

• Emergency Medicine Ireland: Tasty Morsels of EM 073: FRCEM Varicella
• Life in the Fast Lane: Herpes zoster ophthalmicus
• Up to Date: Treatment of herpes zoster in the immunocompetent host
• Concise Review for Clinicians – Herpes Zoster (Shingles) and Postherpetic Neuralgia
• Marco CA: Dermatologic Presentations, in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2014, (Ch) 110: p 1430-1454.

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)