Acute herpes zoster

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, those on immunosupressants/post transplant, HIV)

Clinical Features

• Prodrome: Headache, malaise, photophobia
• Antecedent pruritis, paresthesia, pain to dermatome 2-3 days prior to rash
• Maculopapular rash progresses to vesicles (and can coalesce to bullae) in dermatomal distribution lasting 10-15 days
• Does not cross midline
• Typically affects chest/face
• Herpes Zoster Opthalmicus- See Herpes Zoster Ophthalmicus
• Herpes Zoster Oticus (Ramsay Hunt Syndrome)

Work-Up

Further evaluation if disseminated VZV

• Immunocompromised
• If more than 3 or more dermatomes affected
• If young, previously healthy adult-may be initial presentation with HIV
• Further evaluation for pneumonitis, hepatitis, encephalitis as clinically indicated
• Atypical illness/severe disease
  • Viral Culture, antigen, PCR of vesicle fluid

DDx

• Smallpox
• Cellulitis
• Contact Dermatitis
• Measles

Treatment

• PO narcotics for pain, can consider corticosteroids to help with acute pain if no contraindication in elderly
• Reduce risk/duration of postherpetic neuralgia w/ antivirals
  • Immunocompetent patients:
    • Give Acyclovir if < 72 hrs of onset of rash or at > 72 hrs if new vesicles present/developing
    • Acyclovir 800mg PO 5x/day x 7 days
  • Immunosupressed patients:
    • Give Acyclovir at any stage of onset of rash
    • Acyclovir 10 mg/kg IV q8h x 7 days or Foscarnet (If acyclovir-resistant VZV) if disseminated zoster, CNS involvement, ophthalmic involvement, or severely immunosupressed (advanced AIDS, recent transplant)
    • Otherwise Acyclovir PO 800mg PO 5x/day x 7days
      
  • Herpes Zoster opthalmicus
    • Ophthalmology consult and Acyclovir/Valacyclovir

Disposition

Admit if disseminated VZ, CNS involvement, severely immunosupressed

Complications

Postherpetic neuralgia (risk increases with age), cellulitis, impetigo, necrotizing fasciitis

Prevention

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

See Also

Herpes Zoster Ophthalmicus

Source

Tintinalli, Rosen's, eMedicine, Epocrates