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, immunosuppressed, post transplant, HIV)

Clinical Features

• Prodrome: Headache, malaise, photophobia
• Antecedent pruritis, 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
• Herpes Zoster Ophthalmicus
• Herpes Zoster Oticus (Ramsay Hunt Syndrome)

Herpes Zoster

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

• Pain
  • PO narcotics
• Antiviral
  • Reduces risk/duration of postherpetic neuralgia
  • Immunocompetent patients:
    • Give acyclovir if <72hr of onset of rash or >72hr if new vesicles present/developing
    • Acyclovir 800mg PO 5x/day x 7d
  • Immunosuppressed patients:
    • Give antiviral therapy at any stage of onset of rash
    • Acyclovir 10 mg/kg IV q8h OR 800mg PO 5x/day x 7d or foscarnet for acyclovir-resistant VZV, disseminated zoster, CNS involvement, ophthalmic involvement, advanced AIDS, recent transplant
• Steroids not shown to be beneficial

Disposition

• Admit for 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
• Herpes Viruses

Source

• Tintinalli, Rosen's, eMedicine, Epocrates
• Images provided by University of Iowa Dept. of Dermatology