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)

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 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

Differential Diagnosis

• Smallpox
• Cellulitis
• Contact Dermatitis
• Measles

Varicella zoster virus

• Varicella (Chickenpox)
• Herpes zoster (Shingles)
  • Herpes zoster ophthalmicus
  • Herpes zoster oticus (Ramsay Hunt syndrome)

Diagnostic Evaluation

Workup

• Generally a clinical diagnosis
• May consider viral Culture, antigen, PCR of vesicle fluid

Evaluation

• Confirm that the patient does not have:
  • Herpes zoster ophthalmicus
  • Herpes zoster oticus (Ramsay Hunt syndrome)
• 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:
  • Pneumonitis
  • Hepatitis
  • Encephalitis

Management

Analgesia

• Analgesia is very important and should be prescribed along with an antiviral
• Consider NSAIDS, oral opioids, or gabapentin

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
• 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 < 10 ml/min)

Immunosuppressed patients:

• Antiviral therapy should be given regardless of the time 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, or recent transplant
• Isolation precautions
  • Disseminated zoster requires airborne precautions

Glucocorticoids

• Steroids not shown to be beneficial

Disposition

• Admit for disseminated VZ, CNS involvement, severely immunosupressed
• Healing of lesions may take 4 or more weeks

Complications

• Postherpetic Neuralgia (risk increases with age)
• Cellulitis
• Impetigo
• Necrotizing Fasciitis

See Also

• Herpes zoster ophthalmicus
• Herpes zoster oticus (Ramsay Hunt syndrome)
• Generalized rashes