HERPES ZOSTER (SHINGLES)

 

Etiology:

  1. Varicella-Zoster virus reactivation. 

S & S:

  1. Pain, paresthesia precede the eruption of lesions by 3 -7days.
  2. Constitutional signs are rare = 5 -10%. Regional adenopathy is often present.
  3. Skin lesions start as papules  vesicles  pustules  crust.  They evolve over 7-10 days.  The lesions occur in 1 to 3 contiguous dermatomes (if dermatomes are not contiguous then considered disseminated zoster).
     
  4. HZ lesions on external ear and/or on timpanic membrane and involvement of facial nerve of the same side represent Ramsay-Hunt Syndrome.
     
  5. Involvement of trigeminal nerve (V1) can cause HZ ophtalmicus. This may be preceded by vesicular lesion on tip of the nose  which is indicative of involvement of the nasociliary branch of V1. Ophthalmic HZ can cause conjunctivitis, keratitis (painful), and uveitis and can lead to scarring.
     
  6. The diagnosis of disseminated HZ is made if more than 20 vesicles are present outside of the primary and immediately adjacent dermatomes. This is most often seen in immunocompromised patients (lymphoma, AIDS, chemotherapy) and the elderly. 10% of patients with disseminated zoster will have visceral involvement (lungs, liver, brain).
     
  7. 7. Post-herpetic neuralgia is diagnosed when pain at the site of prior zoster has persisted for over 1 month.

DX:

  1. History and physical.
     
  2. Tzanck smear ( positive in 70%  of early cases; look for multinucleated giant cells).
     
  3. Culture of an intact vesicle for VZV.
     
  4. Serology can be used to document acute or prior exposure to VZV.

Treatment:

  1. Immunocompetent/Uncomplicated:
     
  2. Acyclovir 800 mg 5/day x 10 days
                            or
    Valacyclovir 1 g po tid for 7 days     
                            or
     Famcyclovir 500 mg po tid for 7 days.
     
    Therapy started within 48 -72 hrs. of initial lesion, shortens disease course and the duration  of postherpetic neuralgia. Patients should be asked about current or prior kidney disease, and if there is any concern regarding their renal  function, BUN/Cr should be evaluated.
     
  3. In case of suspected ophthalmic HZ, ophthalmologic consult is mandated.  Acyclovir 800 mg 5/d  x 10 days may prevent ophthalmic complication when started early.  Ophthalmic antibiotics (drops and ointment) are also used to prevent suprainfection.
     
  4. Disseminated HZ/Severe infection.  Admission warranted. Acyclovir 10 mg/kg IV x 7d (given over one hour q8h)
     
  5. Both contact as well as respiratory isolation of  hospitalized patients with zoster is required to protect other immunocompromised patients in the hospital from possible exposure.  Pts who are notadmitted should be given few days off  from work/school (until the lesions crust) in order not to expose them to other people who never had chickenpox and are not immunized.

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