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
Differential Diagnosis
- Smallpox
- Cellulitis
- Contact Dermatitis
- Measles
Varicella zoster virus
- Varicella (Chickenpox)
- Herpes zoster (Shingles)
- Herpes zoster ophthalmicus
- Herpes zoster oticus (Ramsay Hunt syndrome)
Diagnosis
Workup
- Clinical diagnosis in most cases
- 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
Treatment
- Pain
- PO narcotics
- Antiviral
- Reduces risk/duration of postherpetic neuralgia
- Immunocompetent patients:
- 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
Not Beneficial
- Steroids not shown to be beneficial
Disposition
- Admit for disseminated VZ, CNS involvement, severely immunosupressed
- Healing of lesions may take 4 or more weeks[2]
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