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)
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
- 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
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[1]
- 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
Not Benificial
- 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