Rosen & Barkin's 5-Minute Emergency Medicine Consult (342 page)

• 054.9 Herpes simplex without mention of complication
  
• 054.41 Herpes simplex dermatitis of eyelid
  
• 054.79 Herpes simplex with other specified complications
  

BASICS

• Commonly known as shingles
  
• Characterized by unilateral eruption of painful vesicles along a single dermatome
  
• Disseminates rarely in normal hosts and frequently in immunocompromised hosts
  
• Most common in patients with decreased cell-mediated immunity:
  
  • Older than 50 yr of age
    
  • Neoplastic diseases
    
  • Immunosuppressive drugs
    

• Caused by varicella zoster virus (VZV), a DNA virus in the Herpesviridae family
  
• Reactivation of dormant virus in dorsal root ganglia
  
• Mostly in individuals who previously had chickenpox and very rarely in vaccinated individuals
  

Zoster in pregnancy is not associated with increased risk of congenital varicella syndrome

May occur in childhood, most commonly when primary varicella occurred in utero or in the first 6 mo of life

DIAGNOSIS

• Dermatomal zoster
  
  • Prodrome of pain and paresthesias in 75% of patients
    
  • Pain may be sharp, dull, tingling, burning, or intense pruritus
    
  • Classical rash is grouped vesicles on erythematous base
    
  • Progress to scab and crust formation over 7–10 days; crusts fall off in 2–3 wk
    
  • Most common nerve distributions are thoracic and lumbar, followed by trigeminal and cervical
    
• Zoster sine herpete
  
  • Syndrome occurs without the rash
    
• Herpes zoster ophthalmicus (HZO)
  
  • Involvement of ophthalmic division of trigeminal nerve
    
  • Hutchinson sign – lesion on tip of nose
    
  • May cause punctate keratitis or corneal pseudodendrites (elevated mucous plaques, less ulcerative and less fluorescein uptake than HSV dendrites)
    
• Ramsay Hunt syndrome
  
  • From VII and VIII cranial nerve involvement
    
  • Lesions in the external auditory canal, peripheral facial palsy, vertigo and anesthesia of anterior 2/3 of hemitongue
    
  • Progress to scab and crust formation over 7–10 days; crusts fall off in 2–3 wk
    
  • Most common nerve distributions are thoracic and lumbar, followed by trigeminal and cervical
    
• Disseminated disease may cause:
  
  • Myelitis
    
  • Meningoencephalitis
    
  • Peripheral neuropathy
    
  • Hepatitis
    
  • Pneumonitis
    
• Postherpetic neuralgia (PHN) is a complication of zoster:
  
  • Described as pain that persists at site of zoster lesions for >3 mo after cutaneous disease has healed
    
  • 10–70% of patients will have pain after resolution of lesions
    
  • Incidence increases with age older than 50 yr, severe rash, and severe pain
    

• Clinical presentation is sufficient for diagnosis in most patients
  
• Labs may aid diagnosis in patients with atypical rash or disseminated disease
  

• Tzanck Smear
  
  • Cheap and easy
    
  • Scrape base of unroofed vesicle
    
  • Multinucleated giant cells on Giemsa stain
    
  • Cannot distinguish VZV from HSV
    
  • Low sensitivity
    
• PCR is the preferred method
  
  • From vesicle scraping, blood, CSF or BAL
    
  • Can distinguish between HSV and VZV
    
  • More sensitive and specific
    
• Serology (IgM/IgG)
  
  • More difficult to interpret
    
  • Less sensitive/specific
    
• Viral culture
  
  • Slow, insensitive
    

• Primary varicella
  
• Herpes simplex virus (HSV)
  
• Cellulitis
  
• Poison Ivy
  
• Insect bites
  
• Bullous impetigo
  
• Molluscum contagiosum
  
• Trigeminal neuralgia
  
• Angina
  
• Biliary/renal colic
  
• Radiculopathy
  
• Bell palsy
  
• Peripheral vertigo
  
• Conjunctivitis (nonherpetic)
  
• HSV keratitis
  

TREATMENT

• Zoster is contagious and may cause varicella in nonimmune health care workers:
  
  • Lesions should be covered
    
  • Maintain universal precautions
    

• Generally a self-limited disease
  
• Goals of treatment are to decrease pain and duration of illness, and to prevent PHN
  
• Immunocompetent patient
  
  • Antiviral therapy
    
    • PO valacyclovir has easiest dosing and seems to be the most effective
      
    • May also use PO acyclovir (cheapest option) or famciclovir
      
    • Should be started within 72 hr of rash, but some experts recommend starting later if new vesicles are still appearing
      
    • Speeds acute healing and resolution of acute pain
      
    • Unclear if decreases the rate of PHN
      
  • Analgesics
    
    • Over-the-counter agents (mild disease)
      
    • Long-acting opioids
      
  • Corticosteroids (controversial)
    
    • Several studies showed modest improvement in cutaneous healing and acute neuritis
      
    • Does not help prevent PHN
      
    • If not otherwise contraindicated, consider in patients with severe disease or CNS involvement
      
• Immunocompromised patient
  
  • Antiviral therapy
    
    • IV acyclovir
      
  • Analgesics
    
    • As above
      
  • Corticosteroids
    
    • As above
      
• Herpes zoster ophthalmicus
  
  • Necessitates ophthalmologic consultation
    
  • Valacyclovir PO as above
    
  • IV acyclovir if immunocompromised or cranial nerve involvement
    
  • Erythromycin ointment for secondary bacterial infection
    
  • Topical cycloplegic if associated iritis
    
  • Ophthalmologist may recommend topical steroids
    
• PHN
  
  • Antivirals not indicated
    
  • Long-acting opioids
    
  • Tricyclic antidepressants are effective
    
  • Gabapentin and pregabalin may also be helpful
    
  • Topical lidocaine provides short-term relief
    
• Postexposure prophylaxis
  
  • VariZIG is recommended within 72 hr of exposure for the following patients:
    
    • Immunocompromised
      
    • Pregnant
      
    • Exposed premature neonates born <28 wks gestation
      
    • Exposed premature neonates born >28 wks gestation to seronegative mom
      
    • Neonates born to mother with symptomatic varicella between 5 days predelivery and 2 days postdelivery
      
    • Must wait 5 mo before giving subsequent vaccine
      
• Vaccine
  
  • Zostavax (Merck) recommended for all patients over the age of 60 (unless immunocompromised)
    
  • Does not reduce risk of recurrence or PHN in patients with zoster
    

• Same treatment as immunocompetent patients
  
• Vaccine contraindicated in pregnancy
  

Neonatal zoster requires treatment with IV acyclovir

• Antivirals:
  
  • Valacyclovir 1 g PO q8h × 7 days, Acyclovir 800 mg PO q4h × 7–10 days, Acyclovir 10 mg/kg IV q8h × 7 days
    
• Analgesics:
  
  • Acetaminophen 500 mg PO q6h; not to exceed 4g/d
    
  • Ibuprofen 600 mg PO q6h
    
  • Oxycodone CR 10 mg PO q12h
    
  • Amitriptyline 25 mg PO qhs, increase as tolerated to 100 mg daily
    
  • Cyclopentolate ophthalmic 1% apply 1 gtt q8h to affected eye
    
• PEP:
  
  • Varicella zoster immunoglobulin (VariZIG): 125 U IM/IV per 10 kg body weight, up to max. of 625 U
    
• Vaccine:
  
  • Zostavax (Merck) one-time SC injection
    

• Antivirals:
  
  • Famciclovir 500 mg PO q8h × 7 days
    
  • Foscarnet: 90 mg/kg IV as 2 hr infusion every 12 hr (acyclovir-resistant immunocompromised patient)
    
• Antibiotics:
  
  • Erythromycin ophthalmic ointment USP 0.5% apply 1 in q4h to affected eye
    
• Analgesics
  
  • Gabapentin: 100–300 mg daily increasing 100–300 mg every 3 days until adequate response or max. 3,600 mg/d
    
  • Pregabalin: Start 50 mg PO q8h or 75 mg PO q12h, increase to 100 mg q8h within 1 wk
    
  • Lidocaine patch 5%: Apply up to 3 patches for max. 12 hr within a 24 hr period for severe pain
    
• Corticosteroids:
  
  • Prednisone: Taper over 7 days (do not
    
  • extend beyond duration of antiviral therapy)
    

FOLLOW-UP