Varicella Zoster

OVERVIEW

• VZV = an alpha herpes virus
• 90% of adults have evidence of infection
• spread via droplet excreted from the throat of patients with chicken pox OR via contact with vesicle fluid in chicken pox or shingles.
• after infection:
  1. asymptomatic
  2. chicken pox
  3. shingles (herpes zoster)

• site of latency = nerve cell body (spinal cord and cranial nerves)

CLINICAL FEATURES

Chickenpox

• febrile response
• vesicular rash that appears in crops
• generalized lymphadenopathy

Shingles

• blistering rash that always stops at the midline
• risk factors: increased age, immunosuppression or deficiency, stress

INVESTIGATIONS

• clinical diagnosis
• viral isolation from tissue culture
• electron microscopy
• antigen detection

MANAGEMENT

• aciclovir
• prevention = immunization with live vaccine or zoster immunoglobulin

COMPLICATIONS

• chicken pox -> pneumonia, congenital varicella or neonatal chicken pox
• shingles -> post-herpetic neuralgia, zoster keratitis, motor-nerve paralysis

Risk factors for developing pneumonia

• Smoker
• Contact with index case
• > 100 spots
• Duration of fever
• Chronic Lung Disease
• 3rd trimester pregnancy
• Immunosuppression