The VZV is a DNA herpesvirus.12,13 It is transmitted from person to person by direct contact with vesicular fluid; inhalation of aerosols from vesicular fluid or infected respiratory tract secretions; and less frequently, by contact with freshly contaminated articles and environmental surfaces. The average incubation period is 14 to 16 days. The virus is transmissible from about 1 to 2 days prior to the onset of rash until all lesions have crusted.
The VZV is responsible for both chickenpox and herpes zoster infections. Chickenpox is characterized by acute onset of diffuse maculopapular rash, which quickly develops into vesicles that break down and crust, typically within 4 to 7 days. The lesions commonly occur in successive crops and predominate on the trunk and face, but may appear on the scalp, high in the axilla, on mucous membranes of the mouth and upper respiratory tract, and on the conjunctivae.
Herpes zoster, a localized painful vesicular rash, is the clinical manifestation of reactivated latent VZV. Vesicles with an erythematous base are restricted to skin and mucosal tissues innervated by sensory nerves of a single or associated group of the dorsal root ganglia. Lesions may appear in crops in irregular fashion along nerve pathways, are usually unilateral, and are deeper seated and more closely aggregated than those associated with chickenpox.
Infection with the VZV is vaccine-preventable. In the absence of acceptable evidence of immunity, active immunization is highly recommended for the prevention of VZV infections. There is one monovalent varicella vaccine (Varivax) licensed in the United States for use in adults. For adults 60 years or old a high-potency formulation (19,400 plaque-forming units) varicella vaccine (Zostavax) is also available for the prevention of herpes zoster (shingles).
Oral (acyclovir, valacyclovir, and famciclovir) and IV (acyclovir and foscarnet) formulations of antiviral agents are available to treat VZV infections. All susceptible individuals should also receive vaccination. Susceptible persons for whom the vaccine is contraindicated should be administered varicella-zoster immunoglobulin (VZIG) within 96 hours of exposure. Medical care is supportive to help relieve symptoms and to address complications such as bacterial infections.