Varicella-zoster virus (VZV) is one of the 8 herpesviruses of humans and is the cause of chickenpox (varicella) and shingles (zoster). Chickenpox, the exanthem caused by primary infection with VZV, usually occurs in children. Shingles, the clinical syndrome of segmental, unilateral, exanthem, and neuralgic pain due to reactivation of latent VZV infection, usually occurs many years after the primary infection. In the immunodeficient person, both primary and reactivated VZV infection can lead to severe generalized virus dissemination, the life-threatening form of VZV infection. The availability of antiviral agents for management of VZV infection has raised the importance of recognizing this infection in high-risk groups. Prior to the introduction of the VZV vaccine in the United States in 1995, approximately 4 million cases of chickenpox occurred each year, 83% in children younger than 9 years. There are an estimated 1 million cases of herpes zoster in the United States per year, with the annualized incidence of 1.5 to 3.0 cases per 1000 persons, and the incidence and severity of disease increases with age. A VZV vaccine was approved in 2006 for prevention of shingles in persons older than 60 years.

CLINICAL PRESENTATION

Chickenpox

In healthy unvaccinated children, VZV infection manifests as a vesicular exanthem often associated with prodromal malaise, pharyngitis, rhinitis, and abdominal pain. At the median, the rash appears 15 days after VZV exposure; the range is 10 to 21 days.