How do you diagnose VZV infection?

For varicella, the physical findings of lesions in various stages of development (papules, vesicles, pustules, and erosions), especially with a history of exposure to an individual with varicella (or zoster), is generally enough to make the diagnosis. The diagnosis of herpes zoster is also often made on the basis of physical findings. A Tzanck smear may be useful. If additional laboratory evaluation is indicated, immunohistochemical testing to detect viral-specific antigens in infected cells is recommended. A viral culture may be performed, although culturing VZV is more difficult and takes longer than culturing HSV. Use of PCR has become more commonly available. VZV serology is rarely useful for diagnosis.