Atypical varicella exanthems associated with skin injury.

Varicella is a common childhood disease with a typical exanthem. We present four children with severe, localized disease, all associated with some form of trauma to the skin during the incubation period: a 3 1/2-year-old boy sustained wasp stings on the hand, a 5-year-old boy received extensive sun exposure, a neonate had iatrogenic trauma to her arm, and a 13-year-old boy underwent knee arthroscopy and was wearing a cast. It is postulated that such injuries to the skin either allowed more virus-infected cells to enter the skin at the sites, or that factors such as insect venom and ultraviolet light altered local immunity to varicella zoster virus.