Definition

Chickenpox, also called varicella (pronounced VAR-ih-SEL-uh), is a common and very infectious childhood disease, which sometimes affects adults. Chickenpox produces an itchy rash with blisters that lasts about a week. Fever and other symptoms may also be present. A single attack of chickenpox generally produces lifelong immunity (protection) against the disease, which means once you have chickenpox you usually never have it again.

Chickenpox can almost always be treated at home. The symptoms are unpleasant, but they are rarely dangerous. If complications develop, professional medical attention is essential.

Description

Chickenpox is caused by the varicella-zoster virus (a herpes virus; see herpes infections entry) and affects about four million Americans each year. Of this number, five thousand to nine thousand require hospitalization. About one hundred people die of the disease each year.

A person becomes infectious (able to pass on the virus) a day or two before a...