Chickenpox (varicella) is a common illness that causes an itchy rash and red spots or blisters (pox) all over the body. It is most common in children. But most people will get chickenpox at some point in their lives if they haven't had the chickenpox vaccine.
Chickenpox can cause problems for pregnant women, newborns, teens and adults, and people who have immune system problems that make it hard for the body to fight infection. Chickenpox usually isn't a serious health problem in healthy children. But a child with chickenpox needs to stay home from school.