Chickenpox is a contagious disease, principally of children and not commonly dangerous, caused by a virus and characterized by a low-grade fever and blistery rash.
Chickenpox (or chicken pox) is a highly contagious disease caused by primary infection with varicella zoster virus (VZV). It usually starts with vesicular skin rash mainly on the body and head rather than at the periphery and becomes itchy, raw pockmarks, which mostly heal without scarring. On examination, the observer typically finds lesions at various stages of healing. Chickenpox is an airborne disease spread easily through coughing or sneezing of ill individuals or through direct contact with secretions from the rash. A person with chickenpox is infectious one to two days before the rash appears. They remain contagious until all lesions have crusted over (this takes approximately six days). Immunocompromised patients are contagious during the entire period as new lesions keep appearing. Crusted lesions are not contagious. Chickenpox has been observed in other primates, including chimpanzees and gorillas.
Contributions by Kazvorpal, Midgley, and Jfdwolff.