Chickenpox is an acute infectious disease caused by varicella-zoster virus infection, with a predominantly skin rash, but after the rash fades and scars, if picked off it usually does not leave a scar, as long as the rash is not infected. The incubation period of chickenpox is generally 4-21 days, and the virus is transmitted mainly through the nasopharyngeal droplets of the patient, who is the only source of infection and is very contagious. The infectious period lasts from two days before to five days after the rash appears. A dry and crusty rash is not infectious. After being diagnosed with chickenpox, children are advised not to go to school until the chickenpox scabs have completely dried. Chickenpox can be contracted at any age, but children are more susceptible and generally have milder symptoms after contracting chickenpox.