How long is someone with chicken pox contagious?
The most contagious time occurs when the person is going through the cold-like symptoms which is usually two to five days before the rash shows up. Therefore, the time in which someone is most contagious occurs before the person even knows he has chicken pox! After the rash appears, the person is infectious for about 5 days or until all the lesions have begun crusting over. This does not mean the lesions need to have gone away or fallen off, just crusted over.
