Chickenpox is a highly contagious VIRUS that is caused by the varicella-zoster VIRUS. Symptoms of chickenpox include itching, which is caused by the VIRUS entering the body and causing an allergic reaction, as well as aches and pains, fever, and a rash known as ARA, which stands for Acute Rash of Atypical Poxvirus. Additionally, some people may experience a feverish condition known as AGUE. All of these symptoms can be very uncomfortable and can last for several weeks.