MODEL RELEASED. Chickenpox. Young girl suffering from chickenpox (varicella) being attended to by an adult. Chickenpox is a highly infectious disease caused by a herpesvirus that is transmitted by airborne droplets. Following a mild fever, an itchy rash breaks out that develops into blisters and then scabs. Treatment includes the use of painkillers such as paracetamol for fever and the application of calamine lotion to alleviate the itchiness of the skin. Chickenpox is rare in adults since infection in childhood generally confers life-long immunity. An attack in adults often takes a more severe form.