Model released. Two year old boy with chickenpox (varicella). The boy's mother is treating his rash with calamine lotion to relieve itching and discourage scratching. In childhood, chickenpox is a mild infectious disease characterised by a rash and slight fever. It is caused by a herpesvirus which is transmitted by airborne droplets. After an incubation period of 11-18 days a mild fever develops followed by an itchy rash of dark red pimples which spread from the trunk to the face, scalp and limbs. The pimples develop into blisters and then scabs which drop off after about 12 days. The only treatment is bed rest, calamine lotion, and fever-reducing drugs such as Calpol.