MODEL RELEASED. Chickenpox. Young boy with chickenpox sits in bed with his unaffected younger brother. Chickenpox (or varicella) is a common infectious disease of childhood. The disease is characterized by headache, fever and malaise followed by eruption of a rash over most of the body. The rash appears in crops and consists of clusters of small, red, itchy spots that become fluid filled blisters, 2 to 3mm in diameter, within a few hours. Rest is usually all that is needed for complete recovery. Calamine lotion can ease the itchiness and paracetamol can be taken to reduce fever. The disease is more serious in adults or children taking immunosuppressive drugs.