This picture shows chickenpox lesions on the chest. A vaccine for chickenpox has been approved for use in the United States. Chickenpox remains a common infectious disease, and most people are familiar with its appearance. (Image courtesy of the Centers for Disease Control and Prevention.)

This is a typical chickenpox lesion seen here on the leg. (Image courtesy of the Centers for Disease Control and Prevention.)

Chickenpox is caused by the varicella-zoster virus, a member of the herpesvirus family. The same virus also causes herpes zoster, shingles, in adults. Chickenpox is extremely contagious, and can be spread by direct contact, droplet transmission, and airborne transmission. Symptoms range from fever, headache, stomach ache, or loss of appetite before breaking out in the classic pox rash. The rash can consist of several hundred small, itchy, fluid-filled blisters over red spots on the skin. The blisters often appear first on the face, trunk, or scalp and then spread to other parts of the body.

This chest x-ray shows cloudiness throughout the lungs, caused by acute pneumonia following chickenpox. Pneumonia, as a complication of chickenpox, rarely occurs in children, but occurs in about one-fifth of adults.

This is a close-up picture of chickenpox. Early chickenpox lesions consist of small red papules which quickly fill with a yellowish or straw colored fluid to form small blisters (vesicles), as seen in this photograph. Later, these vesicles will rupture forming shallow erosions that crust over and then ultimately heal.