Sarah Richardson, age 9, of Hoffman Estates, Ill., for her question:

WHAT ARE CHICKEN POX?

One of the most common illnesses of children is a generally mild, contagious disease called chicken pox or varicella. It takes between 14 and 21 days from the time of exposure to the disease and the appearance of first symptoms.

With chicken pox the first symptom is a skin rash accompanied by fever, headache and aching muscles. Red blotches on the back or chest develop, and they often become blistered and filled with a milky fluid. After a few days the blisters dry up and are covered with scabs.

If you come down with chicken pox, great care should be taken to prevent scratching of the skins since there is always a danger of infection or the development of permanent scars.

A child who has chicken pox once usually does not get it again.