Chickenpox is caused by an infection with the varicella-zoster virus and is highly contagious, spreading through contact with one another. Generally, the initial symptoms of chickenpox appear as small blisters on the body, which tend to increase in number within a day or two. Some blisters may burst or erode, particularly on the scalp, and are often accompanied by feverish symptoms. The natural course of the disease is about a week, and mild cases can recover spontaneously within a week. It is recommended that if diagnosed with chickenpox, antiviral medication should be administered and isolation should be practiced to avoid contact with children or older adults with weakened immune systems. Generally, treatment for about a week can lead to recovery.