Definition

A common condition that occurs when the virus that causes chickenpox is reactivated in the body. After having chickenpox, the virus stays inactive in the body, usually in the nerves along the spinal cord or at the base of the skull. The virus can become active again many years later and cause herpes zoster. Herpes zoster is marked by a painful rash that usually appears as small clusters of blisters. The blisters often form a band across the skin on one side of the body, especially on the chest, back, waist, or face. The pain in the affected area can last for many weeks or months after the rash disappears. Other symptoms may include fever, chills, headache, fatigue, and upset stomach. Herpes zoster is most common in older adults and in those who have a weakened immune system. It cannot be passed from person to person, but those who have never had chickenpox or the chickenpox vaccine can develop chickenpox if they come in contact with a person who has herpes zoster. Vaccines are available to prevent herpes zoster. Also called shingles.