What is shingles, and why does it occur only in older people?
Shingles is a condition caused by a virus (herpes zoster) that also causes chicken pox. It is believed that the virus causes chicken pox in childhood, then lies dormant in nerve tissue for years or decades until it is reactivated to cause shingles. While shingles can affect people at any age, it is more common and often more painful in older adults. Reactivation of herpes virus is heralded by localized pain along the route of a nerve, as the virus causes the nerve tissue to become inflamed. After 2 or 3 days of pain that is often severe, the skin erupts with red and fluid-filled lesions along the route of the affected nerve. The skin lesions resemble those of chicken pox. As the condition progresses, new lesions continue to form and pain continues to be severe. The active phase may continue for a week or longer, but healing may require several weeks, especially in older adults. In some cases, branches of the optical nerve may be affected and vision may be impaired or even lost. A derma
