Shingles is a localized infection due to the varicella-zoster virus, the same virus that causes chickenpox. It occurs only in people who have had chickenpox in the past and represents a reactivation of the dormant varicella virus. Why the virus reactivates in some individuals and not in others is unknown.
Disease Facts
The disease is primarily seen in the elderly, but occasionally occurs in younger individuals. It affects both sexes and all races with equal frequency and occurs sporadically throughout the year.
A person must have already had chickenpox in the past to develop shingles. Contact with an infected individual does not cause another person's dormant virus to reactivate. However, the virus from a shingles patient may cause chickenpox in someone who has not had it before.
The first sign is often a tingling feeling on the skin, itchiness or a stabbing pain. After several days, a rash appears beginning as a band or patch of raised dots on the side of the trunk or face. It then develops into small, fluid-filled blisters which begin to dry out and crust over within a few days. When the rash is at its peak, symptoms can range from mild itching to extreme and intense pain. The rash and pain usually disappear within three to five weeks.
The virus lies dormant in someone who has had chickenpox in the past. It can reactivate many years later.
A person exposed to a patient with shingles will not get shingles but may get chickenpox. The virus is present at the site of the rash and is contagious for a week after the appearance of lesions (blisters).
Shingles is not usually dangerous to healthy individuals although it can cause great misery during an attack. Anyone with shingles on the upper half of their face, no matter how mild, should seek medical care at once. There is some danger that the virus could cause damage to the eye resulting in blindness. Complications are rare but may include partial facial paralysis (usually temporary), ear damage or encephalitis (inflammation of the brain).
Most cases of shingles resolve on their own without specific treatment. Two medications available for use by physicians in treating immunocompromised patients are vidarabine and acyclovir.
Chickenpox must be prevented in order to prevent shingles. A live attenuated viral vaccine against chickenpox was licensed in the U.S. in 1995 and is very effective (95% efficacy).