Although the symptoms of chickenpox typically fade after the initial infection (usually in childhood), the virus remains buried in nerve cells. It may remain dormant in some people for the rest of their lives, but it may resurface in others. Shingles is the second stage of the chickenpox viral infection.
Because it belongs to the same virus family as herpes zoster, shingles is frequently referred to as "herpes zoster" or "zoster."
Shingles is not caused by the herpes virus, which is responsible for genital herpes and cold sores.
The first symptom of shingles is usually a burning or tingling pain or an itch, on only one side of the body.
Pain, itching or tingling in the area where the rash may form is common before the rash appears. Fever, headache, chills and an upset stomach are some of the other shingles symptoms.
A rash of fluid-filled blisters, similar to chickenpox, emerges in one area on one side of the body after several days or a week.
Discomfort from shingles can range from minor to severe. Some people are mostly itchy, while others are irritated by even the tiniest touch or air.
The most common location for shingles is a band, called a dermatome, spanning one side of the trunk around the waistline. The second most prevalent site is around the eye and on the forehead on one side of the face.
However, shingles can affect any portion of the body. The total number of lesions often varies and some rashes combine to form an area that resembles a serious burn. Other people may only have a few scattered lesions that do not cause any significant symptoms.
After 3-5 days, most healthy people's blisters start to scab over. The rash normally goes away in two to four weeks. The pain and itch that accompany the lesions fade away and the blisters leave no scars. Other people may have sensory symptoms that linger for a few months.
Although rare, shingles can lead to pneumonia, hearing problems, blindness, brain inflammation (encephalitis) or death. For about one person in five, severe pain can continue even after the rash clears up. This pain is called post-herpetic neuralgia. As people get older, they are more likely to develop post-herpetic neuralgia, which is more likely to be severe.
Most commonly, a person has only one episode of shingles in their lifetime. Although rare, a second or even third case of shingles can occur.
A person with a shingles rash can pass the virus to someone, usually a child, who has never had chickenpox, but the child will develop chickenpox, not shingles. The child must come into direct contact with the open sores of the shingles rash during the blistering phase. Once the rash has developed crusts, the person is no longer contagious.
Merely being in the same room with a shingles patient will not cause the child to catch chickenpox because, during a shingles infection, the virus is not generally in the lungs and therefore can't be spread through the air.
The risk of spreading shingles is low if the rash is covered. People with shingles should keep the rash covered, not touch or scratch the rash and wash their hands often to prevent the spread of the chickenpox virus (varicella). Once the rash has developed crusts, the person is no longer contagious.
A shingles vaccine is available for use in people 60 years old and older to prevent shingles.
The older a person is, the more severe the effects of shingles typically are, so all adults 60 years old or older should get the shingles vaccine. The shingles vaccine is specifically designed to protect people against shingles and will not protect people against other forms of herpes, such as genital herpes. The shingles vaccine is not recommended to treat active shingles or post-herpetic neuralgia (pain after the rash is gone) once it develops.
About 25% of all adults, mostly otherwise healthy, will get shingles during their lifetimes, usually after age 40. The incidence increases with age so that shingles is 10 times more likely to occur in adults over 60 than in children under 10.
People with compromised immune systems from the use of immunosuppressive medications or serious illnesses, such as cancer or HIV, are at special risk of developing shingles. These individuals also can have recurrent shingles and may have shingles that never heal. Most people who get shingles strengthen their immunity to the chickenpox virus and will not get the disease for another few decades.
Many mothers-to-be are concerned about any infection contracted during pregnancy. Some infections can be transmitted to the baby either across the mother's bloodstream to the fetus or during the birth process. Chickenpox virus infection during pregnancy poses some risk to the unborn child, depending upon the stage of pregnancy. During the first 30 weeks, maternal chickenpox may, in some cases, lead to congenital malformations. Such cases are rare and experts differ in their opinions on how great the risk is. Most experts agree that shingles in a pregnant woman, a rare event, is even less likely to cause harm to the unborn child.
If a pregnant woman gets chickenpox between 21 to 5 days before giving birth, her newborn can have chickenpox at birth or develop it within a few days. But the time-lapse between the start of the mother's illness and the birth of the baby generally allows the mother's immune system to react and produce antibodies to fight the virus. These antibodies can be transmitted to the unborn child and help fight the infection. Still, a small percentage of babies exposed to chickenpox in the 21 to 5 days before birth develop shingles in the first five years of life because the newborn's immune system is not fully functional.
If the mother contracts chickenpox at the time of birth, her immune system has not had a chance to mobilize its forces and create very many antibodies that can fight VZV. Although some of the mother's antibodies will be transmitted to the newborn via the placenta, the newborn will have little ability to fight off the infection because its immune system is immature. If these babies develop chickenpox as a result, it can be fatal. They are given zoster immune globulin, a preparation made from the antibody-rich blood of adults who have recently recovered from chickenpox or shingles, to lessen the severity of their chickenpox.
Shingles attacks can be made less severe and shorter by using prescription antiviral drugs such as acyclovir, valacyclovir or famciclovir. These medications should be started as soon as possible after the rash appears.
Antiviral drugs can reduce by about half the risk of being left with postherpetic neuralgia, which is chronic pain that can last for months or years after the shingles rash clears.
Doctors recommend starting antiviral drugs at the first sign of the shingles rash or even if the telltale symptoms indicate that a rash is about to erupt.
A doctor may prescribe anti-inflammatory corticosteroids such as prednisone if the eye or other facial nerves are affected.