Shingles

Shingles, also known as herpes zoster, is a viral infection that affects the nerves and causes a painful skin rash, most often on one side of the body. The rash typically lasts three to five weeks, but the pain may remain for months after the rash clears up.


Causes and associated factors
Shingles is caused by the varicella zoster virus, the same virus that causes chickenpox. After you've had chickenpox, the virus lies dormant (inactive) in your nerves. Later, often after decades, the virus may reactivate in the form of shingles. Although shingles appears to be a skin condition, it's actually a disease of the nervous system. Up to 20 percent of all people will develop shingles at some point in their lives.
Doctors don't know what causes the virus to reactivate, but shingles is more common in:

people who have weak immune systems, such as transplant recipients or those who have cancer, are infected with HIV or are receiving steroid or immune suppressing medications or radiation therapy
people who experience a temporary decrease in immunity due to stress from any source, such as surgery, injury, sunburn, the common cold or emotional stress
older adults (The risk of developing shingles increases with age. In fact, up to 75 percent of all cases occur after age 45. Healthy children rarely develop shingles.)
children who developed chickenpox when they were younger than age 18 months or whose mothers developed chickenpox late in pregnancy
Most people who develop shingles experience only one bout in a lifetime. However, people of all ages who have weak immune systems may experience repeated episodes.


Transmission
Remember, you must have been infected with chickenpox at some point to develop shingles. You can't catch shingles from someone who has shingles or chickenpox. However, you can develop chickenpox after contact with someone who has shingles.
If you've NEVER had chickenpox or the chickenpox vaccine, you can develop chickenpox through contact with someone who has shingles. For chickenpox to develop, the virus must enter your respiratory tract. This may happen when you come in contact with fluid from the blisters of someone who has shingles. For example, you may touch clothing or other articles that are freshly soiled by the fluid and then touch your nose, or you may breathe in air that contains tiny droplets of the fluid.

Rarely, someone who's already had chickenpox or the chickenpox vaccine may develop chickenpox after exposure to someone who has shingles. Normally, however, chickenpox only strikes once (or not at all, if you've been immunized).
The varicella zoster virus is less contagious during shingles than it is during chickenpox. As with chickenpox, shingles is contagious until the blisters form crusts.


Signs and symptoms
The first symptom of shingles is often skin that's painful, burning, itching, tingling or sensitive at the site where a rash will soon erupt. Rarely, you may also have a low-grade fever, mild chills, a general ill feeling, stomach upset or headache.
The change in skin sensation usually lasts from two to five days, but may continue for up to three weeks before you develop a blistering rash, which is often belt- or band-like. This rash typically develops on only one side of the body, usually on the face, neck, chest, back, abdomen, arm or leg. Rarely, the rash may be on both sides of the body.

In most cases, the blisters grow, become cloudy and form crusts within 14 days. The crusts typically fall off about three weeks after the initial symptoms appear. In rare cases, no rash develops.

A shingles infection typically lasts from three to five weeks. Before, during or after the rash, you may have pulsating, stabbing or piercing pain.

In healthy children, the rash is usually mild and not very painful. However, children whose immune systems aren't functioning normally may have severe symptoms and complications. Shingles is most painful for older people, and the risk of complications is more severe.

Contact your doctor right away if you suspect you're developing shingles, especially if you're age 50 or older or have a weak immune system.


Diagnosis
To diagnose shingles, the doctor will review your medical history and do a physical exam. Diagnosis is based on your symptoms and the characteristics of the rash. If needed, scrapings of the sores can be studied with a special test to verify the diagnosis.

Treatment
Currently, there's no cure for shingles. The goals of treatment are to alleviate your symptoms, make you more comfortable, and prevent or minimize any complications.
Your doctor may recommend a pain reliever such as acetaminophen or a stronger prescription pain medication. (Don't give aspirin or any product containing aspirin to anyone age 19 or younger due to the risk of Reye's syndrome, a rare but serious illness involving the brain and liver following a viral infection.)

Avoid scratching the rash. It may be helpful to apply cool, moist compresses to the affected areas. For closed blisters, oatmeal baths, baking soda or calamine lotion may help ease itching. Your doctor also may recommend an antihistamine, such as diphenhydramine.

Antiviral medications -- such as acyclovir (Zovirax, for example) or variants of acyclovir (such as famciclovir or valacyclovir) -- started within the first 24 to 72 hours of the initial rash can help clear up the rash sooner, as well as help reduce the duration and severity of postherpetic neuralgia and minimize other complications (described below). Treatment should begin as soon as possible. Antiviral medication may be useful until new sores are no longer forming. These medications are especially important for older adults, people who have weak immune systems and whenever the nerves serving the eyes or ears are affected.

Complications
Most people recover from shingles without any lasting complications. When complications develop, the most common is postherpetic neuralgia (PHN). With this condition, the nerve pain of shingles may continue or even worsen after the rash clears up. The pain can last weeks, months or even years. PHN is much more common in those older than age 50, especially when pain is severe or sensory impairment is significant. If you develop PHN, your doctor may recommend antidepressants, anticonvulsants, capsaicin cream (Zostrix, for example), or a local anesthetic patch to help with pain relief. Other complications may include:
serious eye injury, ranging from infection to blindness, if the nerves serving the eye are affected
hearing loss if the nerves serving the ear are affected
serious generalized infection
bacterial infection of the rash
scarring
weakness or paralysis of the affected area (partial facial paralysis or difficulty moving an extremity, for example), which is usually temporary
inflammation of the brain, spinal cord, lung or liver

Pregnancy-specific information
Shingles rarely develops during pregnancy. It appears to have no harmful effect for mother or baby. If you contract chickenpox during pregnancy, however, the infection can cause severe symptoms and pose significant risks to you and the baby.
If you're pregnant and haven't had chickenpox, avoid exposure to anyone who has an active case of chickenpox or shingles. If you're exposed to the virus and aren't already immune to it, your doctor may recommend an injection of varicella zoster immune globulin (VZIG). This shot contains varicella virus antibodies and may help prevent an infection or at least make it less serious.


Senior-specific information
The risk of developing shingles and postherpetic neuralgia increases with age. In fact, at least 50 percent of those ages 80 or older will experience at least one episode of shingles. Half of those adults will develop postherpetic neuralgia.

Prevention
Remember, you can't contract shingles if you've never had chickenpox. Studies are currently underway to determine the effectiveness of an experimental shingles vaccine in preventing the infection in older adults.