Herpes zoster (shingles) is a painful, blistering skin rash due to acute infection with the varicella-zoster virus, the virus that causes chickenpox.

See also: Ramsay Hunt syndrome

After you get chickenpox, the virus falls asleep (becomes dormant) in certain nerves in the body. Shingles occurs after the virus becomes reactive in these nerves after many years.

The reason the virus suddenly become active again is not clear. Often only one attack occurs.

If an adult or child is exposed to the herpes zoster virus and has not had chickenpox as a child or received the chickenpox vaccine, a severe case of chickenpox may develop, rather than shingles.

Herpes zoster can be contagious through direct contact in an individual who has not had chickenpox, and therefore has no immunity. Herpes zoster may affect any age group, but it is much more common in adults over 60 years old, in children who had chickenpox before the age of one year, and in individuals whose immune system is weakened.

The first symptom is usually one-sided pain, tingling, or burning. The pain and burning may be severe.

Red patches on the skin form, followed by small blisters that look very similar to early chickenpox. The blisters break, forming small ulcers that begin to dry and form crusts. The crusts fall off in 2 to 3 weeks.

The rash usually involves a narrow area from the spine around to the front of the belly area or chest. It may involve face, eyes, mouth, and ears.

Additional symptoms may include:

• Abdominal pain
• Chills
• Difficulty moving some of the muscles in the face
• Drooping eyelid (ptosis)
• Fever
• General ill-feeling
• Genital lesions
• Headache
• Hearing loss
• Joint pain
• Loss of eye motion (ophthalmoplegia)
• Swollen glands (lymph nodes)
• Taste problems
• Vision problems

Your doctor can make the diagnose by looking at your skin and asking questions about your medical history.

Tests are rarely needed, but may include taking a skin sample to see if the skin is infected with the virus that causes shingles.

Lab tests may show an increase in white blood cells and antibodies to the chickenpox virus but cannot confirm that the rash is due to shingles.

Herpes zoster usually disappears on its own. You may only need treatment to relieve pain.

Your doctor may prescribe an antiviral medicine called acyclovir. This drug helps reduce pain and complications and shorten the course of the disease. Desciclovir, famciclovir, valacyclovir, and penciclovir are similar to acyclovir and may be also be used.

The medications should be started within 24 hours of feeling pain or burning, and preferably before the blisters appear. The drugs are usually given in pill form, in doses many times greater than those recommended for herpes simplex or genital herpes. Some people may need to receive the medicine through a vein (by IV).

Strong anti-inflammatory medicines called corticosteroids, such as prednisone, may be used to reduce swelling and the risk of continued pain. These drugs do not work in all patients.

Other medicines may include:

• Antihistamines to reduce itching (taken by mouth or applied to the skin)
• Pain medicines
• Zostrix, a cream containing capsaicin (an extract of pepper) to prevent postherpetic neuralgia

Cool wet compresses can be used to reduce pain. Soothing baths and lotions, such as colloidal oatmeal bath, starch baths, or calamine lotion, may help to relieve itching and discomfort.

Resting in bed until the fever goes down is recommended.

The skin should be kept clean, and contaminated items should not be reused. Nondisposable items should be washed in boiling water or otherwise disinfected before reuse. The person may need to be isolated while lesions are oozing to prevent infection of others -- especially pregnant women.

Herpes zoster usually clears in 2 to 3 weeks and rarely recurs. If the virus affects the nerves that control movement (the motor nerves), you may have temporary or permanent weakness or paralysis.

Sometimes, the pain in the area where the shingles occurred may last from months to years. This pain, called postherpetic neuralgia, can be extremely severe. The elderly are at higher risk for this complication.

Involvement of the facial nerve may cause Ramsay Hunt syndrome, which can lead to loss of movement in the face, hearing loss, loss of taste, and other symptoms.

Other complications may include:

• Another attack of shingles
• Blindness (if lesions occur in the eye)
• Deafness
• Infection, lesions in body organs, encephalitis or sepsis in persons with weakened immune systems
• Postherpetic neuralgia
• Secondary bacterial skin infections

Call your health care provider if you have symptoms of shingles, particularly if you have a weakened immune system or if your symptoms persist or worsen. Shingles that affects the eye may lead to permanent blindness if you do not receive emergency medical care.

Avoid touching the rash and blisters of persons with shingles or chickenpox if you have never had chickenpox or the chickenpox vaccine.

The chickenpox vaccine may be recommended for teenagers or adults who have never had chickenpox. Medical evidence has shown that older adults who receive the vaccine are less likely to have complications from shingles. Adults older than 60 should receive the vaccine as part of routine medical care.

See: Chickenpox vaccine

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American Academy of Pediatrics Committee on Infectious Diseases. Prevention of varicella: recommendations for use of varicella vaccines in children, including a recommendation for a routine 2-dose varicella immunization schedule. Pediatrics. 2007;120(1):221-231.

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Tyring SK. Management of herpes zoster and postherpetic neuralgia. J Am Acad Dermatol. 2007;57:S136-S142.