Shingles, also called herpes zoster, is an infection caused by the varicella zoster virus (VZV), the same virus that causes chickenpox. It can cause nerve inflammation and intense pain, a reddened rash, and blisters (vesicles) that break open and crust over before slowly resolving. In most cases, the rash and pain subside within a few weeks, but some of those affected may have severe pain that lingers for months or even years.
When someone is first exposed to VZV, usually in childhood, the person develops chickenpox, a common, highly contagious, primary systemic infection that causes multiple "crops" of vesicles in multiple locations on the body. Chickenpox is passed from person to person through direct contact with fluid from the blisters or coughing or sneezing. Once the chickenpox has resolved, the virus becomes dormant, persisting in a latent form at the base of sensory nerve cells near the spinal cord and brain. Normally, the body's immune system maintains this latency and produces sufficient VZV antibodies to protect against future exposures.
Later in life, typically decades later, with increasing age and associated natural decline in immunity, and/or when a person's immune system becomes weakened such as with HIV/AIDS, certain cancers and their treatments, or with immunosuppressive drugs given after an organ transplant, the virus can re-activate and cause shingles. VZV begins to reproduce again and moves outward along the length of one or more sensory nerves to the surface of the skin. This can cause symptoms associated with shingles, including a ribbon or band of lesions on one side of the trunk, face, or arm corresponding to the section of skin (dermatome) that the affected nerve serves.
Shingles is less contagious than chickenpox, but the virus may be passed to another person through contact with an open vesicle. The person exposed will only become infected if he or she has not been previously exposed to a VZV infection or has not been vaccinated – and will develop chickenpox, not shingles.
Almost all adults in the U.S. have had chickenpox and about one million people a year get shingles in this country. It is most common in those over 60 years of age and in those with weakened immune systems. It is estimated that 50% of Americans will get shingles by the time they are 80 years old.
Although most people will only have shingles once, the virus can potentially re-activate and cause shingles again. Those with weakened immune systems may have difficulty regaining and maintaining virus latency. A baby who is born with chickenpox is at an increased risk for developing pediatric shingles. This is a rare event that sometimes occurs when a woman has chickenpox, or – even more rarely – develops shingles, during her pregnancy.
Symptoms and Complications
Itching, tingling or burning pain in a specific location, such as one side of the waist or face, may start several days before other signs of shingles emerge. The pain may be moderate or severe and the skin may be hypersensitive. A person may also have nonspecific symptoms such as fever, fatigue, muscle aches, headache, nausea, or chest pain.
A reddened rash then appears and eruptions of blisters (vesicles) develop over several days within one or two characteristic bands of skin (dermatomes) on one side of the body at the waist, face, or other location. There may be few or many vesicles and, in some cases, they may merge together. The vesicles typically have a clear fluid in them that turns cloudy over time.
At some point, the vesicles burst, become crusty, and then begin to resolve over the next few weeks. In most cases, the skin does not scar unless it is damaged by scratching or unless a secondary bacterial infection or complication develops. Rarely, a person may have shingles without vesicle formation.
A variety of other symptoms and complications may be seen, depending upon which nerves are affected. Symptoms can be atypical and/or more severe and persistent in those who have weakened immune systems. Complications may include:
- Postherpetic neuralgia (PHN) – this is severe pain from damaged nerves that persists long after other signs of shingles have resolved, for weeks to months or even years in some people. PHN can occur in up to half of untreated people 60 years of age or older.
- Herpes zoster opthalmicus (HZO) – when shingles occurs next to the eye, it can cause a variety of eye-related symptoms, facial scarring, and it can threaten a person's vision. Eye involvement may appear weeks after other symptoms have resolved.
- Ramsay Hunt syndrome – when shingles involves the facial nerve and ear, it can cause facial palsy, persistent abnormal sounds in the ear (tinnitus), hearing loss, a loss of taste, and vertigo. Those affected may not fully recover.
- Herpes zoster encephalomyelitis (meningoencephalitis or encephalitis) – central nervous system involvement may occur in some immune-compromised or severely ill people. This form of shingles can be life-threatening.
- Disseminated herpes zoster – shingles that affects many areas and clinically appears to be chickenpox. It may sometimes occur in those with weakened immune systems.
The diagnosis of shingles is primarily clinical, based upon the characteristic pain and band of rash and blisters (vesicles). Laboratory testing for varicella zoster virus (VZV) may sometimes be performed to confirm or rule out VZV when a person has atypical symptoms and/or complications that may be due to another cause. It may also be performed for organ transplant recipients or pregnant women to help diagnose a current infection and to determine whether the person has been previously exposed to VZV – to help evaluate their immune status. Read more about VZV tests.
The best treatment for shingles and chickenpox is prevention. A varicella vaccine is now routinely given as part of childhood immunizations. It is intended to prevent chickenpox as well as latent VZV and so decrease the number of people who get shingles later in life. There is also now a Herpes zoster vaccine approved by the Food and Drug Administration (FDA) for use in people 50 and older who have had chickenpox called Zostavax®, which is intended to decrease the risk of developing shingles and the risk of postherpetic neuralgia. While there is no guarantee that someone who receives either of these vaccines will not get chickenpox or shingles, they reduce the severity of the disease and the likelihood of complications for someone who does get either of these infections.
Those who do get shingles are treated with antiviral medications to decrease symptom severity and shorten the duration of the illness. Treatment may also reduce the risk of developing postherpetic neuralgia and reduce its duration. Antivirals are most effective when started within three days of rash development.
Topical therapies and pain medications may be used to relieve the symptoms associated with shingles. Those who have shingles with eye, ear, or central nervous system complications may need to consult with specialists.
Those with severely weakened immune systems may sometimes be given zoster immune globulin, as an external source of VZV antibodies, to lessen the severity of the condition.
Elsewhere On The Web
National Institute of Neurological Disorders and Stroke: Shingles, Hope Through Research
Centers for Disease Control and Prevention: Shingles (Herpes Zoster) Vaccination
National Institute on Aging: Shingles
National Shingles Foundation
Mayo Clinic: Postherpetic neuralgia
Mayo Clinic: Ramsey Hunt syndrome
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
MayoClinic.com. Shingles. Available online at http://www.mayoclinic.org/shingles/ through http://www.mayoclinic.org. Accessed November 2013.
NIH Senior Health. About Shingles. Available online at http://nihseniorhealth.gov/shingles/aboutshingles/01.html through http://nihseniorhealth.gov. Accessed November 2013.
Centers for Disease Control and Prevention. Shingles (Herpes Zoster). Available online at http://www.cdc.gov/shingles/ through http://www.cdc.gov. November 2013.
National Institute of Neurological Disorders and Stroke. Shingles Information Page. Available online at http://www.ninds.nih.gov/disorders/shingles/shingles.htm through http://www.ninds.nih.gov. Accessed November 2013.
American Academy of Dermatology. Shingles. Available online at http://www.aad.org/dermatology-a-to-z/diseases-and-treatments/q---t/shingles through http://www.aad.org. Accessed November 2013.
Sources Used in Previous Reviews
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