Casey Gallagher, MD, is board-certified in dermatology. He is a clinical professor at the University of Colorado in Denver, and co-founder and practicing dermatologist at the Boulder Valley Center for Dermatology in Colorado.
Shingles, also known as herpes zoster (HZ), is a painful rash that's caused by a reactivation of the varicella-zoster virus (VZV), which is also responsible for chickenpox.
Besides the vesicles (fluid-filled sacs) and discomfort that are the main symptoms of shingles, many people continue to have persistent pain after the rash heals—a condition called postherpetic neuralgia (PHN).
Shingles can be treated with antiviral medications and symptom-relief strategies, but even more important to managing shingles is prevention. People who receive the chickenpox vaccine will avoid shingles because they are protected from infection by varicella in the first place. Your risk for getting shingles increases as you get older.1 For healthy adults age 50 and over, there are two vaccines available.
The shingles condition itself is not contagious, but the varicella-zoster virus is contagious. Once the shingles rash develops on the skin, it's possible to pass on the virus (but only to a person who hasn't been vaccinated against chickenpox) until the blisters crust over and form scabs—anywhere from 10 to 14 days. After that point, the risk of passing on the virus is much lower.
The classic shingles rash presents in the second phase of shingles (eruptive phase) as a cluster of tiny, pimple-like blisters that are painful, red, tingly, and itchy. The rash is usually localized to one strip of skin on only one side of the body; not scattered over the entire body as with chickenpox. The rash area may be itchy and/or painful for weeks or months after the vesicles scab.
Shingles is caused by a reactivation of the varicella-zoster virus (VZV), which lies dormant after the first infection with chickenpox. Why the virus reappears isn't well understood, but one of the main factors is a weakened immune system. A long-standing hypothesis points to stress as a major cause, but current research doesn't fully support this theory.
In general, a case of shingles may last for three to five weeks. The first (prodromal) phase is marked by fatigue, fever, and tingling pain on one side of the body. A few days later, the rash will appear. The rash will turn into fluid-filled vesicles a few days after that, then scab over in 10 to 14 days. The scabs will likely clear up in a couple of weeks, unless they're reopened by scratching.
Most people will only get shingles once, but because the virus stays dormant in the body, it is technically possible to get shingles a second time. This is rare, however. The best way to prevent shingles from occurring again is to get the shingles vaccine, which can help prevent a recurrence even if you've already had shingles.
The primary aim of treatment is to prevent more vesicles from forming in order to stop virus replication in its tracks and prevent more severe pain. Prescription oral antiviral drugs are necessary and most effective within 72 hours of an outbreak. Home remedies for symptom relief are also helpful: oatmeal baths for itching, Tai Chi for gentle exercise, and plenty of rest and fluids.
A class of drugs used to treat antiviral infections. With shingles, starting antiviral therapy within 72 hours of the onset of the infection has shown to be the most helpful. The three oral antivirals used with shingles are Zovirax (acyclovir), Famvir (famciclovir), and Valtrex (valacyclovir).
An inflammation of the brain, most commonly caused by viral infection. Mild cases may have no symptoms, while more severe cases can interfere with brain function and have lasting effects. Rarely, the varicella-zoster virus responsible for shingles can spread to the brain, causing encephalitis.
In a small percentage of cases (10 to 15%),1 herpes zoster may affect the sensory nerve supplying the eye known as the ophthalmic nerve. If left untreated, ophthalmic shingles may lead to permanent eye damage or even loss of the eye. If the shingles rash shows up near the eye, it's essential to be treated by an ophthalmologist immediately.
A chronic pain condition arising as a complication of shingles. Postherpetic neuralgia (PHN) is marked by consistent pain, burning, and tingling that occurs at the location of the shingles rash—but after the rash has resolved. The pain is typically more severe than the pain of having shingles. PHN itself isn't dangerous, but it can negatively affect your quality of life.
The spread of a harmful virus inside your body. In the case of shingles, the varicella-zoster virus (VZV) usually strikes in childhood. After the initial infection, VZV lies dormant in the ganglia (part of the central nervous system) with the potential to be reactivated and cause shingles years later.
Centers for Disease Control and Prevention. Shingles (herpes zoster): Clinical overview. Updated August 14, 2019.
Centers for Disease Control and Prevention. What everyone should know about shingles vaccines. Updated May 31, 2018.
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Centers for Disease Control and Prevention. Shingles treatment. Updated July 1, 2019.
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Naveen KN, Pradeep AV, Kumar JS, Hegde SP, Pai VV, Athanikar SB. Herpes zoster affecting all three divisions of trigeminal nerve in an immunocompetent male: a rare presentation. Indian J Dermatol. 2014;59(4):423. doi:10.4103/0019-5154.135548
Xing X, Sun K, Yan M. Delayed initiation of supplemental pain management is associated with postherpetic neuralgia: A retrospective study. Pain Physician. 2020 Jan;23(1):65-72.
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