Vaccines and Your Immune System

Shingles

What Is Shingles? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Cathy Cassata
By Medically Reviewed by 
Reviewed:
Medically Reviewed

Shingles, also known as zoster or herpes zoster, is a viral infection caused by the varicella-zoster virus (VZV), the same virus that causes chicken pox.

Anyone who's had chicken pox can get shingles. After you've been infected with chickenpox, the varicella-zoster virus lies inactive in your body — mostly in spinal or cranial nerves — usually for many decades. If the virus reactivates, it can travel along nerve pathways to your skin and cause a painful rash to erupt.

Shingles is very rarely life-threatening, but it can be exceedingly painful. It’s been on the rise in the United States for the last couple of decades, according to the Centers for Disease Control and Prevention (CDC), though doctors aren’t sure why.

If you’re over 50 or over 18 and immunocompromised, you can get a shingles vaccine to prevent it.

Signs and Symptoms of Shingles

Shingles usually appears as a single stripe of blisters around the left or right side of the body. Less commonly, it can occur on one side of the face. It is almost always unilateral, meaning it involves only one side of the body.

But you can get a shingles rash anywhere: on your feet, your buttocks, your legs, even your genital area, according to a case report led by Anne Louise Oaklander, MD, PhD, an associate professor of neurology at Harvard Medical School and the director of the nerve unit and skin biopsy lab at Massachusetts General Hospital in Boston.


Shingles tends to show up most frequently on the torso, just because of the laws of probability, notes Joseph Safdieh, MD, a professor of neurology at Weill Cornell Medicine in New York City. In that area of your body, there are 24 nerves that can host the virus, compared with the 10 in your lower back.

Often, it’s not what the rash looks like, but what it feels like before and after it shows up, that signals the condition. Up to several days before the shingles rash appears, pain, itching, or tingling often occurs in the area where it will develop.

In the days before the rash appears, a variety of other flu-like symptoms of shingles can occur. You may experience:

You may even experience the pain but not the rash. Because the pain of shingles originates in the nerves, it may have a different quality than any other pain you have experienced before.

“Neuropathic pain is burning,” says Dr. Safdieh. “It’s both numb and painful at the same time, and can be provoked by touching the skin.” Your skin may be so sensitive that even sunlight can bring on a stabbing sensation.

Even if you aren’t sure you have shingles, you should still see a doctor right away, because immediate treatment can prevent complications like long-term nerve pain.

Learn More About the Signs and Symptoms of Shingles

Causes and Risk Factors of Shingles

The varicella-zoster virus — the virus that causes chicken pox and shingles — is part of a group of viruses called herpes viruses. This group also includes the viruses that cause cold sores (oral herpes) and genital herpes.

But the varicella-zoster virus is not the same virus that causes cold sores and genital herpes. The viruses that cause oral and genital herpes are herpes simplex 1 and herpes simplex 2.

If you’ve had chicken pox, you can get shingles. After the chicken pox is over, varicella-zoster lies inactive, mainly in spinal or cranial nerves. Sometimes the virus reactivates, and that’s when it travels along the nerves to erupt as a rash on your skin, causing shingles.

But the cause of the reactivation is still unknown, according to the National Institute of Neurological Disorders and Stroke.

Risk Factors

The risk of shingles increases as you age, which may be due to lowered immunity to infections as you grow older.

The following may also put you at increased risk of shingles, according to the CDC.

  • Certain cancers, such as leukemia and lymphoma
  • HIV or AIDS
  • Immunosuppressive medications, such as corticosteroids, which are used in the treatment of cancer and autoimmune conditions like rheumatoid arthritis, as well as drugs that are given to people who have undergone an organ transplant
Some research suggests that genetics may play a part, according to MedlinePlus.

If you have a first-degree relative — meaning a parent or sibling — who has had shingles, it may increase your risk of contracting it. A study published in the Journal of Clinical Virology found that nearly 44 percent of those with shingles had family members who had also developed it.

Is Stress a Risk Factor for Shingles?

You may have heard that someone got shingles because they were stressed, perhaps after the death of a relative, soon after a divorce, or at the end of a difficult semester at school.

But studies haven’t definitively proved that stress is a risk factor for shingles. Some research suggests that it is, according to MedlinePlus, while other research suggests that it’s not at all.

In a study published in March 2015 in Clinical Infectious Diseases, researchers reviewed the medical records of more than 39,000 people to see if cases of shingles increased after a difficult life event, and the authors found no evidence that stress is a trigger.

“There’s some controversy about the matter,” says Safdieh. “We know for a fact that stress can have an impact on the function of the immune system. If there’s stress, immunity is depressed, and I certainly see patients who tell me they were having a lot of stress when they got shingles.” But, he adds, “there are many people who are stressed and don’t get shingles, and many people who get them while they’re on vacation.”

If there is a link between stress and shingles, it’s probably not that the stress itself is putting a strain on the immune system — it may be that stress creates conditions that lower immunity. “Keep in mind,” says Safdieh, “that when you’re stressed, you don’t sleep and you don’t eat, and all these factors can play a role.”

RELATED: How Stress Affects Your Body, From Your Brain to Your Digestive System

How Is Shingles Diagnosed?

Once the rash appears, the signs and symptoms are usually clear enough for a doctor to make a diagnosis. Before the rash appears, or in cases where there is no rash, diagnosis is more challenging.

In cases with a less typical set of symptoms (pain without a rash, for example), lab testing can be helpful in confirming a diagnosis. A polymerase chain reaction (PCR) test may be used to detect varicella-zoster virus DNA in a skin lesion sample. Saliva samples may also be examined, but they're less reliable for herpes zoster than for varicella zoster, according to the CDC.

Herpes zoster is sometimes confused with herpes simplex. Skin symptoms may also be mistaken for impetigo, contact dermatitis, folliculitis, scabies, insect bites, psoriasis, papular urticaria, candidal infection, dermatitis herpetiformis, and drug eruptions, adds the CDC.

Shingles, however, has two features that distinguish it from conditions with similar symptoms: its flu-like onset and the severe pain that follows.

Prognosis of Shingles

It's uncommon to have shingles more than once, however, it's possible to get it two or more times.

In a study published in the journal Mayo Clinic Proceedings, the overall recurrence rate for shingles was 6.2 percent.

But for those whose immune systems were compromised, the rate was almost twice that. The authors of the Mayo Clinic paper also note that recurrences were more likely in women, in those older than 50, and in those who’d experienced shingles-related pain for 30 days or longer during their initial episode.

Why do people get shingles more than once? “Usually it's because immunity to zoster — and other infections — normally wanes over time,” explains Dr. Oaklander. “When you have chicken pox or shingles, it boosts your immunity for the next decade or so, but if you were immunosuppressed when you contracted the chicken pox or shingles, you might not mount a robust immunity and you could get it again.”

She adds that those who are immunosuppressed because of medication or illness, such as cancer or HIV, sometimes develop prolonged, repeated, or chronic zoster infections. “That's why it's critical for people to get immunized before they get old, sick, or start immunosuppressive medication,” she says.

Duration of Shingles

Pain, itch, or tingling, along with headache and other symptoms, may precede the shingles rash by several days, according to the CDC.

Once the rash emerges, new blisters form over the course of three to five days, and progressively dry out and crust over. The blisters usually heal in two to four weeks.
Despite treatment, an estimated 5 to 20 percent of shingles patients will continue to experience pain for weeks or even years after the blisters heal, notes MedlinePlus.

Those who are still feeling pain 90 or more days after the onset of the rash have a condition that’s called post-herpetic neuralgia or PHN.

(See the Complications section below for more info on PHN.)

Treatment and Medication Options for Shingles

There’s no cure for shingles, but if you get immediate treatment, it can help speed the healing process and reduce your risk of complications.

Medication Options

Your physician may prescribe an antiviral drug, such as Valtrex (valacyclovir), to treat the rash, in addition to other drugs if you are experiencing pain, notes the CDC.

Antivirals can help shorten the duration and severity of shingles and are most effective if you start them as quickly as possible after the rash appears.

Prescription or over-the-counter (OTC) pain medication may also bring relief. And if you’re 50 or older or over 18 and immunocompromised, you can receive a shingles vaccine once the disease has run its course.

Alternative and Complementary Therapies

Home remedies such as oatmeal baths can temporarily alleviate itching. Wet compresses and calamine lotion may also help soothe skin symptoms.

Learn More About Treating Shingles

Prevention of Shingles

The U.S. Food and Drug Administration (FDA) approved recombinant zoster vaccine, known as Shingrix, for adults ages 50 years old and older in 2017.

RELATED: CDC Committee Gives Green Light to Shingles Vaccine for Immunocompromised Adults

In July 2021, the FDA also approved Shingrix for adults ages 18 years old and older who are or will be at increased risk of herpes zoster because of immunodeficiency or immunosuppression caused by disease or therapy. In October 2021, the CDC's Advisory Committee on Immunization Practices (ACIP) also voted to recommend Shingrix in adults 19 years of age and older who are or will be immunodeficient or immunosuppressed because of disease or therapy.

Sales of an older, live vaccine, Zostavax, were discontinued in July 2020. Even if you’ve already had shingles, received Zostavax, or aren't sure whether you ever had chicken pox, you should get Shingrix, per the CDC.

Shingles can’t be passed between people, but the varicella zoster virus can spread to people who aren't immune to chicken pox — meaning those who have not been vaccinated against chicken pox or have not had the disease.

The varicella-zoster virus can spread from person to person through direct contact with the open sores of the shingles rash when blisters are present. It can also be spread by airborne droplets in people with a primary VZV infection.

Once infected for the first time, the person will develop chicken pox, not shingles.

If the rash is covered, the risk of a person with shingles spreading the virus to others is low.

But chicken pox can be dangerous for some groups of people, including premature or low birth weight infants, pregnant women who have never had chicken pox or the chicken pox vaccine, and anyone who has a weakened immune system.

So until your shingles blisters turn into scabs, you'll be able to pass the virus on to others and you should therefore avoid contact with those who could be harmed by catching chicken pox.

The following steps can help keep you from spreading the virus:

  • Keep the rash covered.
  • Avoid touching or scratching the rash.
  • Wash your hands often.

Complications of Shingles

Shingles can lead to several complications. The most common is long-term nerve pain called post-herpetic neuralgia (PHN), according to the CDC.

Up to 18 percent of people who get shingles will have PHN. The pain, which can be severe, is located in the areas where the shingles rash was, even after the rash disappears. PHN can last for months or even years. Risk of PHN increases with age, as does the severity and duration of the pain. It’s uncommon in people under 40.

Other complications can include:

  • Eye complications, including loss of vision, can occur
  • Bacterial infection of shingles lesions
  • Rare complications include the development of pneumonia, hearing problems, encephalitis (swelling of the brain), and death

Can Shingles Be Harmful During Pregnancy? 

While it's rare for pregnant women to develop shingles, if they do, it's unlikely to cause harm to the fetus, according to a review published October 2018 in the Journal of Obstetrics and Gynaecology.

Still, pregnant women who develop chicken pox can experience complications, including varicella pneumonia, a condition that can be fatal.

If a pregnant woman gets chicken pox during her first trimester or early in her second, there's a 0.4 to 2 percent risk that her infant will be born with congenital varicella syndrome (CVS), which can result in abnormalities in the brain, limbs, and eyes, as well as low birth weight, notes the CDC.

If a pregnant woman develops a varicella rash from five days before to two days after delivery, the newborn will be at risk for neonatal varicella.

Pregnant women who have been exposed to the virus may be given a varicella-zoster immune globulin (VZIG) injection to reduce the risk of complications to both mother and baby.

Research and Statistics: Who Gets Shingles?

Almost one out of every three people in the United States will develop shingles at some point, according to the CDC.

There are an estimated one million U.S. cases of shingles each year. About 1 out of 100 U.S. shingles cases occur in people age 60 or older.

In fact, about half of people over 80 have had shingles, notes MedlinePlus.

The chicken pox vaccine was introduced in 1995 and has reduced incidence of the virus by up to 85 percent. Theoretically, this should reduce the incidence of shingles as people who were vaccinated as children grow up, but it's too soon to know if this is the case.

Related Conditions and Causes of Shingles

As discussed above, the varicella-zoster virus causes the herpes zoster infection, which takes the form of chicken pox first. When your immune system fights off chicken pox, the virus stays in the body and can be reactivated, usually many years later, causing shingles.

If you've never had chicken pox, as a child or as an adult, and you're exposed to the virus — let's say you touch someone at the contagious, blister stage of shingles — transmission could occur and you'd get chicken pox.

If you haven't had chicken pox, you can't get shingles. But someone who has never had chicken pox or been vaccinated for it can contract chicken pox through close contact with someone who has shingles.

Resources We Love

Essential Organizations for Shingles Information

National Institute of Neurological Disorders and Stroke (NINDS)

Along with clear, comprehensive info about shingles — what it is and how it's treated — the NINDS provides updates on research looking into why the virus reactivates and efforts to better understand what leads to ongoing pain. The NINDS site also includes links to current clinical trials.

NIH National Library of Medicine Genetics Home Reference

Here you'll find a focus on the role of genetics in shingles. Research has suggested that certain genes may be associated with whether people develop shingles or post-herpetic neuropathy.

Neuropathy Commons

Shingles — including post-herpetic neuralgia and post-herpetic itch — is among the conditions that the Nerve Unit at Massachusetts General Hospital treats and studies. Their website, Neuropathy Commons, is dedicated to helping patients find neuropathy experts and resources in their area. In addition to a searchable database of neurologists who specialize in neuropathy, the site has links to patient stories and support groups.

Favorite Podcast for Shingles Info 

Shingles: What You Should Know About the Sequel to Chicken Pox

For an informative, accessible discussion on shingles — that you can listen to just about anywhere — check out an episode of this podcast from Cleveland Clinic's Health Essentials podcast.

Learn More About Additional Resources and Support for Shingles

Editorial Sources and Fact-Checking

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