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

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

Anyone who’s had chickenpox 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.

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

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.

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:

• Chills
• Fever
• Headache
• Upset stomach

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

The varicella zoster virus — the virus that causes chickenpox 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 chickenpox, you can get shingles. After the chickenpox 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.

Risk Factors

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

• 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 and inflammatory bowel diseases, as well as drugs that are given to people who have undergone an organ transplant

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.

“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

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.

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 three features that distinguish it from conditions with similar symptoms: its flu-like onset, the severe pain that follows, and the fact that the pain and blisters are almost always on one side of the body.

Prognosis of Shingles

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

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 chickenpox or shingles, it boosts your immunity for the next decade or so, but if you were immunosuppressed when you contracted the chickenpox 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.

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

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 to reduce the risk of future recurrences.

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

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. While rare, it can also be spread by airborne droplets in people with a primary VZV infection, according to a case study.

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

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

But chickenpox can be dangerous for some groups of people, including premature or low birth weight infants, pregnant women who have never had chickenpox or the chickenpox 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 chickenpox.

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

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? 

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

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.

The chickenpox 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 still too soon to know if this is the case.

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

If you’ve never had chickenpox, 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 could get chickenpox.

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