If you’ve had chickenpox, then you are at risk for shingles, a disease characterized by a painful skin rash. That’s because even after your body clears away the itchy chickenpox rash, the virus that caused chickenpox lingers in your body. During this period (which may last for years or decades), the virus does not cause any symptoms. And for many people, the virus remains dormant and never causes any problems. But for some, the virus can reactivate and cause shingles.

If you get shingles, you’re far from alone. In the U.S., there are an estimated 1.2 million cases every year, and according to the Centers for Disease Control and Prevention (CDC), about three out of ten people will get shingles at some point in their lifetime.

While shingles can cause severe pain that can make sleep difficult and get in the way of everyday activities, treatments are available that can relieve symptoms and shorten its duration. What’s more, shingles can be prevented with a vaccine.

“Shingles vaccines are widely available and very effective, so the best way to protect yourself is to get a vaccine,” says Yale Medicine dermatologist Jeffrey Cohen, MD. “If you do have shingles, treatment can help with the pain and discomfort—and help your skin heal. This can also prevent pain that can come after shingles resolves, called post-herpetic neuralgia.”

Shingles is a painful skin rash caused by infection by the varicella-zoster virus (VZV), the same virus that causes chickenpox. Shingles only affects people who have had chickenpox or received a chickenpox vaccination. After a person recovers from chickenpox, VZV remains in certain nerves in the body in an inactive state. Sometimes after getting over the chickenpox (usually years later), the virus reactivates, migrates along the nerves to the skin, and causes a blistering rash known as shingles.

As for chickenpox vaccination, it protects against chickenpox by introducing a strain of VZV into the body that, like a natural infection, can remain dormant in nerves and reactivate years later, causing shingles. The chances of getting shingles, however, is higher among people who have been naturally infected than among those who have received a chickenpox vaccination.

Doctors do not know exactly what causes the virus to reactivate in some people but not others. There is evidence, though, that this is more likely to occur in people who have a weakened immune system. Various medical conditions and medications can weaken the immune system and reduce its ability to fight off viruses. Among others, these include conditions like cancer, HIV infection and AIDS, having had a bone marrow or organ transplantation, and medications such as chemotherapy and corticosteroids. The immune system also declines with increasing age, and while shingles can affect people of any age, it is most common in those over 50.

Often, the first sign of shingles is a feeling of pain, tingling, burning, or itching along a band of skin on the torso or face. Other early signs include headache, chills, fever, or an upset stomach.

One to three days later, a painful rash develops. The rash usually affects a band of skin on only one side of the body (right or left), though in some cases, for instance, among immunocompromised people, it is more widespread. The rash most commonly develops on the chest, abdomen, back, or face, but it can also affect other areas of the body.

The rash begins as flat or raised red spots. Over the course of one or two days, they become fluid-filled blisters. New blisters may continue to form for several days. The rash is often painful—sometimes severely so—and may have a burning or itching sensation and be sensitive to touch. About three to five days after the blisters form, they begin to crust over, and in most cases, the rash clears up within two to four weeks. After the rash has gone away, however, some people may be left with scarring or an area of darkened skin.

• Postherpetic neuralgia (PHN). In about 10 to 18% of cases, after recovering from the shingles rash, people continue to have pain in the area of skin that was involved. Known as postherpetic neuralgia, this is the most common complication. It may last for weeks to (less commonly) years.
• Eye complications. Shingles can affect eyes. A rash on the tip or side of the nose is often a sign of eye involvement. It can cause vision problems, including vision loss.
• Ear complications. Shingles can also affect the ears, causing pain, ringing, weakness, or paralysis of facial muscles, and hearing loss.
• Other complications. In rare cases, shingles can cause other complications including bacterial infection, meningitis, and stroke. 

The blistering rash associated with shingles contains infectious virus. This means that people who have never had chickenpox or who have not been fully vaccinated against it could contract the virus from someone with shingles and end up with chickenpox. This can happen through physical contact with skin blisters or, less commonly, through airborne transmission, by inhaling virus-containing aerosols.

Because of this, people who have shingles should stay away from anyone who has never had chickenpox or has not been vaccinated against it. It is particularly important to stay away from anyone who is pregnant. People can also reduce the risk of spreading the virus by covering their blisters. When all the blisters have dried and crusted over, the disease is no longer contagious.

To diagnose shingles, your doctor will review your medical history, perform a physical exam, and, in some cases, run one or more diagnostic tests.

Your doctor will ask about your symptoms and carry out a physical exam to look at your skin. If a rash has not yet developed, your doctor may still be able to diagnose shingles based on your symptoms. For instance, if a strip or band of skin on one side of your body feels tingly, itchy, or painful, your doctor may suspect shingles. If you have a rash, your doctor will examine it for characteristic signs of shingles and to rule out other diseases. Usually, a medical history and physical exam are enough to make a diagnosis. Sometimes, though, further testing is necessary to confirm diagnosis. Your doctor may swab your skin blisters to collect fluid for laboratory analysis. In some cases, he or she may biopsy a tiny area of the rash for testing.

The Shringrix vaccine can protect against shingles and complications from the disease. The CDC recommends that all healthy adults age 50 or older, whether or not they’ve had chickenpox, get two doses of the vaccine. Because people can get shingles more than once, vaccination is recommended even for people who have already had the disease.

Over-the-counter medications like acetaminophen, aspirin, ibuprofen, or naproxen can help to relieve pain caused by shingles. If the pain is severe or does not respond to over-the-counter remedies, a doctor can prescribe a stronger pain reliever.

Other treatments include:

• Antiviral drugs. These medications fight infections caused by viruses and for shingles, they can help the skin rash clear up faster and lessen symptom severity. Antiviral drugs work best when they are initiated within three days of the appearance of skin rash, but they may be used after this three-day window if new blisters are still forming.
• Steroids. Oral corticosteroids like prednisone can help to reduce inflammation and pain. They may be used in combination with an antiviral mediation.

People whose eyes are affected by shingles are usually referred to an eye doctor for treatment. 

While there is no cure for shingles, the vast majority of people who get the disease fully recover without complications within two to four weeks. For some, in particular, in those whose immune systems are suppressed by another medical condition or medication, the disease may be more severe, and it may take longer for the rash to clear up. That’s why prevention is key: The CDC recommends that all healthy adults aged 50 or older, whether or not they’ve had chickenpox, get two doses of the Shringrix vaccine.

“The key to appropriate treatment of shingles is rapid diagnosis,” says Dr. Cohen. “Yale Medicine dermatologists are experienced at recognizing the different presentations of shingles, performing any necessary tests to confirm the diagnosis, and designing effective treatment plans.”