Herpes zoster, more commonly known as shingles, is a painful skin rash that often blisters.
The disease is caused by the same virus that causes chickenpox. Anyone who has had chickenpox can get shingles.
Close up of zoster blisters
What causes shingles?
The virus that causes chickenpox, the varicella zoster virus, stays in the body after chickenpox clears. If that virus gets reactivated (wakes up), it causes shingles.
It is not clear what reactivates the virus, but a weakened immune system seems to play a role. The immune system naturally weakens with age, and people who are 50 or older have a higher risk than others of getting shingles.
Other factors that can weaken the immune system and increase your risk of shingles include:
- An illness, a serious injury or stressful event.
- HIV or AIDS.
- Taking medicine that weakens the immune system, such as those taken after organ transplantation.
- Chemotherapy or radiation treatments for cancer.
Genes also may play a role, as having a close blood relative who has had shingles seems to increase your risk. Although you cannot catch shingles from your relatives, they may pass down genes that predispose you to the disease.
IS SHINGLES CONTAGIOUS?
While you cannot catch shingles from someone who has shingles, you can catch chickenpox from someone with shingles if you have not had the disease or the vaccine.
The only way to catch the varicella zoster virus from someone who has shingles is by touching fluid from a broken shingles blister.
This makes shingles much less contagious than chickenpox. If you have shingles, however, you are contagious for as long as you have blisters.
To prevent the virus from spreading, you should cover your blisters, avoid touching them and wash your hands often. You also should avoid contact with those for whom catching the virus could be dangerous, including pregnant women and babies less than 12 months old.
WHAT ARE THE SIGNS AND SYMPTOMS OF SHINGLES?
You may experience warning signs one to five days before the shingles rash appears. Your skin may burn, itch, tingle or feel extremely sensitive. This sensation usually affects a small area on one side of the body, but it can also wrap around the front and back on that side. Some people with shingles also develop flu-like symptoms, including chills, fever, headache, and feeling tired and run-down.
When the shingles rash appears, it usually forms on one side of the face or body and lasts two to four weeks. This rash tends to be less itchy but more painful than chickenpox. The affected area also can develop blisters, which may turn yellow or bloody before they scab and heal. Scarring may also occur.
CAN SHINGLES CAUSE OTHER HEALTH PROBLEMS?
Although shingles usually clears within a few weeks, it may cause complications that can last for months or even years. Possible complications include:
Post-herpetic neuralgia. This condition, which develops after the shingles rash and blisters clear, is the most common complication. It can cause pain, numbness, itching and tingling, which may be severe. Other symptoms of this condition include feeling tired and run-down, poor appetite, and trouble sleeping. People older than 60 are most likely to develop post-herpetic neuralgia.
Eye problems. When shingles affects the eye, it is called ocular shingles or herpes zoster opthalmicus. Symptoms of this condition include sensitivity to light, blurry vision and the feeling of a foreign object in the eye. Without treatment, this complication can lead to glaucoma, scarring and even blindness. People who have shingles in the eye also have an increased risk of stroke. If you develop shingles in or near your eye, or even on the tip of your nose, see a doctor as soon as possible to prevent possible loss of eyesight and other problems.
Infection. Warning signs of a skin infection include pain and redness. If you experience these symptoms after having shingles, see a board-certified dermatologist. You may need an antibiotic. If left untreated, a skin infection can cause scarring.
HOW IS SHINGLES DIAGNOSED?
A board-certified dermatologist can diagnose shingles by examining your skin. The doctor may gently scrape the blisters on your skin and look under the microscope to confirm the diagnosis while you are in the office. He or she may also take a swab of your skin and send it for a diagnostic test. These tests are important because other skin conditions, which are treated differently, can look similar to shingles.
HOW IS SHINGLES TREATED?
Although shingles can clear on its own in a few weeks, dermatologists strongly recommend treatment, which can reduce your risk of complications. If you see a doctor within 72 hours of getting the rash, you can get an antiviral medicine, such as famciclovir, valacyclovir or acyclovir, which can reduce the disease’s pain and severity, as well as the amount of time the disease lasts.
Other treatments may include:
- Pain relievers. If your pain is severe, prescription painkillers may be necessary.
- Nerve inflammation reduction medications. These medications, such as gabapentin, can help to reduce your risk of post-herpetic neuralgia. These medications are most effective when taken with antiviral medications.
- Nerve blocks. These injections contain anesthetic, and sometimes corticosteroids, to treat severe pain from post-herpetic neuralgia.
- Corticosteroid pills. Your dermatologist may recommend that you take these along with your antiviral medicine to reduce pain and swelling. This treatment is not appropriate for everyone, as it can cause the rash to spread.
Your dermatologist also may recommend the following tips to relieve pain and itching:
- Cool the rash with ice packs, a cool wet cloth or cool baths.
- Apply plain petroleum jelly to the blisters.
- Cover the rash with loose, nonstick, sterile bandages.
- Wear loose cotton clothes around the body parts that hurt.
After the rash clears, your dermatologist may prescribe other medications to treat the pain. These may include antidepressants, anesthetic creams and patches, or anti-seizure medicines. Talk to your doctor about the potential side effects of these medications.
CAN SHINGLES BE PREVENTED?
If you are 50 or older and have had chickenpox, your dermatologist may recommend that you get a shingles vaccine. The U.S. Food and Drug Administration has approved two vaccines to reduce the risk of getting shingles. These vaccines also can reduce your risk of developing complications.
These vaccines are not recommended for everyone. Before getting a shingles vaccine, be sure to tell your doctor about all of the medications you take, as well as any allergies and medical conditions you have, including skin diseases like eczema.
The shingles vaccine does not prevent chickenpox. Another vaccine is available to prevent chickenpox.
A board-certified dermatologist is a medical doctor who specializes in the diagnosis and medical, surgical and cosmetic treatment of skin, hair and nail conditions. To learn more about shingles or to find a board-certified dermatologist in your area, visit aad.org/shingles or call toll-free (888) 462-DERM (3376).
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Copyright © by the American Academy of Dermatology and the American Academy of Dermatology Association.
Images used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides
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