Shingles (herpes zoster) is a viral infection of the nerve roots. It causes pain and often causes a rash on one side of the body, the left or right.
The rash appears in a band, a strip, or a small area. Shingles is most common in older adults and people who have weak immune systems because of stress, injury, certain medicines, or other reasons. Most people who get shingles will get better and will not get it again.
What causes shingles?
Shingles is a reactivation of the varicella-zoster virus, a type of herpes virus that causes chickenpox. After you have had chickenpox, the virus lies inactive in your nerve roots and remains inactive until, in some people, it flares up again. When the virus becomes active again, you get shingles instead of chickenpox.
Anyone who has had even a mild case of chickenpox can get shingles. People who have a weak immune system are vulnerable to reactivation of the virus that causes shingles. Many factors can weaken your immune system, including aging, injury, and illness.
Some medicines slow down the immune system. For example, medicines that destroy cancer cells (chemotherapy) can interfere with the immune system.
Exposure to shingles will not cause you to get shingles. But if you have not had chickenpox and you are exposed to shingles, you can get chickenpox. Someone with shingles can potentially expose you to chickenpox if you come into contact with the fluid in the shingles rash blisters.
One study reports that the virus that causes shingles may be released into the air from shingles sores. Covering the shingles sores with a type of dressing that absorbs fluids and protects the sore (hydrocolloid dressing, such as DuoDerm) appears to effectively contain the virus.
You can’t catch shingles from someone else who has shingles.
When the virus that causes chickenpox reactivates, it causes shingles. Early symptoms of shingles include headache, sensitivity to light, and flu-like symptoms without a fever. You may then feel itching, tingling, or pain where a band, strip, or small area of rash may appear several days or weeks later.
A rash can appear anywhere on the body but will be on only one side of the body, the left or right. The rash will first form blisters, then scab over, and finally clear up over a few weeks. This band of pain and rash is the clearest sign of shingles.
The rash caused by shingles is more painful than itchy. The nerve roots that supply sensation to your skin run in pathways on each side of your body. When the virus becomes reactivated, it travels up the nerve roots to the area of skin supplied by those specific nerve roots.
This is why the rash can wrap around either the left or right side of your body, usually from the middle of your back toward your chest. It can also appear on your face around one eye. It is possible to have more than one area of rash on your body.
Shingles develops in stages:
Prodromal stage (before the rash appears)
- Pain, burning, tickling, tingling, and/or numbness occurs in the area around the affected nerves several days or weeks before a rash appears. The discomfort usually occurs on the chest or back, but it may occur on the abdomen, head, face, neck, or one arm or leg.
- Flu-like symptoms (usually without a fever), such as chills, stomachache, or diarrhea, may develop just before or along with the start of the rash.
- Swelling and tenderness of the lymph nodes may occur.
Active stage (rash and blisters appear)
- A band, strip, or small area of rash appears. It can appear anywhere on the body but will be on only one side of the body, the left or right. Blisters will form. Fluid inside the blister is clear at first but may become cloudy after 3 to 4 days. A few people won’t get a rash, or the rash will be mild.
- A rash may occur on the forehead, cheek, nose, and around one eye (herpes zoster ophthalmicus), which may threaten your sight unless you get prompt treatment.
- Pain, described as “piercing needles in the skin,” may accompany the skin rash.
- Blisters may break open, ooze, and crust over in about 5 days. The rash heals in about 2 to 4 weeks, although some scars may remain.
Postherpetic neuralgia (chronic pain stage)
- Postherpetic neuralgia is the most common complication of shingles. It lasts for at least 30 days and may continue for months to years. Symptoms are:
- Aching, burning, stabbing pain in the area of the earlier shingles rash.
- Persistent pain that may linger for years.
- Extreme sensitivity to touch.
- The pain associated with postherpetic neuralgia most commonly affects the forehead or chest, and it may make it difficult for the person to eat, sleep, and perform daily activities. It may also lead to depression.
Shingles may be confused with other conditions that cause similar symptoms of rash or pain, such as herpes simplex infection or appendicitis.
It’s possible that you could also feel dizzy or weak, or you could have long-term pain or a rash on your face, changes in your vision, changes in how well you can think, or a rash that spreads. If you have any of these problems from shingles, call your doctor right away.
How is shingles treated?
There is no cure for shingles, but treatment may help you get well sooner and prevent other problems. Call your doctor as soon as you think you may have shingles. The sooner you start treatment, the better it works. Treatment may include:
- Antiviral medicines, sometimes given with steroid medicines, to help you get well sooner and feel less pain.
- Medicines to help long-term pain. These include antidepressants, pain medicines, and skin creams.
Good home care can help you feel better faster. Take care of any skin sores, and keep them clean. Take your medicines as directed. And use over-the-counter pain medicines to relieve pain.
Avoid contact with people until the rash heals. While you have shingles, you can spread chickenpox to people who have never had chickenpox. Be extra careful to avoid people with weak immune systems and pregnant women and babies who have never had chickenpox.
Who gets shingles?
Anyone who has had chickenpox can get shingles. You have a greater chance of getting shingles if you:
- Are older than 50.
- Have an autoimmune disease that causes your immune system to attack your body’s own tissues.
- Have another health problem or stress that weakens the immune system.
If you have never had chickenpox, avoid touching someone who has shingles or chickenpox. If you are at least 60 years old, you can get a vaccine that may prevent shingles or make it less painful if you do get it.