Understanding What Causes Shingles to Activate
August 1, 2021
If you contract the chickenpox virus, also known as varicella-zoster, your illness will typically clear up in a week or two. However, this virus remains in your body even after you’ve recovered.
The virus lies dormant when your immune system is strong. But if something causes you to become immunocompromised, the virus can reactivate. This triggers shingles.
What is shingles?
Shingles, known by its medical name herpes zoster, presents as a painful rash. It typically shows up on only one side of your body.
According to the Centers for Disease Control and Prevention (CDC), the chance of getting shingles at some point in your life is 1 in 3.
When you first contract the varicella-zoster virus (VZV), you’ll get chickenpox. When you fight off this virus, your body creates immunity to it, so it’s very rare to get chickenpox a second time.
However, that doesn’t mean that your body rids itself of the virus entirely. Though a strong immune system will keep the virus inactive, it’s still there for the rest of your life.
If your immune system becomes weakened or compromised, it’s possible for this virus to reactivate. A painful shingles rash may result.
Prior to the development of the varicella vaccine, chickenpox was a common childhood illness. Most people were exposed to VZV in childhood and developed chickenpox in their younger years.
In fact, doctors once encouraged families to expose their kids to chickenpox at an early age — after age 10 or so, the disease can be much more severe. (You may remember “chickenpox parties,” where parents actively tried to get their children to contract the virus.)
Adults who come down with chickenpox can experience serious and even life-threatening complications like lung or brain infections.
These days, children and adults can receive the varicella vaccine. This weaker version of the live virus causes the body to launch an immune response so that it recognizes — and fights off — VZV in the future.
Getting a varicella vaccine appears to reduce the risk of shingles, but it isn’t a guarantee against them. Though weakened, the virus does continue to stay in your body, so it’s possible for it to reactivate and cause shingles. However, this is uncommon.
One study found that the rate of shingles infection was 78 percent lower in vaccinated children than unvaccinated children.
The varicella vaccine became available in 1995, so only time will tell its effects on the rates of shingles in older adults.
Why do some people get shingles?
If you’ve had chickenpox or gotten the varicella vaccine, you can develop shingles.
According to the CDC, over 99 percent of people in the United States born before 1980 have had chickenpox or been exposed to VZV.
The primary risk factor associated with getting shingles is a weakened immune system. When your immune system isn’t functioning properly, VZV can reactivate.
As you age, your immune system doesn’t fight off invaders as well. Older age is associated with a greater likelihood of health problems, including:
- a natural decline in immunity
- the use of immunosuppressant medications like chemotherapy, long-term corticosteroids, and anti-inflammatory medications
- certain diseases and conditions that damage your immune system, such as HIV and hypogammaglobulinemia
- autoimmune diseases that are treated with immune-suppressing drugs, such as rheumatoid arthritis, Crohn’s disease, and lupus
- procedures like bone marrow transplants and kidney transplants, which may require treatment with immunosuppressants afterward
Starting around age 50, your chance of getting shingles goes up. The severity of the disease and the risk of complications also increase with age.
It’s important to remember, too, that stress can negatively affect your immune system. There’s been some interest in whether stressful life circumstances could weaken the immune system, leading to a shingles infection. However, research is contradictory and doesn’t yet offer firm conclusions.
What are the symptoms of shingles?
Typically, shingles show up as a painful rash on an area of skin that is supplied by a single nerve. This area, regardless of its location on the body, is known as a dermatome. Look for these hallmarks of a shingles rash:
- A band of blistering lesions may cover red, inflamed skin, often on one side of the torso or face.
- Pain starts out feeling tingly or burning. Other common sensations include itching and numbness.
- The pain progresses in severity over several days.
- It feels like the pain is coming from the organs in your abdomen, like your heart, gallbladder, appendix, or kidneys.
- Sometimes (though rarely) people experience severe pain without a rash, known as zoster sine herpete.
Some people also have other, more general symptoms, like:
Shingles symptoms can last up to 4 weeks or longer.
How is shingles diagnosed?
To diagnose shingles, your doctor will ask you some questions about your symptoms. These may include:
- When did your symptoms start?
- Which symptom did you notice first?
- Are you experiencing pain?
- Where are you having pain?
- Have you had chickenpox?
- Have you had the chickenpox vaccine?
- Have you had the shingles vaccine?
They’ll also evaluate your rash, looking at its pattern, appearance, and location. Doctors can usually diagnose shingles by its distinctive rash and unique symptoms.
In rare cases, though, if your doctor is uncertain whether you have shingles, you may undergo a diagnostic test. Testing is more common for people with greater risk factors for complications, including:
- people with a weakened immune system
- pregnant people
To test for shingles, your doctor will use a swab to take a sample from a skin lesion. This will then be tested for VZV. A positive test indicates that you have shingles.
How is shingles treated?
Although there’s no cure for shingles, the good news is that it resolves on its own. Your doctor may recommend certain medications to alleviate pain or treat the infection.
Three antiviral medications are used to treat shingles:
Valacyclovir and famciclovir are taken three times per day. They’re usually preferred over acyclovir, which must be taken five times a day.
All three have a 7-day course if you have an uncomplicated case of shingles. If the shingles is complicated — if it’s affecting your eyes, for example — your doctor will prescribe the medication for longer than 7 days.
Antiviral medication can help:
- you recover faster
- limit the severity of your symptoms
- reduce your risk for complications
Antiviral medications offer the most benefit for people over 50 and those who are immunocompromised since these risk factors are associated with more persistent, severe shingles symptoms.
It’s best to start an antiviral while you’re still developing new skin lesions, usually within 72 hours of noticing your first symptom. Antivirals won’t be effective after your lesions have begun to crust over.
Some people may need to take a longer course of antiviral medications or even be treated in the hospital with antivirals. This is more likely if you have the following:
- a weakened immune system
- a severe case of shingles
- a high risk of complications
Some people experience shingles on the face. This can lead to serious complications, such as:
- hearing impairment
- brain swelling
Seek immediate medical attention if you think you have shingles on your face.
Mild shingles pain may improve with over-the-counter anti-inflammatory medications. Your doctor may recommend ibuprofen or acetaminophen or weak opioids, such as codeine or tramadol.
Stronger prescription opioid pain medication, such as hydrocodone, may be prescribed to treat moderate to severe shingles pain.
Another option is topical pain relievers, such as lidocaine. These are applied directly to your skin for relief. You can find topical pain relievers as ointments, creams, gels, sprays, or patches. Capsaicin, which comes in a cream or a patch, may also be helpful.
Other medications that may be used for relief include:
- calamine lotion to soothe itching
- antibiotics, if a bacterial infection develops around the rash
Is there a vaccine against shingles?
Shingix (recombinant zoster vaccine) is currently the only shingles vaccine available in the United States. It’s given to people over age 50.
Previously, an additional vaccine, Zostavax, was used, but it was phased out in the United States as of November 2020.
According to the CDC, two doses of Shingrix are over 90 percent effective at preventing shingles. You’ll retain at least 85 percent protection for 4 years after being vaccinated.
If you get shingles after being vaccinated, your symptoms will likely be less severe. You’ll also have a lower chance of developing postherpetic neuralgia — a complication where pain remains even after a shingles rash goes away.
What is the outlook for people with shingles?
Shingles usually follows a pattern of development. It typically progresses with the following symptoms:
- First, you may notice a tingling or burning sensation in your skin.
- One to 5 days later (or concurrent with the initial pain) a rash appears as small red spots.
- Fluid-filled blisters develop a few days later.
- After 7 to 10 days, the lesions crust over.
- The rash disappears over the next 2 to 4 weeks.
In some cases, pain may persist for several months or even years after the rash has disappeared. This complication, known as postherpetic neuralgia (PHN), can be severe enough to affect your quality of life.
Certain antiseizure medications can help manage the pain. Gabapentin and pregabalin are two that are commonly used.
It’s unlikely to get shingles more than once — but it’s possible. That’s why it’s recommended to get the shingles vaccine at age 50 and older, even if you’ve already had the disease. Getting shingles three times is extremely rare.
The bottom line
Shingles occur when the varicella-zoster virus is reactivated due to a weakened immune system. This can create a painful, blistering rash. The risk of getting shingles goes up with age, with an increased likelihood after age 50.
Shingles often don’t require treatment to make them go away, but some antiviral medications can help you recover faster and reduce your risk for complications.
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