If you had chickenpox as a kid, you no doubt remember it well: lying in bed with all those itchy red bumps while your mother chastised you for scratching.

The red spots and the itchiness eventually went away, but the disease left a lasting gift behind. The varicella-zoster virus that causes chickenpox goes dormant in your body, typically in the nerve tissue around your spinal cord and brain, according to the Mayo Clinic. For some people, it stays inactive; for others, it resurfaces and causes shingles.

What is shingles?

Shingles is a viral infection that triggers a painful rash. Though the rash can appear anywhere on your body, it most commonly shows up as a band wrapping around one side of your body.

According to WebMD, shingles symptoms happen in stages. Early on, you may have a headache, light sensitivity or flu-like symptoms.

As the illness gets worse, you may start to feel itching (reminiscent of your early chickenpox days), tingling or pain in a specific area. That's where a rash will probably arise a few days later. The rash then transforms into blisters, which eventually fill with fluid and turn crusty. The blisters take several weeks to heal and may cause scarring.

The rash can range from mild to severe in most people, while some don't get a rash at all. Other symptoms might include feeling dizzy or weak, vision changes, confusion and fever.

What triggers shingles

Not everyone who had chickenpox as a child will get shingles as an adult. Doctors are unsure what causes the virus to stay dormant in some people and why it "wakes up" in others.

It could be because stress, illness or aging makes the immune system weak and more susceptible to the virus. Shingles is more common in older adults and people who have a weakened immune system. That includes people with certain cancers like leukemia and lymphoma, as well as HIV, according to the Centers for Disease Control and Prevention (CDC).

Some medications may trigger the virus to become active again. Those include immunosuppressive drugs, such as steroids and drugs that are given after organ transplantation.

When it stirs, the virus only causes shingles; it can't cause the chickenpox again. About one in three Americans will get shingles in their lifetime, according to the CDC.

Is shingles contagious?

shingles infection on back A shingles rash typically starts with red bumps, and then the area transforms into blisters that ooze and crust over. (Photo: TopKatai/Shutterstock)

You can't pass shingles from one person to another. But the virus can spread from a person with an active shingles infection to cause chickenpox in someone who has never had chickenpox or who never received the vaccine, reports the CDC. The virus can be spread during the blister stage, through direct contact with the fluid from the blisters.

To avoid spreading the virus, the CDC suggests:

  • Cover the rash.
  • Avoid touching or scratching the rash.
  • Wash your hands often.
  • Until your rash has developed crusts, avoid contact with people with weakened immune systems, pregnant women who have never had chickenpox or the vaccine, and premature or low birth weight infants.

Treatment and prevention

If you think you have shingles, prescription antiviral drugs can help ease your symptoms and speed up healing. Your doctor also may suggest medicine for pain.

To lessen your chances of getting shingles, your doctor likely will recommend the shingles vaccine. It's approved for people starting at age 50, but the CDC recommends starting at age 60 when the risk for shingles and complications are the highest.

Until recently, the only varicella-zoster vaccine was Zostavax. But in late October 2017, the U.S. Food and Drug Administration approved the vaccine Shingrix. The Advisory Committee on Immunization Practices (ACIP), which advises the CDC, voted to recommend the vaccine to anyone over 50, and also voted to recommend it over Zostavax. It also said people who had already received the Zostavax vaccine should return to get the Shingrix injection.

Trials showed the new drug was more effective than the older vaccine in preventing the painful skin infection, as well as the nerve pain that can continue once the infection has cleared. Although Shingrix is shown to be more effective, it is associated with more side effects, such as fever and muscle pain, reports HealthDay.

Shingrix has not yet been officially endorsed by the CDC and is still more expensive than Zostavax because it's not yet covered by insurance.

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.