What Is Chickenpox? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Medically Reviewed

Chickenpox, also known as varicella, is a viral infection that causes a rash that can spread over the entire body.

The rash starts as small, red spots and progresses to itchy, fluid-filled blisters.

These blisters eventually form a scab and heal, typically within a week or two.

Chickenpox is highly contagious and can spread quickly from an infected person to others who haven’t had the disease or been vaccinated against it.

While it usually affects children, chickenpox can also spread to adults who haven’t previously had the infection or the?chickenpox vaccine. Adolescents and adults are at higher risk for complications from chickenpox.

Before vaccination for chickenpox became routine in the United States, nearly everyone got chickenpox before adulthood. Since that time, cases of chickenpox and related hospitalizations have dropped dramatically.

While you can reduce your risk of catching chickenpox by avoiding contact with people known to be infected, the most effective way to prevent the disease is to get vaccinated.

If you suspect that you or your child has chickenpox, it’s a good idea to see a doctor. Your doctor can make a diagnosis and prescribe any necessary treatments.

Signs and Symptoms of Chickenpox

The main sign of chickenpox is a rash that turns into itchy, fluid-filled blisters.

This rash may start on the chest, back, or face before spreading all over the body.

After about a week, chickenpox blisters typically develop a crust and turn into scabs.

Other common symptoms associated with chickenpox include:

  • Fever
  • Fatigue
  • Headache
  • Reduced appetite

These symptoms may start a day or two before the rash develops. If you develop these symptoms and know that you’ve been exposed to chickenpox, it’s a good idea to stay home to avoid infecting others.

Learn More About Signs and Symptoms of Chickenpox

Causes and Risk Factors of Chickenpox

Chickenpox is caused by a virus called the varicella-zoster virus.

The disease spreads two ways:

  • By breathing in air droplets containing the chickenpox virus (from a person with chickenpox who coughs or sneezes)
  • Through direct contact with a chickenpox rash

You’re at high risk for chickenpox in these situations only if you’ve never had the disease or if you haven’t been vaccinated for it. Having the disease or getting vaccinated usually gives you immunity for life.

Most people get chickenpox through close contact with someone else who has the infection.

Chickenpox is contagious starting one to two days before a rash develops until all the blisters have crusted or turned into scabs. If the lesions do not turn into scabs, you are considered contagious until no new lesions have developed for 24 hours.

It’s also possible to get chickenpox from someone with shingles (herpes zoster), a viral infection that occurs when the chickenpox virus, which remains dormant (inactive) in the body after the illness has resolved, reactivates later in life, causing a blistering rash that can be extremely painful.

In the rare situation that you’ve been vaccinated for chickenpox but still get the disease, you can pass on your infection to other people — despite the likelihood that your symptoms will be mild.

There have been cases in which someone gets chickenpox more than once, but this is extremely rare.

Risk Factors

While serious complications of chickenpox are rare in healthy people, it’s possible for the disease to cause more dangerous secondary infections, brain infection or swelling, or even death.

Infants, adolescents, adults, pregnant women, and people with a weakened immune system due to illness or medications are at highest risk for chickenpox complications.

How Is Chickenpox Diagnosed?

The rash caused by chickenpox is usually enough for a doctor to diagnose it.

If there is any doubt about what is causing your rash, your doctor may conduct laboratory tests, including blood tests or a culture of lesion samples.

Prognosis of Chickenpox

Chickenpox is typically mild in healthy children.

The chickenpox vaccine also prevents almost all severe illness associated with the disease. If you or your child develops chickenpox after being vaccinated, it is likely to be a mild illness.

Duration of Chickenpox

Once you’re exposed to the chickenpox virus, it generally takes 10 to 21 days for you to develop a rash or any other symptoms.

The itchy rash that chickenpox causes usually lasts 5 to 10 days.

It typically takes about a week for all of the blisters to turn into scabs.

While the symptoms of chickenpox mostly clear up within a week or two, the virus itself stays in a person’s body for the rest of their life. For the most part, the virus remains dormant.

Treatment and Medication Options for Chickenpox

For most mild cases of chickenpox, resting, staying home, and employing some home remedies or over-the-counter products to ease the itching and discomfort are all that’s needed.

Adults and children at risk of complications may be prescribed antiviral drugs to reduce the severity and duration of chickenpox symptoms.

Children and teenagers should never be given aspirin?while they have chickenpox. Doing so raises the risk of developing Reye's syndrome, a serious disease that causes swelling of the brain and liver. Also talk to your doctor before taking any nonsteroidal anti-inflammatory drugs such as ibuprofen (Advil, Motrin) while you have chickenpox, or giving them to a child or teenager with chickenpox, as some studies have linked it to skin infections or tissue damage.

Medication Options

Most of the time, no medications are needed to treat chickenpox. If you or your child has severe itching, talk to your doctor about taking an antihistamine to help control it.

If you or your child has a fever due to chickenpox, taking acetaminophen (Tylenol) can help lower it.

For people with an elevated risk of complications from chickenpox, doctors often prescribe an antiviral drug, such as acyclovir (Zovirax, Sitavig).

Other antiviral drugs that may be options for some people include valacyclovir (Valtrex) and famciclovir (Famvir).

In some cases, your doctor may recommend getting the chickenpox vaccine within three to five days after you've been exposed to the virus, to prevent the disease or reduce its severity.

Alternative and Complementary Therapies

For most people, the only treatments needed for chickenpox are measures to relieve discomfort and help prevent bacterial skin infections. There are a couple tried-and-true home remedies:

A cool bath with added baking soda, aluminum acetate, uncooked oatmeal, or a colloidal oatmeal preparation may help relieve itching from chickenpox.

A wet compress — soaking a towel with cold water, placing it over an ice pack if desired, and holding or wrapping it against the skin — may also help relieve itching.

Learn More About Treatment for Chickenpox: Medication, Alternative and Complementary Therapies, and More

Prevention of Chickenpox

Getting the chickenpox vaccine is the best way to prevent chickenpox. This vaccine is recommended for people who have never had chickenpox.

Two doses of the chickenpox vaccine are needed for effective protection. Most people who receive the vaccine will never develop chickenpox, but those who do tend to have very mild symptoms such as red spots without blisters and little to no fever.

If you haven’t had chickenpox or the vaccine, avoid contact with anyone known to have chickenpox. Talk to your doctor if you believe you may have been exposed to someone with chickenpox in this situation.

Learn More About the Chickenpox Vaccine

Complications of Chickenpox

Complications from chickenpox are uncommon in healthy people and range from mild secondary skin infections to life-threatening brain swelling.

Among the possible complications of chickenpox:

  • Bacterial infection (usually affects skin and soft tissues in children)
  • Pneumonia?(lung infection)
  • Brain infection or swelling (encephalitis or cerebellar ataxia)
  • Dehydration
  • Bleeding problems
  • Sepsis?(bloodstream infections)
  • Death

The people at highest risk of developing serious complications include infants, teenagers, adults, pregnant women, and people with an impaired immune system due to illness or medications, including people with HIV/AIDS or cancer, people who have had transplants, and people on chemotherapy, immunosuppressive medications, or long-term use of steroids. But even healthy children can develop complications of chickenpox.

While some chickenpox complications are avoidable — for example, not scratching chickenpox blisters reduces the likelihood of skin infections — some are harder to prevent.

The best way to avoid chickenpox complications is to see a doctor for diagnosis and treatment advice if you or your child develops symptoms of chickenpox.

If a pregnant woman gets chickenpox early in her pregnancy, this can cause problems in her newborn, including:

  • Low birth weight
  • Limb abnormalities

In these cases, the newborn won’t actually be born with chickenpox. But if a woman develops chickenpox right before or after giving birth, it can cause a severe, life-threatening infection.

Learn More About the Complications of Chickenpox: How It Affects Your Body in the Short and Long Term

Research and Statistics: How Many People Get Chickenpox?

Before the chickenpox vaccine was introduced in 1995, about 90 percent of children got chickenpox by age 15.

In the early 1990s, there were about 4 million cases of chickenpox in the United States each year, resulting in 100 to 150 deaths annually.

Since the chickenpox vaccine was introduced, cases of chickenpox, along with hospitalizations and deaths, have dropped by over 90 percent.

While the chickenpox vaccine doesn’t prevent all cases of the disease, experts at the Centers for Disease Control and Prevention (CDC) estimate that about 98 percent of people who get both recommended doses will receive complete protection.

BIPOC Communities and Chickenpox

There’s little evidence to suggest that the risk of getting chickenpox is different for any racial or ethnic groups, including Black, Indigenous, and People of Color (BIPOC) populations, in the United States.

According to the U.S. Department of Health and Human Services Office of Minority Health, in the United States, non-Hispanic Black children ages 19 to 35 months old received the chickenpox vaccine at almost the same rate as non-Hispanic white children in 2017 — 89.3 percent for Black children versus 90.3 percent for white children.

However, there is some evidence that among older adults, people in BIPOC communities are less likely to get the shingles vaccine. In 2019, the CDC reported that 26.1 percent of adults age 50 and older had received a shingles vaccination. Non-Hispanic white adults (29.3 percent) were more likely than non-Hispanic Asian (22.9 percent), non-Hispanic Black (17.9 percent), and Hispanic (15.1 percent) adults to have received a shingles vaccination.

Related Conditions

The chickenpox virus is a close relative of herpes simplex viruses, which cause both?cold sores?and?genital herpes.

However, herpes simplex viruses do not cause chickenpox, and varicella-zoster virus does not cause the sores typical of herpes simplex infections.

In everyone who develops chickenpox, once the infection has passed, the chickenpox virus remains dormant in the body. But the virus can reactivate later in life, causing shingles.

Shingles is marked by a painful rash, usually on one side of the body. It can also occur on the face.

In addition to the rash — which may form blisters that itch, similar to chickenpox — shingles may cause fever, headache, chills, and upset stomach.

Certain eligible people can greatly reduce their risk of getting shingles by getting Shingrix, the FDA-approved?shingles vaccine. Shingrix, a two-dose vaccine, is recommended for all people who are 50 or older, and those 18 or older whose immune system is weakened or could become weakened by illness or treatment.

The risk for shingles increases with age, so it’s particularly important for older adults to be vaccinated.

Learn More About Chickenpox in Adults

Resources We Love

Need more information on chickenpox? These organizations can help.

Mayo Clinic

The experts at the Mayo Clinic offer an in-depth discussion of chickenpox and its possible complications.

Centers for Disease Control and Prevention

Parents can learn more about the chickenpox vaccine at the CDC website, including why getting the vaccine is a better idea than allowing children to catch the virus naturally.

Editorial Sources and Fact-Checking

Chickenpox.?Mayo Clinic. May 8, 2021.

Chickenpox (Varicella): About Chickenpox.?Centers for Disease Control and Prevention. April 28, 2021.

Chickenpox (Varicella): Signs and Symptoms.?Centers for Disease Control and Prevention. April 28, 2021.

Chickenpox (Varicella): Transmission.?Centers for Disease Control and Prevention. April 28, 2021.

Chickenpox (Varicella): Complications.?Centers for Disease Control and Prevention. April 28, 2021.

Chickenpox (Varicella). Merck Manual. September 2021.

Chickenpox (Varicella): Prevention and Treatment.?Centers for Disease Control and Prevention. April 28, 2021.

QuickStats: Percentage of Adults Aged ≥50 Years Who Ever Received a Shingles Vaccination, by Race and Hispanic Origin and Sex — National Health Interview Survey, United States, 2019.?Morbidity and Mortality Weekly Report. June 17, 2021.

Immunizations and African Americans.?U.S. Department of Health and Human Services Office of Minority Health. December 14, 2020.

Chickenpox.?New World Encyclopedia.

Shingles (Herpes Zoster): Signs and Symptoms.?Centers for Disease Control and Prevention. July 1, 2019.

Shingles (Herpes Zoster):?Clinical Considerations for Use of Recombinant Zoster Vaccine (RZV, Shingrix) in Immunocompromised Adults Aged ≥19 Years.?Centers for Disease Control and Prevention. January 20, 2022.

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