Chickenpox

Overview

Chickenpox is an illness caused by the varicella-zoster virus. It brings on an itchy rash with small fluid-filled blisters. The virus spreads easily to people who haven't had the disease or haven't gotten the chickenpox vaccine.

The chickenpox vaccine is a safe way to prevent this illness and the other health issues that can happen with it. Chickenpox used to be a widespread condition, but today the vaccine protects children from it.

Symptoms

The itchy rash from chickenpox appears 10 to 21 days after you're exposed to the varicella-zoster virus. The rash often lasts about 5 to 10 days. Other symptoms that may appear 1 to 2 days before the rash include:

• Fever.
• Not wanting to eat.
• Headache.
• Tiredness and a feeling of not being well.

Once the chickenpox rash appears, it goes through three phases:

• Raised bumps called papules, which break out over a few days.
• Small fluid-filled blisters called vesicles, which form in about one day and then break and leak.
• Crusts and scabs, which cover the broken blisters. The scabs most often fall off in 1 to 2 weeks.

New bumps keep showing up for several days. So you may have bumps, blisters and scabs at the same time. You can spread the virus to other people for up to 48 hours before the rash appears. And you can keep spreading it until all broken blisters have crusted over.

The condition is often mild in children with no other health issues. But for some children, the rash covers the whole body. Blisters may form in the throat and eyes. They also may form in the tissue that lines the anus, the vagina and the inside of the tube that carries urine out of the body, called the urethra.

When to see a doctor

If you think you or your child may have chickenpox, contact your healthcare professional's office. To keep from infecting people in the waiting room, tell the staff that you think you or your child may have chickenpox.

Causes

A virus called varicella-zoster causes chickenpox. The virus can spread through direct contact with the rash. You also can get it when a person with chickenpox coughs or sneezes and you breathe in the air droplets.

Risk factors

Not having had chickenpox or the chickenpox vaccine raises your risk of getting the virus.

Most people who have had chickenpox or have gotten the vaccine are immune to chickenpox. If you've been vaccinated and still get chickenpox, symptoms are often milder. You may have fewer blisters and mild or no fever. A few people can get chickenpox more than once, but this is rare.

Complications

Chickenpox is often mild. But it can be serious and lead to other health issues, including:

• Infection of the skin, soft tissues or bloodstream caused by bacteria.
• Dehydration, which is when the body does not have enough water and other fluids.
• Pneumonia, an illness in one or both lungs.
• Swelling of the brain, called encephalitis.
• Toxic shock syndrome, a dangerous complication caused by bacteria.
• Reye's syndrome, a condition that causes swelling in the brain and liver. This can happen in children and teens who take aspirin during chickenpox.

Who's at risk?

People who are at higher risk of chickenpox complications include:

• Newborns and infants born to people who haven't had chickenpox or the vaccine. This includes children under age 1 who have not yet had the vaccine.
• Adults.
• Pregnant people who haven't had chickenpox.
• People who have a condition that lowers their immune system response or take medicines that lower this response.

Chickenpox and pregnancy

Low birth weight and limb problems are more common in babies born to women who are infected with chickenpox early in their pregnancies. When a pregnant person catches chickenpox in the week before birth or within a couple of days after giving birth, the baby has a higher risk of getting a life-threatening infection.

If you're pregnant and not immune to chickenpox, talk to your health care provider about these risks.

Chickenpox and shingles

If you've had chickenpox, you're at risk of a complication called shingles. The varicella-zoster virus stays in your nerve cells after the chickenpox rash goes away. Years later, the virus can turn on again and cause shingles, a painful cluster of blisters. The virus is more likely to come back in older adults and people who have weakened immune systems.

The pain of shingles can last long after the blisters go away, and it can be serious. This lasting pain is called postherpetic neuralgia.

A vaccine against shingles is recommended for people age 50 and older. The vaccine, called Shingrix, also is an option for people age 19 or older with a weakened immune system because of illness or medical treatments. Get Shingrix even if you've already had shingles or you've had the older shingles vaccine called Zostavax.

There are other shingles vaccines people can get outside of the United States. If you need to get one, talk with your healthcare professional about how well they prevent shingles.

Prevention

To help prevent chickenpox, get two doses of the varicella vaccine. If you get chickenpox after having the vaccine, your symptoms may be much milder. The first dose is suggested around 12 months of age, and the second between ages 4 and 6 years.

Older children who haven't been vaccinated can catch up with two shots at least four weeks apart. This vaccine may be given alone or with the measles, mumps and rubella vaccines. That combined vaccine is called MMRV.

Some people shouldn't get the vaccine, or they should wait. Check with your healthcare professional about whether you should get the vaccine if you:

• Have a weakened immune system. This includes people who have HIV or take medicines that lower the immune system response.
• Are allergic to gelatin or the antibiotic neomycin.
• Have cancer or are getting cancer treatment with radiation or medicines.
• Recently got blood from a donor or other blood products.

Do not get the chickenpox vaccine if you're pregnant. If you want to get the vaccine before pregnancy, don't try to get pregnant until one month after you have the last dose of the vaccine.