What is chickenpox?

Chickenpox is a common childhood disease. It causes an itchy, blistering rash and is easily spread to others.

Until the varicella vaccine for chickenpox became available in 1995, the chickenpox infection was very common. Almost everyone had been infected as a child. Now a vaccine is available to help prevent chickenpox. Two doses of the vaccine are recommended for children, teens, and nonimmune adults.

What causes chickenpox?

The disease is caused by the varicella-zoster virus. It is easily passed from person to person through the air by coughing or sneezing, or by direct contact.

Who is at risk for chickenpox?

Any child or adult who has never had chickenpox or been vaccinated against it is at risk of getting the disease.

Chickenpox is passed from person to person through the air by coughing and sneezing, or by direct contact. It can also be spread by being exposed to the fluid from the blistering rash. Once you are exposed, symptoms usually appear within a couple of weeks. But it may take as few as 10 and as many as 21 days for the chickenpox to develop.

Chickenpox is contagious for 1 to 2 days before the rash starts and until the blisters have all dried and become scabs. The blisters usually dry and become scabs within 5 to 7 days after the rash starts. Have your children stay home and away from other children until there are no new blisters for 24 hours and all of the blisters have scabbed over. It's important that people who are infected stay away from people with a weak immune system. This includes people who have a transplanted organ or HIV, or who are getting cancer treatment.

Family members who have never had chickenpox have a high chance of becoming infected when another family member in the house is infected. The illness is often more severe in adults and pregnant women compared with children.

Most people who have had chickenpox will not get another case of the disease for the rest of their lives. But the virus stays in nerve tissue and may reactivate later in life. This illness is called shingles. Blood tests can confirm immunity to chickenpox in people who are unsure if they have had the disease.

What are the symptoms of chickenpox?

Symptoms are usually mild in children. But symptoms may be life-threatening to adults and people of any age with a weak immune system. Symptoms may be a bit different in each person. Symptoms may include:

• Tiredness (fatigue) and irritability 1 to 2 days before the rash starts

• Itchy rash on the trunk, face, scalp, under the armpits, on the upper arms and legs, and inside the mouth. The rash appears in several phases. It starts as flat red spots and turns into raised red bumps that then become blisters.

• Feeling ill

• Less appetite than normal

The first symptoms of chickenpox may look like other infections. Once the skin rash and blisters happen, it's usually clear to a healthcare provider that it is chickenpox. If you have been vaccinated against the disease and are exposed to it, you may get a milder illness with less severe rash and mild or no fever. Always talk with your healthcare provider for a diagnosis.

How is chickenpox diagnosed?

The rash of chickenpox is different from other rashes. Your healthcare provider will often make the diagnosis based on how the rash looks and your history of exposure.

How is chickenpox treated?

Treatment for chickenpox may include:

• Acetaminophen to reduce fever. NEVER give aspirin or products containing aspirin to children with chickenpox or any other viral infection. 

• Skin lotion to ease itching

• Antiviral medicines for teens and adults, pregnant women, and others at higher risk for complications. These medicines are also given to those who already have complications.

• Bed rest

• Drinking plenty of fluids to prevent dehydration

• Cool baths or compresses with baking soda to ease itching

Tell your children not to scratch the blisters. Scratching can cause secondary bacterial infections. Keep fingernails short to lower the likelihood of scratching.

What are possible complications of chickenpox?

Complications can happen from chickenpox. They are more common in adults, pregnant women, and people with a weak immune system. Complications may include:

• Secondary bacterial infections of the skin sores

• Lung infection (pneumonia)

• Inflammation of the brain (encephalitis)

• Problems with muscle coordination (cerebellar ataxia)

• Inflammation along the spinal cord (transverse myelitis)

• Infection in an unborn child or newborn

• Reye syndrome. This is a serious condition marked by a group of symptoms that may affect all major systems or organs. Never give aspirin or products containing aspirin to children with chickenpox or any other viral infection. It increases the risk for a serious condition called Reye syndrome.

• Death

When should I call my healthcare provider?

Call your healthcare provider right away at the first signs of the infection and if your symptoms get worse or you have new symptoms. Tell your provider as quickly as possible if you get these symptoms:

• Fever that lasts longer than 4 days or goes above 100.4°F (38°C), or as directed by your healthcare provider

• Rash becomes more red or warm and tender, and has pus

• Change in mental status, such as confusion or extreme sleepiness

• Problems walking

• Stiff neck

• Problems with breathing or a frequent cough

• Frequent vomiting

Key points about chickenpox

• Chickenpox is a common childhood illness. It is easily spread to others.

• There is a vaccine available to help prevent chickenpox.

• Symptoms are often mild in children. They may be life-threatening to adults and people of any age with a weak immune system.

• The rash of chickenpox is different from other rashes.

• Treatment helps reduce fever and the itchiness of rash. It may be used to prevent or treat complications of the disease. Never give aspirin or any product containing aspirin to children with chickenpox or any other viral infection.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are and when they should be reported.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.