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 was licensed in 1995, chickenpox infection was very common. Almost everyone had been infected as a child. Now a vaccine is available to 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 by direct contact or through the air by coughing or sneezing.

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 by direct contact or through the air by coughing and sneezing. 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 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 an transplated 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 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 callled shingles. Very rarely, a second case of chickenpox does happen. 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 to children with chickenpox. 
  • 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 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 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)
  • Reye syndrome. This is a serious condition marked by a group of symptoms that may affect all major systems or organs. Don't give aspirin to children with chickenpox. It increases the risk for Reye syndrome.
  • Death

Online Medical Reviewer: Barry Zingman MD

Online Medical Reviewer: Donna Freeborn PhD CNM FNP

Online Medical Reviewer: L Renee Watson MSN RN

Date Last Reviewed: 12/1/2018

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