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 for 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 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 of the onset of the rash. Children should stay home and away from other children until all of the blisters have scabbed over. It is important that people who are infected avoid those with weak immune systems, such as those with organ transplants, HIV, or those 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 to children.

Most people who have had chickenpox will be immune to the disease for the rest of their lives. However, the virus remains inactive in nerve tissue and may reactivate later in life causing 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 weak immune systems. However, each person may experience symptoms differently. Symptoms may include:

• Fatigue and irritability one to two days before the rash begins
• 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 crops. It starts as flat red spots and progresses to raised red bumps that then become blisters.
• Feeling ill
• Decreased appetite

The initial symptoms of chickenpox may resemble other infections. Once the skin rash and blisters happen, it is usually obvious to a healthcare provider that it is chickenpox. If a person who has been vaccinated against the disease is exposed, he or she 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 unique. Diagnosis can usually be made on the appearance of the rash and a history of exposure.

How is chickenpox treated?

Specific treatment for chickenpox will be determined by your healthcare provider based on:

• Your overall health and medical history
• Extent of the condition
• Your tolerance for specific medicines, procedures, or therapies
• Expectations for the course of the condition
• Your opinion or preference

Treatment for chickenpox may include:

• Acetaminophen (to reduce fever). Children with chickenpox should NEVER be given aspirin. 
• Skin lotion (to relieve itchiness)
• Antiviral drugs (for severe cases)
• Bed rest
• Drinking plenty of fluids (to prevent dehydration)
• Cool baths with baking soda (to relieve itching)

Children should not scratch the blisters because it could lead to secondary bacterial infections. Keep fingernails short to decrease the likelihood of scratching.

What are the complications of chickenpox?

Complications can happen from chickenpox. They are more common in adults and people with weak immune systems. Complications may include:

• Secondary bacterial infections
• Pneumonia (lung infections)
• Encephalitis (inflammation of the brain)
• Cerebellar ataxia (defective muscular coordination)
• Transverse myelitis (inflammation along the spinal cord)
• Reye syndrome. This is a serious condition marked by a group of symptoms that may affect all major systems or organs. Do not give aspirin to children with chickenpox. It increases the risk for Reye syndrome.
• Death

When should I call my healthcare provider?

If your symptoms get worse or you have new symptoms, call your healthcare provider. You should tell your provider as quickly as possible if you get these symptoms:

• A fever that lasts longer than 4 days or goes above 102°F (38.8°C)
• The rash becomes more red or warm and tender, and has pus
• A change in mental status, such as confusion or extreme sleepiness
• Having problems walking
• Stiff neck
• Having 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 prevent chickenpox.
• Symptoms are usually mild in children. They may be life-threatening to adults and people of any age with weak immune systems.
• The rash of chickenpox is unique and the diagnosis can usually be made on the appearance of the rash and a history of exposure.
• Treatment helps reduce fever and itchiness of rash. Children with chickenpox should NEVER be given aspirin.

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.
• 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.