What causes chickenpox?

Chickenpox is caused by the varicella-zoster virus. It can easily spread to people who haven't had chickenpox and haven't been vaccinated. The virus spreads when:

• You breathe in the virus from the air. This can happen when someone with chickenpox or shingles sneezes or coughs near you.

• You get the virus on your hands. This can happen if you touch someone’s chickenpox or shingles blisters.

A person with chickenpox can pass the virus on to others before they have any symptoms. This is one reason why chickenpox spreads so easily.

What are the symptoms of chickenpox?

Chickenpox is often a mild illness, especially in young children. But it can sometimes be serious enough to cause severe illness or even death. This is especially true for older adults and anyone who has a weakened immune system.

Chickenpox often starts with symptoms that feel like the flu, including:

• Fever.

• Headache.

• Sore throat.

• Feeling tired or unwell.

• Loss of appetite.

A day or two later, red spots appear on your body. This rash is often itchy. The red spots turn into small blisters. Then they scab over and go away. Blisters may also appear in your mouth or throat. A chickenpox rash often goes away within 2 weeks.

How is chickenpox treated?

Treatment for most children with chickenpox focuses on easing symptoms. These treatments may include:

• Over-the-counter pain medicines (such as acetaminophen). They can help with mild pain, especially if blisters are inside the mouth. Do not give aspirin to anyone younger than 20. It has been linked to Reye syndrome, a serious illness.

• Over-the-counter antihistamine medicines, such as diphenhydramine or loratadine. They can help ease itching.

• Skin treatments to ease itching. These include calamine lotion and oatmeal baths.

In most cases, your child's health care provider won't give a child antiviral medicine or antibiotics for chickenpox. These medicines don't shorten the illness or ease its symptoms.

Follow all directions for using medicines, especially when giving them to children. Contact your child's provider if you have any questions about using medicines safely.

Having chickenpox virus is risky for:

• People who are pregnant.

• Babies.

• Children older than 12.

• Adults.

• People with a weak immune system.

• People with certain long-term (chronic) skin or lung diseases.

For these people, treatment is aimed at helping the body fight the virus. It's likely to include antiviral medicine, either by mouth or through an IV (intravenous) line. This can help shorten the illness or make it less severe. This is especially true if you take this medicine very early in the illness.   

How can you prevent chickenpox?

The best way to prevent the spread of chickenpox is to make sure that you and your family are immune to it.

• Talk with your health care provider about getting the vaccine if you didn't have chickenpox as a child, or if you haven't had the vaccine.

• Make sure your children have all their vaccines on schedule.

Ask your provider about getting the vaccine if you've been exposed to the virus and haven't had the infection in the past or been vaccinated against it. This can prevent illness or make it less severe.

What are the possible complications of chickenpox?

Complications of chickenpox include:

• Skin infection. Scratching can allow bacteria to get into the blisters.

• Infection of the brain or spinal cord. This can cause severe headache, unsteady movements, severe sleepiness, seizures, or stroke.

• Lung infection (pneumonia). This causes a cough, shortness of breath, or chest pain.

When should you contact your doctor?

Contact your health care provider right away if:

• You have a fever of 100.4°F ( 38°C) or higher, or as directed by your provider.

• You have any of the complications listed above.

• You can't eat or drink because of painful sores in your mouth or throat.

• You can't keep fluids down.

• You don’t start to feel better after 5 to 7 days.