Chickenpox Causes and Treatment

It used to be that getting chickenpox was a normal, even expected, part of childhood. Today, vaccination has reduced the number of chickenpox cases in the community. But it's important to know this serious childhood disease is still out there.

Tina Tan, MD, Attending Physician in Lurie Children's Division of Pediatric Infectious Diseases, explains what causes chickenpox and how doctors treat chickenpox symptoms.

What causes chickenpox?

The varicella-zoster virus (VZV) causes chickenpox. Exposure to this virus is the only way to get the illness. Humans are the only source of infection for this highly contagious virus,” Dr. Tan says.

What are the symptoms of chickenpox?

Children who have chickenpox may have a fever. They may also feel tired and have headaches. But the most obvious chickenpox symptom is an outbreak of groups of itchy red bumps (vesicular rash) on the skin all over the body. As the illness progresses, the bumps (lesions) fill with fluid, then burst and begin to crust. 

“The chickenpox rash usually appears in what we call crops,” Dr. Tan says. “As some lesions start to fade away, you may get more in a different area. The groups of lesions are in different stages of development.”

When is chickenpox contagious?

People infected with VZV can spread the virus during the early stage of chickenpox, about two days before the rash appears. They remain contagious until all the lesions are dry and crusted. 

Before crusting occurs, people nearby can breathe in virus particles from the lesions. They can also touch the lesion fluid and become infected with VZV.

According to Dr. Tan, crusting occurs in waves because lesions develop in different stages. That’s why it’s important to keep your child home until you’re sure they haven’t developed any new lesions. Lesions usually appear and crust within seven to 10 days from the onset of illness. Remember, a person with chickenpox is contagious until all lesions have crusted over.

How should you treat chickenpox?

There’s no treatment for the viral infection that causes chickenpox. But there are some things you can do to manage your child’s symptoms:

Control itching

Take steps to help your child feel less itchy and avoid spreading lesions to other parts of their body. You should:

• Have your child take a slightly warm or cool bath to make their skin feel better. You can add baking soda or colloidal oatmeal to the water to help relieve itching.
• Apply plain, nonantibiotic lotion to your child’s skin to help keep it moist. Be sure to wear gloves while you do this and wash your hands afterward to avoid spreading virus particles.
• Trim your child’s fingernails to discourage scratching. If their nails are long and they scratch, virus particles may become lodged under the nails. This can spread the virus.

Reduce fever

Use acetaminophen to help lower their temperature. It’s important to avoid aspirin and any medications containing aspirin. Aspirin can cause a life-threatening condition called Reye’s syndrome in children with viral illnesses like chickenpox.

Dr. Tan also says parents shouldn’t give ibuprofen to children with chickenpox. “Data suggests an association with the use of ibuprofen and the development of life-threatening group A strep infections of the skin in children with chickenpox,” she says.

Is there a way to prevent chickenpox?

The best way to prevent chickenpox is to get vaccinated. Doctors give the varicella (chickenpox) vaccine in two doses. Children should get the vaccine:

• At 12 to 15 months old (first dose)
• At 4 to 6 years old (second dose)

Adolescents, adults and older children who haven’t had chickenpox and are not vaccinated should also get the vaccine. Vaccinated people can still get chickenpox, but usually, symptoms will be mild. 

What should I do if I think my child has chickenpox?

Children who develop red, itchy lesions shouldn’t go to daycare, school and other activities. “They need to stay home,” Dr. Tan says. Call your child’s doctor to check in.

If you’re not vaccinated, you can protect yourself by getting a chickenpox vaccine within three to five days after virus exposure. If you’re pregnant, talk to your doctor.

What if my child can’t get the chickenpox vaccine?

The varicella vaccine contains live virus. Children who have a weakened immune system can’t receive it. Talk to their doctor if your child has been near someone who has chickenpox. They may need a dose of an antibody called varicella-zoster immune globulin to protect them.

Are there complications from chickenpox?

Chickenpox complications can occur in some children and adults with the illness. Complications are more likely to occur if you have a weakened immune system. These can include:

• Central nervous system issues (encephalitis, wobbly gait, stroke)
• Joint swelling (arthritis)
• Liver infection (hepatitis)
• Lung infections (pneumonia)
• Skin infections (such as group A strep)

Consult your child’s doctor if your child has a weakened immune system or long-term (chronic) health condition. Your child may need to see an infectious disease specialist if they’re at risk for chickenpox complications. These specialists monitor your child and manage any complications that may occur.

Learn more about infectious disease treatment

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