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What is chickenpox?

Chickenpox is usually a mild illness in children. Infection in teenagers, newborn babies, adults and people with weakened immune systems can be more serious or even life-threatening. 

Children with chickenpox can get pneumonia or other serious complications like bacterial skin infections and encephalitis (brain inflammation), though they are uncommon. 

About 1 in every 3,000 adults with chickenpox will die from the infection.

Is chickenpox dangerous?

Children with chickenpox can get pneumonia or other serious complications. Necrotizing fasciitis (flesh-eating disease) is an uncommon but serious complication of chickenpox in young children.

Chickenpox can be very serious or even life-threatening to newborn babies, adults and anyone with immune system problems. Be sure to tell the family of a child with immune system problems immediately if there is a case of chickenpox at the school or child care centre.


  • Chickenpox begins with a fever, runny nose, cough and muscle aches. 
  • A day or two later, a rash appears on the body. The rash starts with itchy, red spots that soon become blisters filled with fluid. 
  • After a few days, a hard cover or crust forms over each blister. Blisters that get infected will scar.
  • Chickenpox usually lasts about ten days.


Chickenpox is caused by the varicella-zoster virus (VZV).

How chickenpox spreads

The virus spreads quickly through the air when an infected person breathes, coughs or sneezes. People can also catch chickenpox if they touch the fluid of a chickenpox blister, then touch their eyes or nose. It is difficult to stop the spread, because it is most contagious a day or two before the rash appears. The only way to stop the spread of the virus is to stay away from an infected person.


In most cases, chickenpox is a mild illness. If you have chickenpox, you should rest, but you do not need to stay in bed.

Anyone infected with chickenpox should not go to work or school for five days after the beginning of a rash or until blisters have crusted over. 

  • Drink lots of liquids such as water, juice and soup, especially if there is a fever. If your baby is breastfeeding, feed your baby more often.
  • Keep fingernails short and clean, and for kids, cover hands with gloves or socks at night to prevent scratching.
  • Keep the skin cool to relieve itching. Dress lightly and avoid hot baths and showers. Ask your pharmacist or health care provider about lotions that can reduce itching.
  • Prevent the spread of infection by using a household cleaner to wash any clothing or other items soiled with fluid from chickenpox blisters. Keep the infected person away from other family members who have not had chickenpox.

What to do at home 

  • your child is exposed to chickenpox, watch for signs of it for 2 to 3 weeks. Even if your child has had the vaccine, there is a small chance that your child could still catch chickenpox. During this time, stay away from people with immune system problems and from hospitals (except in an emergency).
  • your child gets chickenpox, tell the child care centre or school.
  • Children with chickenpox should be kept comfortable:
    • give cool baths
    • keep fingernails short and clean to prevent scratching
    • keep hands clean
    • put socks on child’s hands at night to prevent scratching
    • give the child plenty to drink
  • Talk to your doctor immediately if anyone in the home has an immune system problem.
  • Other household members should check their immunity to chickenpox. Anyone 12 months or older who has not had the chickenpox disease should get the chickenpox vaccine.

For pregnant or immunocompromised people

Pregnant women

Chickenpox can be severe and preventable. All adult women who have never had chickenpox should ask their doctor about the chickenpox vaccine.

There are risks of complications for the mother and baby before, during and after pregnancy.  If chickenpox happens early in pregnancy, there is a slight chance the baby will develop serious birth defects. 

A pregnant woman who is not immune to chickenpox should call her doctor right away if she thinks she has been exposed to the virus, as Varicella zoster immune globulin (VZIG) may be offered to prevent or reduce complications of chickenpox. This shot must be offered to prevent or reduce complications of chickenpox. This shot must be received no later than 96 hours (4 days) after exposure.

People with high-risk complications

There is a medication for people with a high risk of complications if they get chickenpox. It is for people over 13 years of age, children over one year of age with chronic skin or lung disorders and children on chronic aspirin treatment. It may also be used with pregnant women and those with immune system problems. This medication must be prescribed by a doctor and given within 24 hours after the rash develops. It is not recommended for healthy children who get chickenpox.