Chickenpox (Varicella)

Chickenpox (varicella) is caused by varicella zoster virus (VZV). It is an acute viral illness, but may be severe in infants, pregnant women, adults, and persons with weakened immune systems. A vaccine is available to prevent the disease. However, some people who have had the vaccine may still get the chickenpox (breakthrough disease), but it is usually very mild.

Signs and Symptoms

  • An itchy rash starts on the trunk and face with pink spots and tiny fluid-filled blisters ("pox") that then dry and become scabs in 4 to 5 days. 
  • Fever 
  • Fatigue

The rash may be mild with a few pox or severe with hundreds of pox lesions. Chickenpox can sometimes have severe complications such as bacterial skin infections and pneumonia. Some children who have been vaccinated against chickenpox can get a mild case of chickenpox with a small number of spots that may not blister or crust. 


  • Chickenpox virus is highly contagious and is spread by direct contact with saliva or the rash from an infected individual or by respiratory secretions released into the air from sneezing or coughing. 
  • The illness starts 10 to 21 days after contact with an infected person. 
  • Chickenpox is most contagious during the first 2 to 5 days that someone is sick. That period usually begins about 1 to 2 days before the rash appears. The contagious period is not over until all of the blisters have scabbed over.
  • If you suspect your child has chickenpox, please keep him/her at home.

People with immune systems weakened by illness or medications may have severe and prolonged illness. A person who has never had chickenpox or chickenpox vaccine has a 90% chance of becoming infected if exposed to a family member with chickenpox. 


  • Calamine lotion and colloidal oatmeal baths may help relieve some of the itching
  • Keep fingernails trimmed short to prevent skin infections from scratching
  • Give a non-aspirin medication, such as Tylenol to reduce fever.
  • Do not use aspirin based medication to treat chickenpox as it can cause a serious illness (Reyes disease) which can lead to liver and brain damage.


  • Vaccination is the best way to prevent chickenpox. Varicella vaccine is highly effective at preventing chickenpox, especially severe cases of the disease and its complications. 
  • Two doses of varicella vaccine are required for school attendance or a certificate of exemption signed by a physician.
  • If your child has not been vaccinated or have proof of previous disease they may be excluded from school.
  • If you are not sure whether you have had chickenpox, talk to your healthcare provider about getting a blood test. 

If exposed to chickenpox

  • If you are already immune to chickenpox, you most likely won't become sick. 
  • If you're not already immune to chickenpox, varicella vaccine given within 3 days of exposure can help prevent chickenpox. Vaccination 3 to 5 days after exposure probably won't prevent chickenpox but may make it milder. 
  • Persons at high risk for complications from chickenpox, such as persons with weakened immune systems, pregnant women, and premature infants, should contact their healthcare provider immediately.

Contact school nurse Lea Hysom at or 425-898-1720 ext. 399 to report a case of chickenpox.

More information about chickenpox is available on the CDC website.