Chickenpox (Varicella) is a common viral illness caused by the varicella-zoster virus.


The illness begins with fever and/or general unwellness (headache, cough, runny nose, tiredness) for a day or two followed by a rash:

  • Usually starts with one spot - more spots quickly appear starting on the chest and back, then spreading to the face, scalp, arms and legs. (Can also spread inside the ears, on the eyelids, inside the nose and within the vagina.)
  • Within a few hours after each spot appears, a blister forms.  The blisters are easily broken and form a scab.
  • Rash continues to spread for three or four days and is usually very itchy.
  • The blisters heal at different stages, some faster than others, so your child may have the rash in several different stages at once.

How is it spread?

The virus is easily spread when an infected person sneezes or coughs and also by direct contact with weeping blisters.

People with chickenpox are infectious from two days before the rash appears and remain infectious until all the blisters form scabs. Generally, this takes up to seven days.

If one person has chickenpox, about 85% of their close contacts will get it too, unless they have already had the disease (or the varicella vaccine).  It usually takes about ten to 21 days for the illness to show up after your child has come into contact with an infectious person.

Children must stay away from school while they are infectious.   

Once all the spots have formed scabs, the person is no longer infectious.

Your child may go back to school seven days after the first spots appear, as long as the spots are all scabbed over.

Is it serious? 

Chickenpox is usually, but not always, a mild, self-limited disease in otherwise healthy children. However the severity of disease and risk of complications can be greater in adults. Complications can include severe tissue infection, low platelet count, pneumonia and inflammation of the joints, kidneys and liver.  The risk of serious complications is higher in people with immune-suppression (eg leukaemia) and in pregnant women.

Shingles is a long-term complication that is not immediately apparent but can appear decades after the disease.

Key points to remember:

  • Most cases of chickenpox are mild and children get better completely
  • Scarring can happen if your child scratches the spots and they get infected
  • Your child needs to see a doctor if they have a very high fever or are very ill, such as being very drowsy, breathing fast or vomiting a lot
  • Never give your child aspirin as this may increase the risk of Reye syndrome, which is a rare and serious illness
  • Chickenpox can be prevented by immunisation, but vaccination is not currently funded in New Zealand.  Talk to your Doctor or Practice Nurse if you are interested in your child having this vaccine.

Contact your GP or Heathline (0800 611 116) for further advice.