Chickenpox

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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
  • if your child is miserable, you can give paracetamol (not aspirin) to make them more comfortable. You must follow the dosage instructions on the bottle. It is dangerous to give more than the recommended dose (see What is the treatment?)
  • your child needs to see a doctor if they have a very high fever or are very ill, particularly if they become very drowsy, or are breathing fast or vomiting a lot

What is it?

Chickenpox is a viral illness. The chickenpox virus is also called varicella virus or varicella zoster virus. It is the same virus that can cause shingles. 

Chickenpox usually starts with one spot, but more spots quickly appear, with:

  • fever
  • headache
  • runny nose
  • a cough, and
  • feeling very tired

The rash starts on the chest and back, and spreads to the face, scalp, arms and legs. The rash can develop all over the body, inside the ears, on the eyelids, inside the nose and within the vagina, everywhere. The rash continues to spread for three or four days. It is usually very itchy.

Within a few hours after each spot appears, a blister forms. It may appear full of yellow fluid. After a day or so, the fluid turns cloudy. These spots are easily broken and form a scab. The spots heal at different stages, some faster than others, so your child may have the rash in several different stages at once.

Some kids breeze through chickenpox with just a few spots. Others have a terrible time with hundreds of itchy spots. In families with several children, the illness can last for several weeks within the family if subsequent family members become infected because of the relatively long incubation period.

What is the incubation period?

The incubation period is the time between the initial exposure to infection and appearance of the first symptoms.

A parent doesn't always know when their child has been exposed to chickenpox.

Some susceptible children can come into contact with chickenpox and yet not show signs of having caught it. But the general rule is that chickenpox will show up about ten to 21 days after your child has come into contact with an infectious person, if your child is susceptible to infection with the chicken pox virus. A child is susceptible to chicken pox either because they have never been vaccinated or they have never had chicken pox.

How long will my child be infectious?

Chickenpox is a highly catching (contagious), common childhood disease.

A child is infectious from two days before the rash appears and stays infectious until all the blisters form scabs and are dry. Generally, this takes seven days.

Children must stay away from daycare or school while they are infectious. The virus is easily spread when an infected person sneezes or coughs. You can catch chickenpox from clothing that has fresh discharge from the rash of an infected person.

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 and dry.

Chickenpox is most common in children between the ages of two and ten years. If one child in your household gets it, it is almost certain that any others who have never had chickenpox will get it next. Some children catch chickenpox but do not develop a rash.

What is the treatment?

  • most children do not need any treatment for chickenpox – a soothing lotion such as calamine lotion can be put on the spots to help relieve the itching
  • for fever or pain, you can give your child paracetamol. You must follow the dosage instructions on the bottle. It is dangerous to give more than the recommended dose. 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 (see Where to go for more information)

How to prevent scarring

Secondary bacterial infection of the spots can be caused by your child scratching, which can lead to scars.

To help prevent scarring from the spots:

  • dress your child in lightweight pyjamas or clothing
  • clip your child's fingernails as closely as you can
  • try putting mittens on the hands of very young children
  • try 20-minute baths, three times a day, with baking soda or an oatmeal type bath product in lukewarm water
  • change your child's clothes and bed sheets daily
  • apply a soothing lotion such as calamine lotion
  • if your child is fidgety and wants to scratch the spots, your doctor may suggest an anti-itch medicine

Acknowledgements

Starship Foundation and the Paediatric Society of New Zealand acknowledge the co-operation of The Children's Hospital at Westmead, Sydney Children's Hospital at Randwick, and Kaleidoscope - Hunter Children's Health Network in making this fact sheet available to patients and families.

This page last reviewed 15 June 2012
© Paediatric Society of New Zealand and Starship Foundation 2005 – 2014
Printed on 29 July 2014. Content is regularly updated so please refer to www.kidshealth.org.nz for the most up-to-date version
Content endorsed by the Paediatric Society of New Zealand