Chickenpox is a mild and common childhood illness that most children catch at some point.
It causes a rash of red, itchy spots that turn into fluid-filled blisters. They then crust over to form scabs, which eventually drop off.
Some children have only a few spots, but other children can have spots that cover their entire body. These are most likely to appear on the face, ears and scalp, under the arms, on the chest and belly, and on the arms and legs.
Read more about the symptoms of chickenpox and watch a slideshow of common childhood conditions to help you recognise if your child has it.
Chickenpox (known medically as varicella) is caused by a virus called the varicella-zoster virus. It’s spread quickly and easily from someone who is infected.
Read more about the causes of chickenpox.
Chickenpox is most common in children under the age of 10. In fact, chickenpox is so common in childhood that over 90% of adults are immune to the condition because they’ve had it before.
Children usually catch chickenpox in winter and spring, particularly between March and May.
What to do
To prevent spreading the infection, keep children off nursery or school until all their spots have crusted over.
Chickenpox is infectious from one to two days before the rash starts, until all the blisters have crusted over (usually five to six days after the start of the rash).
If your child has chickenpox, try to keep them away from public areas to avoid contact with people who may not have had it, especially people who are at risk of serious problems, such as newborn babies, pregnant women and anyone with a weakened immune system (for example, people having cancer treatment or taking steroid tablets).
Read more about what you need to do to stop chickenpox spreading.
Chickenpox in children is considered a mild illness, but your child will probably feel pretty miserable and irritable while they have it.
Your child may have a fever for the first few days of the illness. The spots can be incredibly itchy.
There is no specific treatment for chickenpox, but there are pharmacy remedies that can alleviate symptoms. These include paracetamol to relieve fever, and calamine lotion and cooling gels to ease itching.
In most children, the blisters crust up and fall off naturally within one to two weeks.
Read more about chickenpox treatments.
When to see a doctor
For most children, chickenpox is a mild illness that gets better on its own.
However, some children can become more seriously ill with chickenpox and need to see a doctor.
Contact your GP straight away if your child develops any abnormal symptoms, such as:
if the blisters on their skin become infected
if your child has a pain in their chest or has difficulty breathing
Chickenpox in adults
Chickenpox may be a childhood illness, but adults can get it too. Chickenpox tends to be more severe in adults than children, and adults have a higher risk of developing complications.
As with children, adults with chickenpox should stay off work until all the spots have crusted over. They should seek medical advice if they develop any abnormal symptoms, such as infected blisters.
Adults with chickenpox may benefit from taking antiviral medicine if treatment is started early in the course of the illness. Read more about antivirals in the treatment of chickenpox.
Who’s at special risk?
Some children and adults are at special risk of serious problems if they catch chickenpox. They include:
people with a weakened immune system
These people should seek medical advice as soon as they are exposed to the chickenpox virus or they develop chickenpox symptoms.
They may need a blood test to check if they are protected from (immune to) chickenpox.
Read more about immunity testing and the diagnosis of chickenpox in people at special risk.
Chickenpox in pregnancy
Chickenpox occurs in approximately 3 in every 1,000 pregnancies. It can cause serious complications for both the pregnant woman and her baby. See complications of chickenpox for further information on what to do if you are exposed to chickenpox during pregnancy.
Chickenpox and shingles
Once you have had chickenpox, you usually develop antibodies to the infection and become immune to catching it again. However, the virus that causes chickenpox, the varicella-zoster virus, remains inactive (dormant) in your body’s nerve tissues and can return later in life as an illness called shingles.
It’s possible to catch chickenpox from someone with shingles, but not the other way around.
Read more about shingles.
Is there a vaccine against chickenpox?
There is a chickenpox vaccine, but it is not part of the routine childhood vaccination schedule. The vaccine is only offered to children and adults who are particularly vulnerable to chickenpox complications.
The recommended two doses of the vaccine is estimated to offer 98% protection from chickenpox in children and 75% protection in adolescents and adults.
So it may be possible to develop the infection after vaccination. Similarly, there is a chance that someone who has received the vaccine could develop chickenpox after coming in close contact with a person who has shingles.