Chickenpox (varicella)
- Chickenpox is a highly contagious disease caused by the varicella zoster virus.
- It can cause serious health complications, especially in people with chronic diseases and weak immune systems.
- There is a vaccine to protect you against getting chickenpox.
Most children who get chickenpox have a mild illness, but some can become quite ill. Usually adults who get chickenpox have a more severe illness.
It is rare to have chickenpox more than once, as infection gives life-long immunity.
Once you have had chickenpox the virus lies dormant (inactive) in the nerves of the spinal cord and can reactivate later in life, this is known as shingles.
You cannot catch shingles from another person. People who are not immune to chicken pox and become exposed to someone with shingles will catch chickenpox.
How do you get chickenpox?
You usually get chickenpox by breathing in the varicella virus that has been coughed or sneezed into the air by an infectious person.
Although rare, you can also get chickenpox from direct contact with the shingles rash (touching the fluid in the blisters) of an infected person.
Chickenpox is highly contagious. If you have chickenpox you will be contagious (able to spread the virus) from up to 2 days before the red spots appear and until around 5 days after rash appears and until vesicles have formed crusts.
You will stop being contagious when there are no new blisters or moist crusts forming on your body.
If you have chickenpox, over 90 per cent of your close contacts (such as family and friends) will also get the virus if they have not previously been infected with chickenpox or have not been immunised against chickenpox.
If you suspect you or your child has chickenpox see your doctor for a diagnosis.
Caution: when making your doctor’s appointment, tell the staff that you may be infectious. You will need to wait in a separate area from others, especially young children.
Notifiable disease
Chickenpox and shingles are nationally notifiable diseases.
This means doctors, hospitals and laboratories must inform the Department of Health of your diagnosis. Notification is confidential.
Department of Health staff may talk to you or your doctor to find out how the infection occurred, to identify other people at risk of infection, to let you know about immunisation and to tell you if you need to stay away from work, school or other group gatherings.
Who is most at risk of chickenpox?
People with low immunity
Chickenpox can be a fatal illness for people who have immune problems, for example those with a chronic medical condition such as HIV/AIDS or those undergoing treatment for severe asthma or cancer.
All of these people need to be seen by a doctor urgently – within 3 days – if they come into contact with the virus. There is a vaccine and immunoglobulin which may be used to protect them from the severe effects of chickenpox. However the treatment must be given soon after coming in contact with an infected person.
Pregnant women and newborn babies
Ideally, women planning pregnancy should get their immunity checked to see if they have had the disease in the past and are now protected.
If you are pregnant and get chickenpox during the first half of your pregnancy, there is a risk of malformations in the baby.
If you develop chickenpox 5 days before you are due to deliver, or up until 2 days after the birth, there is 30 per cent risk that your baby could develop a severe, life-threatening infection.
If you are pregnant, it is important that you see their doctor if you have come into contact with the chickenpox virus and you are not sure whether you have previously had the infection.
If you have been exposed, and you have not already had chickenpox, you may be given an antiviral treatment or Zoster Immunoglobulin, if needed. This will give you temporary protection against the chickenpox.
This treatment may also be used for some other high risk people.
What are the signs and symptoms of chickenpox?
Symptoms of chickenpox usually take between 10 and 21 days (14 to 16 days on average) to show after exposure to an infected person.
Chickenpox usually starts with cold-like symptoms such as a runny nose and mild fever, which is followed by the appearance of a red spotty rash and generally feeling unwell.
The rash usually starts as red spots (vesicular) appearing over the body in small crops (including in your hair). Some children and adults will get spots all over their body including in the mouth and in the genital area. Spots do not appear on the palms of their hands or the soles of their feet.
The spots start as red, itchy raised lumps, and then dry up to form scabs, which can look like blisters. If the top comes off the scab, a watery fluid seeps out. This fluid is infectious to other people if touched.
The scabs can take 5 days or longer to fall off, depending on when they appear after infection.
The spots often come in waves for several days so there will be new spots, blisters and crusting sores on the skin at the same time.
The spots are very itchy, and if you scratch them you can cause a bacterial infection. An infected spot is more likely to leave a scar. However, expecting children not to scratch is usually too much to ask of them.
The virus usually lasts around 7 to 10 days.
Complications
- Adults usually have a more severe illness. A few adults get pneumonia and in some cases they may die from this complication. This is rare and only happens to about 3 in 100,000 healthy people.
- Chickenpox can be a fatal illness for people who have immune problems.
- Rarely, some people can become infected for a second time if they initially had a mild infection.
How are chickenpox treated?
- Drink plenty of fluids.
- Take paracetamol for fever and pain.
- Use soothing lotions, such as calamine lotion, or special oils that reduce the itching.
- Add sodium bicarbonate or oatmeal to a bath to soothe the itching.
- Take antihistamine medications to help with the itching.
- If you have blisters in your mouth, don’t eat foods with a lot of acid or salt. Soothing mouth washes are also available.
Antiviral medication
People who have severe health conditions that affect their immune system or pregnant women may be able to get some antiviral medications, such as acyclovir. Speak to your doctor if this applies to you.
Reye's syndrome
Never give aspirin to a child under 16 who has chickenpox – it increases the risk of a serious illness called Reye’s Syndrome.
Reye’s Syndrome can follow a viral infection such as chickenpox, flu or an upper respiratory infection. The syndrome causes brain damage and can be life threatening.
Where to get help
- See your doctor.
- See your local community child health nurse.
- Visit healthdirect (external site) or call 1800 022 222.
- Phone the Immunise Australia Hotline on 1800 671 811.
- Ngala Helpline
- Phone: 9368 9368
- Outside metro area – Free call 1800 111 546 (free from land line only).
- Chickenpox factsheet (PDF 267KB)
© Women’s and Children’s Health Network, reproduced with permission. The South Australian Government does not accept responsibility for the accuracy of this reproduction.
Last reviewed: 18-11-2024
Acknowledgements
Public Health
This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.