Expert reviewer, Dr Adrian Raby, General Practitioner and Clinical Lecturer
Next review due February 2019

Chickenpox is a highly contagious infection, which means it spreads easily from person to person. If you’ve not had chickenpox before and someone in your household gets it, it’s very likely you’ll catch it too.

Chickenpox is a common infection caused by the varicella zoster virus. It causes an itchy, spotty rash. The spots start flat then become raised and blistered, before crusting over. For most people, chickenpox isn’t serious. You’ll probably feel better after a week or so.

You can catch chickenpox at any time of year, but it’s most likely in spring. It’s most common in children under 10, but you can catch it at any age. Once you have had chickenpox, you’re very unlikely to catch it again. About nine out of 10 adults are immune as a result of catching chickenpox when they were a child.

If you’ve had chickenpox, the varicella zoster virus will stay dormant in your body for the rest of your life. At any time later in life, the virus could be reactivated, causing shingles.

Three young girls sat on a sofa

Symptoms of chickenpox

If you catch the chickenpox virus, you’ll begin to get symptoms 10 to 21 days later. The first symptoms can include:

  • mild headache
  • fever
  • loss of appetite
  • nausea
  • a general feeling of being unwell

The infection can be milder in children than in adults – some children may not get these initial symptoms. A day or two after your first symptoms, you’ll get a rash with flat or slightly raised red spots. You’ll probably get them on your face and chest first, and they may spread to your arms and legs in patches. You may also get spots in your mouth, nose and genitals.

Image showing boy with chickenpox

Your spots might become filled with fluid, forming small blisters. These can be extremely itchy and will usually crust over within a few days, forming scabs. Your spots will probably take around two weeks to heal completely. They don’t usually leave a scar, unless they get infected. This may be more likely if you scratch them.

Image showing chickenpox blisters
Chickenpox blisters

The severity of chickenpox varies – it’s possible for children to be infected but show no symptoms. Some children may have only a few blistered spots, while others will have extensive spots. You may have a fever for longer, or you may become more unwell and develop complications.

If you have a young child, keep an eye out for signs of high fever and dehydration (eg urinating less, tiredness, cold fingers and toes, and reduced skin elasticity). If your child shows these signs, seek immediate medical advice.

These symptoms aren’t always caused by chickenpox. They could also be caused by another viral or bacterial infection or skin condition.

Diagnosis of chickenpox

You’ll probably be able to tell that you have chickenpox because it comes with a particular rash. If you’ve recently been in contact with anyone who has chickenpox, this can help to confirm your diagnosis.

If you’re not sure that your symptoms are caused by chickenpox, you feel particularly unwell, or if you're pregnant or have a weakened immune system, contact your GP.

Because chickenpox is highly contagious, it’s best to let your GP (or whoever you speak to on the phone at your surgery) know that you think it may be chickenpox. If you need to be seen, they may want to keep you away from other patients by asking you to wait in a different room to the waiting room. This is to make sure you don’t pass the infection on to people who are at risk of complications from it, such as women who are pregnant.

Treatment of chickenpox

Most people with chickenpox don’t need any specific treatment and get better without any medicine.


The following tips may help.

  • Drink enough fluids.
  • Make sure you’re not too hot or cold.
  • Wear smooth, cotton fabrics to reduce any irritation to your rash.
  • Keep your nails short to reduce any skin damage caused by scratching.

Chickenpox spots are usually very itchy, but try not to scratch them as it can make them infected.


Calamine lotion may help soothe and reduce the itchiness of your rash. You can buy this at a pharmacy. You can use paracetamol if you have fever or pain – children can have paracetamol (eg Calpol) too. Always read the patient information leaflet that comes with your medicine. If you have any questions, ask your pharmacist for advice.

You can also take an antihistamine, such as chlorphenamine, which might help with your itching. These can be bought over the counter from a pharmacy. Antihistamines are taken by mouth and are suitable for children over the age of one.

If you’re over 14 years old and at risk of complications, you may be offered an antiviral drug called acyclovir (Zovirax) or valaciclovir. This can help to reduce your symptoms and recover faster if taken within 24 hours of the rash appearing. If you smoke or take steroids, you may be more likely to get complications. As with all medicines, acyclovir can cause some side-effects, such as diarrhoea and vomiting.

If you have a weakened immune system, have a very young baby, or are pregnant and come into contact with someone who has chickenpox and you or your infant haven’t had it before, speak to your GP straightaway. You might be offered an injection that contains antibodies. Antibodies are proteins that help your immune system to fight bacteria and viruses. You’ll need to have the injection of varicella zoster immune globulin within 10 days of coming into contact with someone who has chickenpox for it to work. This antibody treatment is known as passive immunisation, and is different to having a vaccination.The antibodies are unlikely to stop you developing chickenpox, but they may make your symptoms milder. You may also be given an antiviral medicine to take.

Causes of chickenpox

Chickenpox is highly contagious, meaning it spreads from person to person very easily. If you come into contact with someone who has chickenpox and you haven’t previously had it, you’re very likely to catch it.

Chickenpox is usually transferred through the air when you cough or sneeze, or by touch.

The incubation period (the time from when you get infected to when you get symptoms) is between 10 and 21 days. The most infectious period is one to two days before the rash appears. You can catch it from that time up until the spots crust over (about five to six days after the rash appears).

Complications of chickenpox

Although rare, complications are more likely in adults than children. But if you're generally healthy, chickenpox is usually a mild infection and it’s unlikely you’ll have serious problems.

Chickenpox can be more serious for pregnant women, newborn babies or people with a weakened immune system. For example, if you have HIV/AIDS, have had an organ transplant or are taking certain medicines your immune system may be weaker. Older people, those taking steroids or those with cancer are also at greater risk of complications.

Your rash or spots could get infected with bacteria. This is more common in children under five and can leave scars.

Chickenpox can cause inflammation of your lungs (pneumonitis) or brain (encephalitis). It can also cause a lung infection (pneumonia), which is more likely if you smoke. If you get any of these complications, you may need to stay in hospital to receive treatment.

At any time later in life, the varicella zoster virus can be reactivated. If this happens, you’ll develop shingles. Shingles causes a blistering rash that appears in patches, and it can be very painful.

Prevention of chickenpox

If you have chickenpox, it’s best to avoid contact with anyone else unless they have been warned about your chickenpox. It’s particularly important to stay away from pregnant women, newborn babies and those with a weakened immune system. Therefore, stay away from busy public places and your GP surgery.

Keep your child off school or nursery for five days from the onset of the rash. Airlines have a right to refuse you if you’re unwell and you shouldn’t travel if you have chickenpox until all your spots have crusted over. This is because they have a duty to protect other passengers.

There’s a vaccine that can help prevent chickenpox, but it’s only recommended for certain people. For example, healthcare workers and those in contact with others with a weakened immune system might be offered it. See our FAQ for more information.

Chickenpox and pregnancy

If you’re pregnant and come into contact with someone who has chickenpox, there’s no problem if you’ve had chickenpox before or have been vaccinated. If you’ve never had chickenpox or aren’t sure, see your midwife or GP as soon as possible. You can have a blood test to find out whether you’re immune (this checks whether you already have antibodies to chickenpox).

If you’re not immune, you may be advised to have antibody treatment (varicella zoster immune globulin) to help protect you. This can work up to 10 days after you come into contact with someone with the virus, so see your midwife or GP as soon as possible if you think you’re at risk.

If you develop any rash during pregnancy, it’s a good idea to contact your midwife or GP.

Women who are pregnant are more likely to get complications from chickenpox, such as pneumonia. So, if you have chickenpox and develop symptoms of a chest infection (eg shortness of breath, chest pains or coughing), see your GP.

Chickenpox in the first half of pregnancy

If you aren’t immune to chickenpox and catch it during the first six months of pregnancy, there’s a small risk it could affect your baby. Getting chickenpox in the first trimester (12 weeks) doesn’t seem to increase the chance of having a miscarriage.

You may be given an injection of antibodies, called varicella zoster immune globulin, to help fight the virus. This doesn’t always prevent you developing chickenpox, but it can make symptoms milder and not last as long. You can have the injection up to 10 days after you come into contact with chickenpox and before any symptoms appear. It doesn’t work if you’ve already developed blisters.

Chickenpox in the second half of pregnancy

If you get chickenpox late in your pregnancy, especially around the time you give birth, your baby could get chickenpox too. You may be offered an antiviral medicine called acyclovir. Also, contact your GP or seek urgent medical advice from your midwife or health visitor if you get chickenpox within a week of giving birth. Your baby can be treated with injections of antibodies to help protect him or her.

If you have chickenpox and want to breastfeed, ask your GP for advice. If you have a chickenpox spot near a nipple, don’t breastfeed from that side (express and discard the milk).

Frequently asked questions

  • You’re most infectious from one to two days before your rash appears. You can pass on chickenpox to others until all your spots have crusted over. This is usually about five to six days after the onset of the rash.

  • Airlines have a right to refuse you if you’re unwell. It’s their duty to protect other passengers. You shouldn’t travel by plane until all your spots have crusted over, which is usually five days after your rash appeared. This is because you could pass on the infection to other passengers.

  • If you have chickenpox, try to stay away from people who haven’t had it before, particularly pregnant women, newborn babies and those with a weakened immune system.

    More information

    You’re most infectious from one to two days before the rash appears until all your spots have crusted over. Pregnant women, young babies and people with a weakened immune system are more likely to develop complications from chickenpox. To reduce the chance you’ll pass on the infection to these people, stay away from hospitals, GP surgeries and public places until your spots have crusted over, unless otherwise instructed by your doctor.

  • Yes, there is a vaccine that can help prevent chickenpox. But in the UK, it’s only recommended for certain people. Healthcare workers and those in regular close contact with someone who has a weakened immune system may be offered the vaccine, if they’re not immune already.

    More information

    Vaccines work by stimulating your immune system to produce antibodies (proteins that fight bacteria and viruses).

    The chickenpox vaccine (called Varilrix or Varivax) contains a small amount of a weakened form of the varicella zoster virus that causes chickenpox. If you have the vaccine, your body will ‘learn’ how to fight the virus, meaning you’re very unlikely to get chickenpox in the future.

    There are no plans for the vaccine to be given routinely to all children in the UK. But your child may be offered the vaccine as a precaution if they could pass on an infection to someone at higher risk of getting complications. So, for example, if you’re receiving chemotherapy, your children may be given the vaccine if they haven’t had chickenpox. This is so there is less chance of them catching chickenpox at school, nursery or a playgroup, and then passing it on to you.

    The vaccine is not suitable for people who have a weak immune system.

    The vaccination is given as two injections one to two months apart. If you’re due to have the vaccine but you’re ill, wait until you feel better before getting it.

  • No, once you’ve had chickenpox, it’s likely you’ll stay immune for life. This means you’re unlikely to catch it again and so won’t spread it to others. If your children have chickenpox, try to keep them away from public places until their chickenpox spots have crusted over. 

    More information

    The chance of catching chickenpox more than once is very small, although it can happen. Once you have recovered from chickenpox, the virus stays in your body, lying dormant or hidden. At any time later in life, the virus can be reactivated, causing shingles. If you have shingles, you can pass on the virus to others, causing them to develop chickenpox. But you cannot catch shingles from someone with chickenpox.

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Related information

    • Chickenpox. NICE Clinical Knowledge Summaries., published June 2015
    • Varicella. Green Book, Chapter 24. Department of Health., published August 2015
    • Chickenpox (varicella). MSD Manuals., published April 2013
    • Chickenpox. PatientPlus., published June 2013
    • Chickenpox. Medscape., published February 2015
    • Map of Medicine. Chickenpox. International View. London: Map of Medicine; 2015 (Issue 2)
    • Aciclovir. Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press., accessed October 2015
    • Shingles. NICE Clinical Knowledge Summaries., published May 2013
    • travel – health issues. Fit to Travel., accessed November 2015
    • Chickenpox and pregnancy. Royal College of Obstetricians and Gynaecologists., published June 2015
    • Vaccines and immunological products. PatientPlus., published January 2013
  • Reviewed by Alice Rossiter, Specialist Health Editor, Bupa Health Content Team, February 2016
    Expert reviewer, Dr Adrian Raby, General Practitioner and Clinical Lecturer
    Next review due February 2019

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