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Chickenpox

 

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 in others they can cover the entire body. The spots are most likely to appear on the face, ears and scalp, under the arms, on the chest and stomach and on the arms and legs.

Chickenpox (medically known as varicella) is caused by a virus called the varicella-zoster virus. It's spread quickly and easily through the coughs and sneezes of someone who is infected.

Chickenpox is most common in children under 10. In fact, chickenpox is so common in childhood that 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 the spots have crusted over.

Chickenpox is most 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 have not 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).

Chickenpox treatment

Chickenpox in children is considered a mild illness, but expect your child to feel pretty miserable and irritable while they have it.

Your child is likely to have a fever at least 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 which can alleviate symptoms, such as 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.

When to see a doctor

For most children, chickenpox is a mild illness that gets better on its own.

But some children can become more seriously ill with chickenpox. They need to see a doctor.

Contact your GP straight away if your child develops any abnormal symptoms, for example:

  • 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.

Who's at special risk?

Some children and adults are at special risk of serious problems if they catch chickenpox. They include:

  • pregnant women
  • newborn babies
  • 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 immune (protected from) chickenpox.

Chickenpox in pregnancy

Chickenpox occurs in approximately three in every 1,000 pregnancies. It can cause serious complications for both the pregnant woman and her baby.

Chickenpox and shingles

One 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 virus, remains dormant (inactive) in your body's nerve tissues and can return later in life as an illness called shingles.

It is 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.


 

Can I get chickenpox more than once?

Yes, you can!

In a study, up to 13% (around one in eight) of people diagnosed with chickenpox reported that they had had the condition before.

Usually, you develop antibodies to the infection first-time round, and become immune to catching it again.

It seems that some people simply don't develop the antibodies needed to protect them against re-infection.

But experts generally agree that if you've had chickenpox once before, you're unlikely to have it again. 

 

The most commonly recognised chickenpox symptom is a red rash that can cover the entire body.

However, even before the rash appears, you or your child may have some mild flu-like symptoms, including:

  • feeling sick
  • a high temperature (fever) of 38ºC (100.4ºF) or over
  • aching, painful muscles
  • headache
  • generally feeling unwell
  • loss of appetite

These flu-like symptoms, especially the fever, tend to be worse in adults than in children.

Chickenpox spots

Soon after the flu-like symptoms, an itchy rash appears. Some children and adults may only have a few spots, but others are covered from head to toe.

The spots normally appear in clusters and tend to be:

  • behind the ears
  • on the face
  • over the scalp
  • under the arms
  • on the chest and stomach
  • on the arms and legs

But the spots can be anywhere on the body, even inside the ears and mouth, on the palms of the hands, soles of the feet and inside the nappy area.

Although the rash starts as small, itchy red spots, after about 12-14 hours the spots develop a blister on top and become intensely itchy.

After a day or two, the fluid in the blisters gets cloudy and they begin to dry out and crust over.

After one to two weeks, the crusting skin will fall off naturally.

New spots can keep appearing in waves for three to five days after the rash begins. Therefore different clusters of spots may be at different stages of blistering or drying out. 

Unusual symptoms

Most healthy children (and adults) recover from chickenpox with no lasting ill-effects simply by resting, just as with a cold or flu.

But some children and adults are unlucky and have a more severe bout than usual.

Contact your GP straight away if you or your child develop any abnormal symptoms, for example:

  • if the skin surrounding the blisters becomes red and painful 
  • if you or your child start to get pain in the chest or have difficulty breathing
  • if your child is very unwell and you are concerned

In these cases, prescription medicine, and possibly hospital treatment, may be needed.


 

Chickenpox is caused by the varicella-zoster virus. You catch it by coming into contact with someone who is infected with the virus.

It's a very contagious infection. About 90% of people who have not previously had chickenpox will become infected when they come into contact with the virus.

How you catch the virus

The chickenpox virus is spread in the same ways as colds as flu. It's contained in the millions of tiny droplets that come out of the nose and mouth when an infected person sneezes or coughs. You can then become infected with the virus by breathing in these droplets from the air.

You can also become infected by handling a surface or object that these droplets have landed on, then transferring the virus to yourself by touching your face.

It takes 10-21 days for the symptoms of chickenpox to show after you have come into contact with the virus. This is called the 'incubation period'.

Someone with chickenpox is most infectious from one to two days before the rash appears until all the blisters have crusted over. This usually takes five to six days from the start of the rash.

Shingles

If you have not had chickenpox before, you can also catch chickenpox from someone with shingles (an infection caused by the same virus). However, it's not possible to catch shingles from someone who has chickenpox.

 

Contagious
Contagious is when a disease or infection can be easily passed from one person to another.

Have you been exposed to chickenpox?

As a rule of thumb, you have been exposed to chickenpox if you have:

  • been in the same room as an infected person for 15 minutes
  • had face-to-face contact with an infected person

You or your child should not usually need any medical tests to diagnose chickenpox. You can be pretty sure that it is chickenpox if there are the key symptoms of a mild fever followed by an itchy rash, blisters and scabs. 

Chickenpox spots are usually distinctive enough to distinguish from other rashes, although occasionally they can be easily confused with other conditions that affect the skin, such as insect bites or scabies (a contagious skin condition that causes intense itching).

If you're still uncertain about what is causing the symptoms, your GP can carry out a simple blood test to identify the virus.  

 

When to contact your GP

1. See your GP if you're not sure whether you or your child have chickenpox.

2. Contact your GP urgently if you have been in contact with someone who has chickenpox or you have chickenpox symptoms and:

  • you are pregnant
  • you have a weakened immune system (the body's defence system)
  • your baby is less than four weeks old

Chickenpox in these instances can cause serious complications if left untreated. It is essential to seek medical advice so that you can receive any necessary treatment.

3. Contact your GP if you have chickenpox and are breastfeeding. They can advise about whether you should continue breastfeeding your baby.

Having a blood test

Once you have contacted your GP, you may need a test to see if you're already immune from chickenpox.

If you have had chickenpox in the past, then it is extremely unlikely that you will develop chickenpox for a second time. If you've never had chickenpox, or you're unsure whether you've had it, then you may need an immunity test.

This is a blood test that checks whether you are producing the antibodies to the chickenpox virus.

If your blood test result shows that you have the antibodies, you'll be naturally protected from the virus. If you don't have the antibodies, then you'll need to be monitored closely to see if you develop chickenpox symptoms. If you do, you may require further treatment. 

Antibodies
Antibodies are your body's natural defence against any foreign antigens that enter your blood. An antibody is a protein that is produced by the body to neutralise or destroy disease-carrying organisms and toxins.
Contagious
Contagious is when a disease or infection can be easily passed from one person to another.
Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.

There is no cure for chickenpox, and the virus usually clears up by itself without any treatment.

However, there are ways of easing the itch and discomfort, and there are important steps you can take to stop chickenpox spreading.

Painkillers

If your child is in pain or has a fever (high temperature), you can give them a mild painkiller, such as paracetamol or ibuprofen. These are available over the counter in pharmacies. Always read the manufacturer's instructions.

Ibuprofen can cause problems for some children and adults, so avoid it if you or your child also have:

  • asthma
  • a history of stomach problems, such as stomach ulcers

If you're not sure whether ibuprofen is suitable, check with your GP or pharmacist. If your child is younger than three months old, always speak to your GP before you give your child any kind of pain relief.

If you're pregnant and need to take painkillers, then paracetamol is the first choice. You can use it at any stage of pregnancy. Only take ibuprofen during the second trimester (weeks 14-27 of the pregnancy).

Keeping hydrated

It is important for children (and adults) with chickenpox to drink plenty of water to avoid dehydration. Sugar-free ice-lollies are a good way of getting fluids into children. They also help to soothe a sore mouth that has chickenpox spots in it. 

Avoid any food that may make the mouth sore, such as salty foods. Soup is easy to swallow as long as it is not too hot.

Stop the scratching

Chickenpox can be incredibly itchy, but it's important for children (and adults) to not scratch the spots so as to avoid future scarring.

One way of stopping scratching is to keep fingernails clean and short. You can also put socks over your child's hands at night to stop them scratching the rash as they sleep.

If your child's skin is very itchy or sore, try using calamine lotion or cooling gels. These are available in pharmacies and are very safe to use. They have a soothing, cooling effect.

A stronger medicine called chlorphenamine can be prescribed by your GP to relieve itching. It's taken by mouth and is suitable for children over one year old.

Cool clothing

If your child has a fever, or if their skin is sore and aggravated, dress them appropriately so that they don't get too hot or too cold. Loose-fitting, smooth, cotton fabrics are best and will help stop the skin from becoming sore and irritated.

If your child has chickenpox, avoid sponging them down with cool water. This can make your child too cold, and it may make them shiver.

Stronger treatments

Antiviral medicine

Aciclovir is an antiviral medicine that is sometimes given to people with chickenpox.

Aciclovir may be prescribed to:

  • pregnant women
  • adults, if they visit their GP within 24 hours of the rash appearing
  • newborn babies
  • people with a weakened immune system (the body's defence system)

Ideally, aciclovir needs to be started within 24 hours of the rash appearing. It does not cure chickenpox, but it makes the symptoms less severe. You normally need to take the medicine as tablets five times a day for seven days.

If you are taking aciclovir, make sure you drink plenty of fluids. Side effects are rare but can include nausea and diarrhoea.

Immunoglobulin treatment

Immunoglobulin is a solution of antibodies that is taken from healthy donors. Varicella-zoster immunoglobulin (VZIG) contains antibodies to the chickenpox virus.

Immunoglobulin treatment is given by drip. It is not used to treat chickenpox but to protect people who are at high risk of developing a severe chickenpox infection. This includes:

  • pregnant women
  • newborn babies
  • people with weakened immune systems

In the case of pregnant women, immunoglobulin treatment also reduces the risk of the unborn baby becoming infected.

As the supply of VZIG is limited, it will only be considered if a high-risk person has:

  • been significantly exposed to the virus - significant exposure could be face-to-face contact with someone who has chickenpox
  • been in the same room for 15 minutes with someone who has chickenpox
  • had a blood test to confirm that they've not had chickenpox before

In some cases, newborn babies may be given immunoglobulin treatment without having a blood test first.

Antibodies
Antibodies are your body's natural defence against any foreign antigens that enter your blood. An antibody is a protein that is produced by the body to neutralise or destroy disease-carrying organisms and toxins.
Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.

Aspirin alert

Never give your child aspirin if you suspect or know that they have chickenpox.

Children with chickenpox who take aspirin can develop a potentially fatal condition called Reye's syndrome, which causes severe brain and liver damage.

Speak to your GP or pharmacist if you are not sure which medicines to give your child. 

Complications of chickenpox are rare in healthy children. The most common one is when the rash of blisters becomes infected with bacteria.

A sign that the blisters have become infected is when the surrounding skin becomes red and sore.

If you think that your child's blisters have become infected, contact your GP as the child may need a course of antibiotics.

The people who are most at risk of developing chickenpox complications are:

  • adults
  • pregnant women
  • babies under four weeks old
  • people with a weakened immune system 

Adults

Chickenpox can be more serious in adults than in children. Adults with the virus are more likely to be admitted into hospital. Approximately 5-14% of adults with chickenpox develop lung problems, such as pneumonia. If you smoke, your risk of developing lung problems is much greater.

Although it is more serious in adults, most people will still make a full recovery from the chickenpox virus.

Pregnant women

If you're pregnant, chickenpox can occasionally cause complications.

For example, your risk of developing pneumonia is slightly higher if you're pregnant, especially if you smoke. The further you are into your pregnancy, the more serious the risk of pneumonia tends to be.

If you get chickenpox while you're pregnant, there is also a small but significant risk to your unborn baby.  

If you are infected with chickenpox during the first 20 weeks of your pregnancy, there is a risk that your unborn baby could develop a condition known as foetal varicella syndrome.

This syndrome is rare. The risk of it occurring in the first 12 weeks of pregnancy is less than 1%. Between 13 and 20 weeks, the risk is 2%.

Foetal varicella syndrome can cause serious complications, including:

  • scarring 
  • eye defects, such as cataracts
  • shortened limbs
  • brain damage

There have been reports of damage to the unborn baby from foetal varicella syndrome when a pregnant woman catches chickenpox after week 20. But the risk at this late stage in pregnancy is thought to be much less than 1%. 

However, there are other risks from catching chickenpox after week 20 of pregnancy.

It is possible that your baby may be born prematurely (before week 37 of the pregnancy).

And if you are infected with chickenpox seven days before or seven days after giving birth, your newborn baby may develop a more serious type of chickenpox. In a few severe cases, this type of chickenpox can be fatal.

See your GP urgently if you're pregnant or have given birth in the last seven days and you think you may have chickenpox, or if you've been exposed to someone who has chickenpox.

 

People with a weakened immune system

Your immune system is your body's way of defending itself against disease, bacteria and viruses.

If your immune system is weak or does not work properly, you are more susceptible to developing infections such as chickenpox. This is because your body produces fewer antibodies to fight off the infection.

You may have a weakened immune system if you take immunosuppressive medication. This is medicine that works by damping down your immune system.

Immunosuppressive medication such as steroid tablets may be used if, for example, you have an inflammatory condition such as rheumatoid arthritis, lupus or certain blood conditions.

If you have a weakened immune system, you're also more at risk of developing complications from chickenpox. These complications include:

  • pneumonia
  • septicaemia (blood poisoning)
  • meningitis

See your GP urgently if you have a weakened immune system and you've been exposed to the chickenpox virus.

Antibiotics
Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi.
Antibodies
Antibodies are your body's natural defence against any foreign antigens that enter your blood. An antibody is a protein that is produced by the body to neutralise or destroy disease-carrying organisms and toxins.
Chemotherapy
Chemotherapy is a treatment of an illness or disease with a chemical substance, e.g. in the treatment of cancer.
Foetus
A foetus is an unborn baby, from the eighth week of pregnancy until birth.
Hormones
Hormones are groups of powerful chemicals that are produced by the body and have a wide range of effects.
Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.
Inflammation
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

If your child has chickenpox, inform their school or nursery and keep them at home while they are infectious, which is until the last blister has burst and crusted over. This usually takes five or six days after the rash begins.

If you have chickenpox, stay off work and at home until you're no longer infectious.

If either you or your child has chickenpox, it is also a good idea for you, or them, to avoid contact with:

  • pregnant women
  • newborn babies
  • anyone who has a weak immune system, such as people who are having chemotherapy (a treatment for cancer) or taking steroid tablets

If you or your child have recently been exposed to the chickenpox virus, you may not be able to visit friends or relatives in hospital. Telephone the ward to check first.

Travelling on a plane 

If you or your child have chickenpox, you may not be allowed to fly until six days after the last spot has appeared.

You and your child should be safe to fly once you're past the infectious stage and all of the blisters have crusted over. But it's best to check the policy of your airline first. Inform the airline as soon as chickenpox is diagnosed.

It is also important to let your travel insurer know if you or your child have chickenpox. You need to make sure that you'll be covered if you have to delay or cancel your holiday, or if you need to extend your stay until your child is well enough to fly home.

Stop the virus spreading

Chickenpox can sometimes be spread through contact with objects that have been infected with the virus, such as children's toys, bedding or clothing.

If someone in your household has chickenpox, you can help stop the virus spreading by wiping any objects or surfaces with a sterilising solution and making sure that any infected clothing or bedding is washed regularly.

Vaccination

There is a chickenpox vaccine that is used to protect people who are most at risk of a serious chickenpox infection or of passing the infection on to someone who is at risk.

People who may be considered for chickenpox vaccination include:

  • healthcare workers who are not already immune - for example, a nurse who has never had chickenpox and who may pass it to someone they are treating if they become infected
  • people living with someone who has a weakened immune system - for example, the child of a parent receiving chemotherapy

The vaccine is not suitable for pregnant women. Avoid getting pregnant for three months after having the vaccine. The vaccine is also not suitable for people with weakened immune systems.

Chemotherapy
Chemotherapy is a treatment of an illness or disease with a chemical substance, e.g. in the treatment of cancer.
Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.