Chickenpox

Chickenpox is a common illness, and it's usually mild. Most cases are in children, but you can catch it at any age.

Chickenpox, known medically as varicella, is caused by the varicella-zoster virus. It spreads quickly and easily from a person who is infected.

Chickenpox is most common in children under the age of 10. Children usually catch it in winter and spring, particularly between March and May.

Chickenpox causes a rash of red, itchy spots that turn into fluid-filled blisters. These then crust over to form scabs, which eventually drop off.

The spots normally appear in clusters and tend to be:

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

But the spots can be anywhere on the body, including:

• inside the ears and mouth
• on the palms of the hands
• soles of the feet
• inside the nappy area.

The rash starts as small, itchy red spots. A blister develops on top of each one, and after about 12 to 14 hours the spots become very itchy.

A day or two later, the fluid in the blisters gets cloudy and they begin to dry out and crust over. Within 1 to 2 weeks, the crusted skin will fall off naturally.

New spots can keep appearing in waves for 3 to 5 days after the rash begins. So you may see different groups of spots at different stages of blistering or drying out.

Before the chickenpox rash appears, you or your child may have some mild flu-like symptoms, including:

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

These symptoms, especially the fever, tend to be more common and worse in adults than in children.

For most children, chickenpox is a mild illness that clears up on its own. In adults it tends to be more severe, and adults are more likely to develop complications.

Talk to a doctor if you or your child develop any abnormal symptoms, such as:

• the skin around the blisters becomes hot, red and painful (redness may be harder to see on brown or black skin)
• pain in the chest or difficulty breathing
• signs of dehydration, such as fewer wet nappies, drowsiness and cold hands and feet
• blisters on the skin become infected
• any of your or your child's symptoms suddenly get worse

You should also talk to a doctor if you have been in contact with someone who has chickenpox, or you have chickenpox symptoms, and:

• you are pregnant or have given birth in the last 7 days
• you have a weakened immune system (the body's defence system)
• your baby is less than 4 weeks old
• you are breastfeeding

If you can't reach a doctor, call the 16263 health line.

You can prevent chickenpox by having the MMRV vaccine.

There is no treatment that cures chickenpox. But you can get remedies from a pharmacy that help with the symptoms. These include:

• paracetamol to help bring down a fever
• calamine lotion and cooling gels to ease itching.

In most children, the blisters crust over and fall off on their own within 1 to 2 weeks.

Adults with chickenpox may be helped by an antiviral medicine, if the illness is diagnosed early enough.

Keep your child off school or nursery until all their spots have crusted over. That helps stop chickenpox spreading. Adults with chickenpox should also stay off work until every spot has crusted over.

Chickenpox is infectious from 1 to 2 days before the rash starts. It stops being infectious once all the blisters have crusted over, which usually happens 5 to 6 days after the rash begins.

If you or your child has chickenpox, try to stay away from public areas. That way you avoid contact with people who may not have had it. Take special care to keep away from people who are at risk of serious problems, such as:

• newborn babies
• pregnant women
• anyone with a weakened immune system (for example, people having cancer treatment or taking steroid tablets)

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

If you are in one of these groups, speak to a doctor as soon as you are exposed to the chickenpox virus or develop chickenpox symptoms.

You may need a blood test to check if you are protected from (immune to) chickenpox.

If you're pregnant, chickenpox can occasionally cause complications. It occurs in approximately 3 in every 1,000 pregnancies.

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 get it during the first 28 weeks, your baby could develop a condition known as foetal varicella syndrome (FVS). This syndrome is rare. FVS can cause serious complications, including:

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

There are other risks from catching chickenpox after week 20 of pregnancy too. Your baby may be born prematurely (before week 37 of the pregnancy).

If you are infected with chickenpox 7 days before or 7 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.

Once you've had chickenpox, you usually develop antibodies to the infection, and that makes you immune to catching it again.

But the virus that causes chickenpox, the varicella-zoster virus, doesn't leave your body. It stays inactive in your nerve tissues, and it can come back later in life as an illness called shingles.

You can catch chickenpox from someone who has shingles, but it doesn't work the other way around.