Patient information from BMJ

Chickenpox

Last published:Dec 01, 2023

Chickenpox is an infection that causes an itchy rash. It usually goes away after a week or so, but it can make some people seriously ill.

What is chickenpox?

Chickenpox is caused by a virus called varicella zoster. It's passed from person to person easily. You can pass it on to other people for a day or two before you even know you have it. Most people get chickenpox as children. Once you've had it, you can't usually get it again.

What are the symptoms?

The main symptom of chickenpox is an itchy red rash, mainly on the body and the face. You may also feel generally unwell and have a fever (a high temperature).

At first you'll get itchy spots that are filled with fluid. After a few days the spots will turn into scabs. They don’t usually leave a scar unless they get infected. This can happen if you scratch them.

What should I do if my child has chickenpox?

Children usually recover from chickenpox on their own. Some parents use calamine lotion on their child to try to ease the itching. But there isn't any good evidence to show that it really helps. Try to keep your child drinking plenty of fluids so they stay hydrated.

You can give some medicines to help if your child is in pain or has a fever. Paracetamol (or paracetamol syrup for young children) is most commonly used. It is important that you do not give ibuprofen as it may increase the risk of serious bacterial skin infections when given to people with chickenpox. It is also important that you do not give aspirin to your child if they are under 16.

Most children are better in a week to 10 days. Your child will probably need to miss about a week of school. Talk to your doctor if you're worried about your child for any reason.

What if I'm pregnant?

If you're pregnant and you come into contact with someone who has chickenpox, you don’t need to worry as long as you've been vaccinated or you've had chickenpox before.

If you haven't, see a doctor straight away. The doctor can do a test to see if you are immune to chickenpox: for example, if you are not sure whether you had it as a child.

If you get chickenpox during pregnancy your doctor might recommend an you are given antiviral medicines.

Most women who get chickenpox while pregnant have a healthy baby. But if you get it during the first six months of pregnancy there is a small chance it could harm your baby.

About 1 in 100 babies whose mothers had chickenpox during this time have underdeveloped arms or legs, brain damage, or eye problems.[1]​

If you get chickenpox late in your pregnancy, especially around the time you have your baby, your baby could develop chickenpox. See a doctor if you get chickenpox while pregnant or soon after giving birth.

What treatments are available?

Most children don't need treatment for chickenpox. For teenagers, adults, older people, very young babies, pregnant women, or people with a weak immune system, chickenpox can be more serious.

If you have a weakened immune system (for example, if you are having chemotherapy treatment for cancer or are taking other medicines that affect your immune system), see a doctor as soon as you can after coming into contact with someone who has chickenpox. You should also see a doctor if you are pregnant or if you think your newborn baby may have chickenpox.

You may be given antiviral medicines to help to fight the chickenpox virus. These medicines are usually given as tablets.

The chickenpox vaccine

A vaccine can help prevent chickenpox, but not all countries include it in the normal vaccinations given to children.

The vaccine is recommended for certain people if they haven't previously had chickenpox or the vaccine. This includes healthcare workers and people in contact with someone with a weak immune system (for example, someone who has a sister or brother with leukaemia).

If you're thinking of getting pregnant and have not had chickenpox before, you may want to ask your doctor about the vaccine.

What to expect in the future?

Most people get better from chickenpox without any treatment. But the virus that causes chickenpox stays in your body after you get it.

Some people who've had chickenpox get shingles later in their lives. Shingles is a painful rash around the body and face, which sometimes affects the eyes. It happens when the chickenpox virus starts reproducing in your nerve cells.

For more information see our leaflets: Shingles: what is it? and Shingles: what treatments work?

Chickenpox can be more serious for adults, babies, or people with a weak immune system. Sometimes the rash gets infected, or people lose too much fluid (dehydration). Some go on to get other illnesses such as a serious lung infection (pneumonia), nerve damage, and liver damage.

Most airlines won't let people travel while they have chickenpox.

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