Chickenpox is caused by infection with herpes zoster virus. The medical name for chickenpox is varicella. Chickenpox is infectious, and you can catch chickenpox by coming into close contact with someone who has it. The symptoms of chickenpox start to show between 10 days and three weeks after catching it. They start with a temperature and feeling unwell, followed by the appearance of watery itchy blisters, which burst, crust over and then heal. Chickenpox is infectious for two days before the blisters appear and until the last blister has crusted over, which is usually about two weeks.
If you have had chickenpox in the past, then you cannot catch it again (you are immune).
If you have never had chickenpox, or are not sure, there is a blood test to find out whether you are immune. If you are not immune, there is an injection called Varicella Zoster Immune Globulin (VZIG). This is a human blood product and can strengthen your body’s immune system, but does not guarantee that you will not catch chickenpox. The VZIG injection can be given up to ten days after a contact with chickenpox. It does not work once the chickenpox blisters have appeared.
Chickenpox during pregnancy can result in a severe infection. Treatment with acyclovir, an anti-viral drug, can reduce the fever and symptoms. Acyclovir is not recommended before 20 weeks.
You are infectious and should tell any pregnant women that you have been in contact with that you have been diagnosed with chickenpox.
Chickenpox in pregnancy can be very severe. Complications can develop such as pneumonia, liver inflammation (hepatitis) and brain inflammation (encephalitis).
Signs of severe infection are chest and breathing problems, headache, drowsiness, vomiting or feeling sick, vaginal bleeding, a rash that is bleeding. These symptoms may be a sign that you are developing the complications of chickenpox.
If you need to be admitted to hospital, you will be nursed in a side room away from other babies and pregnant women.
There is no treatment that will prevent your baby catching chickenpox while inside the womb.
The baby will have some protection from your immunity, but there is a chance that your baby will catch chickenpox while inside the womb. Before 20 weeks, the baby’s organs are still forming. If the baby catches chickenpox, there is a 1-2% chance of birth defects affecting legs, arms, brain, eyes, bladder and bowel. You should be referred to a Fetal Medicine Unit for detailed scans of the baby and a discussion of the risks.
The baby is fully formed after 20 weeks, so the risk of birth defects is almost nil.
The baby may catch chicken pox inside the womb and there may be pox blisters or scars on the baby’s skin when the baby is born.
If the baby is born while you have chickenpox, the baby will no longer have the benefit of your immunity and the baby may get a severe chickenpox infection. The baby’s immune system can be boosted with the VZIG injection. If the baby catches chickenpox, the baby can be treated with the anti-viral drug acyclovir.
It is safe to breastfeed if you have chickenpox or have had chickenpox in your pregnancy.
Shingles is caused by re-activation of the chickenpox virus in the body. It presents as a rash on the skin, often on the chest or abdomen. It is less infectious than chickenpox. If you are immune to chickenpox, then it is not possible to catch shingles from somebody who has it.
If you are not immune to chickenpox, it would be possible for you to contract chickenpox if you came into close contact with the vesicles.
If your baby has had chickenpox, then they are immune, but could develop shingles later on.