Introduction

Chickenpox (also known as varicella) is a highly contagious infection caused by the Varicella-Zoster Virus (VZV). It is characterised by a red rash on the skin that develops itchy blisters on which scabs form over. 

This virus primarily affects the mucosa of the upper airways (nose through to the larynx). Your immune system develops antibodies to provide immunity against VZV. VZV then becomes latent, but it can reactivate later to cause shingles (herpes zoster).¹ 

Chickenpox can be spread in several ways: through body contact, by breathing in air from coughs or sneezes, or by coming in contact with fluids from someone infected. 

This disease most commonly affects children 4 to 10 years of age, leading to the administration of vaccines at a young age.¹ This has helped to prevent both the cases and complications that arise as a result of chickenpox. 

In the majority of cases, the virus affects those who have not been exposed to it before or have not been vaccinated against it. Adults who contract it can suffer from severe consequences, particularly during pregnancy. Chickenpox can have serious health implications for you and can also have a negative impact on your baby.

Signs and symptoms of chickenpox 

The following are some of the initial symptoms of chickenpox:¹

• Fever 
• Fatigue 
• Headache
• Muscle or body ache
• Reduced appetite
• Nausea
• Pharyngitis (sore throat)

Then, a skin rash begins to develop on the face, chest and back, spreading throughout the body. Stages of the skin rash include:

• Red and bumpy rash (lasts a few days)
• Fluid filled blistered rash (breaks open after a day or so)
• Scab forms over the blisters (also lasts for a few days)

These signs and symptoms of chickenpox tend to appear 10-21 days after exposure, however, they only last for 5-7 days.¹

There can be complications associated with chickenpox in severe cases, such as:

• Pneumonia (chest infection)
• Bacterial skin infections
• Encephalitis (inflammation of the brain)
• Dehydration
• Liver issues 

Complications associated with chickenpox are more common among adults than children. Pregnant people who have not previously had chickenpox are especially vulnerable to these complications.¹

Chickenpox in pregnancy

During pregnancy, most people are usually immune to chickenpox as they have previously had the infection and therefore developed antibodies against it, or had the vaccine for it. However, if they haven’t had either of these, they are at risk for developing chickenpox and the complications associated with it during pregnancy. 

In countries with temperate (cooler) climates, around 90% of people of child-bearing age are usually immune to chickenpox. In tropical (warmer) climates, more people tend to not be immune to chickenpox.² Therefore, it is important to know whether you are immune to chickenpox if you are pregnant or planning to have children. Management strategies can be implemented early to avoid risks to yourself and your foetus during pregnancy.

When a pregnant person becomes infected with chickenpox, the most common health issue they tend to experience is maternal varicella pneumonia.³ This can cause them to experience breathing difficulties. 

If this occurs you must be hospitalised. You and your pregnancy can be monitored and you will receive antiviral therapies. 

As gestational age increases, so does the severity risk of maternal varicella pneumonia.³ This issue can lead to difficulties during delivery which include intrauterine growth restriction and low birth weight.^2,3

Risks to the foetus and newborn

When chickenpox is contracted during pregnancy, it can cause congenital varicella syndrome (CVS) and neonatal varicella which affects the foetus. Both conditions are associated with a high mortality and morbidity rate.^2,4

Congenital varicella syndrome (CVS)

When a pregnant person gets chickenpox during the first half of their pregnancy, CVS occurs. The varicella infection can infect the foetus via the placenta.^1,4 The risk of CVS is at its highest between 13th-20th weeks of gestation.⁴ This syndrome can lead to defects in newborns across several parts of the body such as the skin, limbs, eyes, central nervous system (CNS) and autonomic nervous system (ANS). Symptoms include:^1,2,4

• Scarring skin lesions
• Underdeveloped toes and fingers
• Structural eye damage
• Neurological disorders
• Anal and bladder malformation
• Developmental delay

Newborns who survive from CVS may also experience long term learning difficulties and developmental problems.^2,4

Neonatal varicella

Neonatal varicella can take place when the foetus becomes infected days before delivery or the newborn gets directly infected during the first few weeks of life.⁴ 

Neonatal varicella can be life threatening. A condition known as high viremia occurs, which is where the newborn's immune response isn't sufficient enough to prevent the spread of the VZV and produce antibodies against it.^2,4 

It is especially dangerous for babies born at less than 28 weeks of gestation and weigh less than 1000 grams.. This is because they have less protection with only antibodies from the mother, which increases their risk of infection leading to chicken pox.² 

Newborns with this condition are at a high risk of pneumonia and other serious complications.^1,2,4,5 Clinical features of neonatal varicella include:

• Fever 
• Rash that develops into lesions that eventually crust off

In rare cases infants develop this disease with:

• Pneumonia 
• Hepatitis
• Thrombocytopenia

Diagnosis of chickenpox

The most common way to diagnose chickenpox is through clinical assessments and physical exams. Healthcare professionals will examine you for initial symptoms like fever and headache, as well as signs of a rash, when visiting. However, laboratory tests are sometimes necessary to confirm some cases of chickenpox when they are rarer or more severe. Tests that may be used include:¹

• PCR (polymerase chain reaction) test - used to detect the DNA of VZV indicating if you have been infected
• Fluid test - involves examining the fluid from the blisters 
• Blood test - used to identify antibodies which indicate a VZV infection

CVS can be diagnosed by:⁴

• Observing the appearance of chickenpox 
• Identifying viral DNA in the newborn from VZV infection
• Identifying the presence of chickenpox antibodies in the newborn 

Also, neonatal varicella can be diagnosed based on:^4,5

• Appearance of skin lesions on the newborn
• Whether the mother starts to develop clinical symptoms close to the time of delivery

Prevention and management of chickenpox

Preventive measures

The main way chickenpox has been controlled over the years is through the varicella vaccination. It is able to prevent 70-90% of infections and 95% of severe diseases from occurring.^1,6 

It is encouraged to have the vaccination before getting pregnant if you haven’t had chickenpox. It will help avoid risks to the pregnant parent and foetus if the infection is caught during pregnancy, as the vaccine can’t be administered when pregnant. 

Prevention of chickenpox during pregnancy can also be aided by going in for antenatal screenings. This can identify early in pregnancy if you are uncertain about having been infected before. If you are susceptible to chickenpox, management can be put in place to avoid risk of infection.

Treatment options during pregnancy

Treatments are in place to provide relief of the symptoms of chickenpox.¹ 

Antiviral medications 

• Acyclovir (given to children, adults and pregnant women)
• Valacyclovir (Valtrex) 
• Famciclovir

These are orally administered in normal cases of chickenpox, and intravenously administered in severe cases, or for newborns.²

Varicella-zoster immune globulin (VZIG) 

• Given in combination with acyclovir when managing chickenpox in pregnancy

These treatments help with dealing with chickenpox generally and during pregnancy as well, reducing mortality rates. They also apply as treatments for CVS and neonatal varicella.⁵

Managing symptoms 

Alongside treatments, there are actions you can take to help manage your symptoms:¹

• Avoid scratching to prevent worsening of the symptoms
• Apply topical calamine lotion for relief, to reduce dryness, and to prevent itching
• Daily cleansing with warm water to avoid bacterial skin infections
• Paracetamol for fever
• Trim nails to prevent scratching

Summary

To conclude, chickenpox is a viral infection caused by varicella-zoster virus. It’s an infection that can easily be spread among people, more easily in children, mainly through inhaling or touch. The varicella vaccination is available to control chickenpox which is encouraged to be administered at a young age. Chickenpox is not usually dangerous unless you become infected as an adult. If you are or plan on becoming pregnant, it is important to protect yourself from developing chickenpox as it can cause severe complications to yourself as well as your baby. So, it’s vital to be aware of chickenpox before getting pregnant if you have never had it before or been vaccinated against it.