Overview

Chickenpox, also known as varicella, is an infection caused by varicella-zoster virus (VZV). This virus is part of the herpes viruses, which are very contagious and can be spread from one person to another by direct or indirect contact.¹ Although there are different viral diseases that can cause a rash, a specific characteristic of chickenpox is that the rash goes through different stages, making the person have different lesions at the same time: macules, papules, blisters and scabs.² In this article, we will analyse the different stages of the chickenpox rash.

Start of the infection

Varicella-zoster virus (VZV) is transmitted directly between persons through infected droplets, that are expelled by sneezing or coughing, and impact the mouth or the nose, by touching the lesions in an infected person, or indirectly by touching surfaces that contain the virus.^1,3 Although it is more common in children, you can develop chickenpox as an adult too.³ A person is contagious before the rash appears, and children between 4 to 10 years are at more risk of getting the infection.¹ However, the symptoms can be worse in newborns, adults, and people with a weakened immune system.^2,  

The clinical manifestations start 1 or 2 days before the rash appears and usually get resolved one or two weeks after the infection, with symptoms such as:¹

• Lack of appetite
• Headache
• A general feeling of being unwell
• Runny nose
• Sneezing
• Cough
• High temperature (fever)

In adults, high temperature (fever) tends to be higher than in children, and children might not have any of these symptoms.¹

Stage 1: emergence of the rash

The rash starts as red or pink flat spots (macules) in the skin that are less than 1 cm and are very itchy. The lesions first appear in the face and torso, then they spread to the scalp, arms, legs, and sometimes in gthe enitals or inside the mouth. In children, the lesions can appear inside the mouth first.^1,2 

Stage 2: from macules to papules

While more flat spots (macules) appear, the spots that emerge first start to have a bump in the centre (papules) and start being itchier and becoming brighter. Hence, at this point, the person has two different lesions: macules and papules, which spread out through different parts of the body.^1,2 

Stage 3: from papules to blisters

Papules change to blisters that can burst, are pink, and brighter, and have a clear fluid that turns cloudy inside. Blisters are itchier than macules and papules; they can even be very painful and might be present in genital areas, soles, and palms. Usually, these lesions are more extended in adults, who can have higher fever than children and develop pneumonia.^{1, 2, 3} In this stage, the person has macules, papules, and blisters.

Stage 4: blisters become scabs

Some days later, blisters dry out and scabs start appearing. Some scabs can have a little liquid while others are flaky, and after some time, scabs fall off. The skin is referred to as a starry sky precisely because it has chickenpox rash in different stages.^1,2 

Healing process 

The number of lesions can go from 250-500, but it can vary from one person to another. A lesion tends to heal in 3 to 5 days approximately.^1,2,4 The complete infection passes between 2 to 4 weeks after the beginning of the symptoms.¹ When the scabs fall off, some lesions can leave dark marks- this is known as a temporal hyperpigmentation of the skin. Children and adults can have permanent scars or pockmarks, but they are more common in adults.^1,4

Once a person gets chickenpox, it is uncommon to get it again, but it can happen in some cases.¹ Usually, the reinfection of varicella-zoster virus (VZV) produces shingles (herpes zoster), affecting one limited area of the body with the presence of rash and blisters. This can happen even years after the first infection of the virus.^4,5

Diagnosis

Chickenpox, like other viral exanthems, is associated with the characteristics of the lesions in the skin, the presence of fever, and other symptoms.⁵ Therefore, the diagnosis requires an interrogation about the evolution of the symptoms and a physical exploration of the lesions.¹ If it is possible, warn your doctor that it is a possible case of chickenpox before going to the medical revision, as it is a very contagious disease.

Viral exanthems can be very similar at the first stages, hence, it is important to look for medical help if there is doubt about the symptoms or the rash that the person is experiencing. When the diagnosis is confused some tests, such as polymerase chain reaction (PCR) or blood tests, are required.^1,2,4

Treatment

As well as in other viral exanthems, in chickenpox, the initial treatment is directed to mitigate the symptoms. The next general measures that can help to deal with the infection are as follows:^3,4,5

• The person with chickenpox must be isolated: children for at least 5 days and adults, depending on the severity, between 7 to 14 days
• It is crucial to avoid contact with children, pregnant females, newborn babies, or people with a weak immune system
• Paracetamol is helpful in diminishing the pain- do not use other painkillers without asking your doctor
• To reduce the itch, it can be necessary to use oral antihistamines and lotions or creams on the lesions
• Drink abundant liquids to prevent dehydration
• Take baths with warm water, it is important to pat and avoid rubbing to dry the skin
• Wear light and loose clothes
• Do not scratch the lesions
• In children, it is important to cut their fingernails and to use socks on their hands at night with the aim of avoiding scratches

Complications

There are various complications that can occur because of chickenpox, and we will analyse some of the most common ones below.

Bacterial infection

A secondary bacterial infection can occur through the scratching of the lesions and not washing hands adequately. Some of these infections are impetigo, cellulitis, and erysipelas.^{1, 3}

Pneumonia

When the infection is severe, it can spread to the lungs, causing pneumonia. This complication is uncommon in children, but it might be presented in circa 14% of the cases in adults.^2,3

Chickenpox during pregnancy and newborn

An infection of chickenpox during pregnancy can have serious consequences for the baby. If the infection is at the beginning, the baby can have malformations. If the infection occurs close to childbirth, or in newborns, it can be fatal because their immune system is not completely developed to fight against the virus.^2,4

Complications in the central nervous system

Complications in the central nervous system due to chickenpox are very rare. Nevertheless, in people with a weakened immune system, for example, with AIDS or cancer, complications such as meningitis or encephalitis can happen.

Prevention

The chickenpox vaccine is very effective in preventing the disease. If someone vaccinated gets the infection, the symptoms are mild with fewer lesions than without the vaccine.⁴ In the UK, this vaccine is available in the NHS only when people are at high risk of having the disease, for example, in healthcare personnel. However, it can be obtained as a private service. 

It is also important to remember that isolating patients with chickenpox is essential to stop the spread of the contagion.⁴ Depending on the evolution of the lesions, which need to be dried up, and the characteristics of the persons, this isolation must be between 5 to 14 days.^{1,2, 3}

Summary

There are different viral infections that can produce rash, and all of them have different characteristics that help form a diagnosis. In the case of chickenpox, the lesions go through different stages and new lesions appear, while the others change. To help your doctor achieve a diagnosis, it is important to give all the information about the evolution of the symptoms, as well as the evolution of the different stages of the chickenpox rash if it is possible. In addition, remember that isolating the person with this disease is crucial to stop the spread, mainly if they have close contact with pregnant females, newborns, or people with a weakened immune system. Finally, remember that vaccination is effective against chickenpox, and it can help to stop the spread of the disease too.