Chickenpox – Definition, symptoms and treatment

DocFinder, Shutterstock
DocFinder, Shutterstock

Chickenpox (also known as varicella) is a highly contagious viral infection. Although it primarily occurs during childhood, the disease can also affect adults. The characteristic symptoms are fluid- filled blisters and extreme itchiness. In most cases, the illness runs its course without any complications – though it can, in some cases, lead to serious secondary illnesses. Contagion, symptoms, possible complications, prevention and treatment – read on for all the key info about chickenpox.

What is chickenpox?

A well-known and distinctive disease, chickenpox primarily occurs during childhood and is caused by an infection with the highly contagious varicella zoster virus (VZV). The varicella zoster virus belongs to a group of herpesviruses that also includes the herpes simplex virus – the virus behind herpes simplex infections in humans (in the form of oral or genital herpes). As well as chickenpox, the varicella zoster virus is also the cause of shingles. Chickenpox is highly contagious. The varicella zoster virus is passed on through droplet or smear infection. In the case of droplet infection, the virus is transmitted through tiny respiratory droplets that are produced when an infected person speaks, coughs or sneezes and are ingested by others who breathe in that air. A smear infection denotes transmission of the disease through contact with the fluid in the blisters on the infected person’s skin. The incubation period – the name for the time between contracting the virus and appearance of the first symptoms / onset of the disease – is around 12 to 21 days. Furthermore, while rare, it is possible that a mother could pass the disease on to her unborn child via the placenta. If a mother-to-be contracts the varicella zoster virus for the first time during the first 20 weeks of pregnancy, it can cause the unborn child to develop deformities (congenital varicella syndrome).

Link between chickenpox and shingles

While most people contract chickenpox as a child, it is possible to develop the disease at any age. Anyone who had chickenpox as a child is immune for life – so, as a general rule, a person can only have chickenpox once. However, even after the illness recedes, the virus remains in the body. The virus retreats to the spinal ganglia, where it remains dormant for the rest of the person’s life. In certain circumstances, the virus may reactivate at a later date. If the virus does reactivate, the result is shingles: the characteristic symptom of this infection is a belt-like rash with fluid-filled blisters. The primary infection with varicella zoster virus therefore leads to chickenpox, with shingles being the secondary illness caused by the virus. As a result, only people who have already had chickenpox can develop shingles. If someone suffering from shingles infects another person with the varicella zoster virus, they will develop chickenpox if they have not already had it or been vaccinated against it.

Rash and extreme itchiness – chickenpox symptoms

The characteristic symptom of chickenpox is a rash with fluid-filled blisters. The first indications are often quite general symptoms such as feeling unwell, lethargy, headaches and aching limbs. The typical rash then develops from around the third to fifth day of the illness. Small red blotches form and soon develop blisters that are filled with a clear fluid. In most cases, the blisters first appear on the face and torso before later developing around the mucous membranes and on the arms, legs and scalp. These blisters are accompanied by extreme itchiness and, quite often, a high fever (though rarely above 39°C). After a few days, the blisters dry out and crust over before eventually falling off. Scratching the blisters and contracting an additional bacterial infection can result in lasting scars. Once all of the blisters have crusted over, the infected person is no longer contagious. Most of the time, the blisters heal completely without scarring; in people who are otherwise in good health, the disease usually runs its course without complications. In some cases, however, it can lead to complications and secondary diseases. One common complication of varicella is bacterial superinfection (in which the blisters develop a bacterial infection). Other more serious complications include lung infection (varicella pneumonia), complications relating to the central nervous system, encephalitis (inflammation of the brain) and conditions in which other organs become inflamed, such as myocarditis (heart), nephritis (kidneys), arthritis (joints) and keratitis (cornea). While chickenpox is less common in adults, the disease is often more serious than it is for children. The risk of complications is also higher for adults than for children, with pregnant women and immunodeficient people at particular risk of serious illness. Adults usually complain of a more pronounced feeling of being unwell and in most cases develop more blisters than children. The course of the disease is also somewhat longer than in children. In children, the illness lasts around ten days to two weeks. Adults can develop chickenpox if they have never previously had the disease and have not been vaccinated against it.


The chickenpox vaccine is the best way to avoid catching the disease. The Austrian Vaccination Programme recommends that children receive their first vaccination around their first birthday, with the second at least 4 weeks later – but before they start to attend community facilities (e.g. nursery or kindergarten). The chickenpox vaccine is not part of the free vaccination programme in Austria. Active immunisation is recommended for 9 to 17-year-olds in particular (and is known as catch-up vaccination). For adults, immunisation is recommended for all people susceptible to the illness, especially non-immune women of childbearing age (i.e. who do not have antibodies against specific antigens in their blood), childcare personnel susceptible to illness and non-immune people who work in the healthcare system. People who have not been vaccinated should avoid contact with people infected with the disease. Another option is passive immunisation (varicella zoster immunoglobulin – VZIG), which can prevent or relieve the onset of the disease and should be used when active chickenpox vaccination is not possible. It is recommended that VZIG is administered to at-risk people with weak immune systems and vaccinated pregnant women who do not demonstrate immunity as soon as possible following exposure to the disease (within 96 hours).


When the disease runs its course without complications, treatment essentially involves alleviating the symptoms. Antipruritic remedies can help to relieve the extreme itchiness when applied to the relevant areas of skin. These creams, lotions, gels and powders are applied to the blisters directly and relieve the itchiness for a few hours. Furthermore, antipyretic medications and analgesics can be used where necessary to treat the fever – though it is always advisable to consult a doctor first (and exercise caution when giving acetylsalicylic acid to children and young people as there is a risk of Reye syndrome).

The extreme itchiness is worsened by heat and sweat, which is why doctors recommend maintaining a pleasant room temperature and wearing breathable clothing. It is important to avoid scratching the itchy blisters as doing so can result in bacterial infections and scarring. In this regard, it can be helpful to keep finger nails cut short and to wear woollen gloves or mittens. Antibiotics have no effect on varicella; however, they may be prescribed if the blisters that have been scratched open become

infected (bacterial superinfection). In severe cases, the virus can be treated with specific medication: so-called virostatic agents, which prevent the viruses from reproducing and can prevent the illness from worsening, are primarily prescribed for patients with a weakened immune system.

Fact box

Chickenpox: Viral disease
Other names: Varicella
Pathogen: Varicella zoster virus (VZV; primary illness is chickenpox; secondary illness is shingles)
Transmission: Droplet and smear infection, during pregnancy (rare)
Incubation period: Around 12 to 21 days
Symptoms: To begin with, general symptoms occur such as feeling unwell, lethargy, headache and other aches and pains, before a rash develops with fluid-filled blisters (starting on the face and torso before developing on the mucous membranes, arms, legs and scalp), extreme itchiness, fever, among others
Contagiousness: Ends when all blisters have crusted over
Potential complications / secondary diseases: Bacterial superinfection (additional bacterial inflammation of the blisters), pneumonia, complications relating to the central nervous system and other organs; frequent or repeated scratching and bacterial superinfection can result in scarring
Prevention: Vaccination, avoiding contact with people carrying the disease Treatment: Antipruritic remedies for targeted application; in some circumstances, antibiotics to treat bacterial superinfection, virostatic agents (for serious cases, patients with weakened immune system)

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Autor: Katharina Miedzinska, MSc