Introduction

Chickenpox is a highly contagious viral infection that mainly affects children. Typical symptoms include a very itchy skin rash with red blisters and a mild fever. Because most children are now vaccinated, chickenpox (also known as varicella) is much less common than it was in the past.

If someone becomes infected with chickenpox, they are contagious after just one or two days, which is before they have a visible rash. Taking precautions and paying attention to hygiene can help to avoid infecting others. Although chickenpox is unpleasant, it rarely has any serious consequences in children who are otherwise healthy. But it may be more severe in newborns and adults, as well as people who have a weakened immune system.

At a glance

• Chickenpox causes a very itchy rash and a mild fever.
• This viral infection is most common in children.
• It is spread through tiny drops of saliva (spit) or direct physical contact.
• Vaccines prevent infection.
• Chickenpox is often more severe in adults than in children.

Symptoms

People who get chickenpox generally feel ill at first. It causes muscle pain and headache, and your body temperature rises. The itchy rash typical of chickenpox develops next – usually on your face and torso first, and later spreading to your scalp, arms and legs. Sometimes mucous membranes and the genitals are also affected. The extreme itching is often the main problem, making it hard to sleep. Adults who have chickenpox may not develop a rash, or it may not spread over their body in the same way as it does in children.

The fever lasts three to five days, but is rarely higher than 39 °C (about 102 °F). The rash starts as small red spots and bumps, which then turn into blisters. The blisters contain clear fluid that later turns cloudy. They dry up after a few days. Scabs form and soon fall off. It usually takes about three to five days for the blisters to heal. Because the blisters on the skin are in different stages of development at any given time, their distribution is sometimes described as a “starry sky.” The total number of blisters varies widely from person to person.

Baby with a typical chickenpox rash. Below: Development of a chickenpox blister

Causes

Chickenpox is caused by the varicella-zoster virus, which is one of the herpes viruses. These viruses spread from one person to another through droplets or direct contact. When someone who is contagious breathes, coughs, sneezes or speaks, tiny droplets of saliva (spit) are released into the air. Chickenpox is usually spread when people breathe in those droplets. Fluid from inside the blisters is also contagious if they break open or are scratched off. Almost any contact with someone who has chickenpox leads to infection – unless you are either vaccinated or have already had chickenpox yourself.

Prevalence

Chickenpox is most likely to affect preschool and school-age children between the ages of 2 and 10. Older children or adults who haven’t been vaccinated can also become infected if they didn’t have chickenpox when they were younger.

As of 2004, chickenpox vaccinations have been recommended by the German Standing Committee on Vaccination (STIKO) at the Robert Koch Institute. Because most parents now follow this recommendation, the number of chickenpox cases has fallen considerably:

• Before 2004, about 750,000 children and adults got chickenpox in Germany every year.
• In 2020, about 11,300 cases of chickenpox were reported – which is about half as many as in the year before that. More than 90% of the people who had chickenpox hadn’t been vaccinated.

But chickenpox is still one of the most common childhood diseases.

Outlook

After being infected, it usually takes about two weeks for the symptoms to start. The first symptoms may already appear one week after infection, but it can take as long as three weeks too (incubation period). In most children, chickenpox goes away again within two weeks.

Chickenpox: Outlook and infectious period

Adults who come down with chickenpox often have a more difficult time than children. The disease may last longer and make them feel more ill. The risk of developing complications is also higher in adults.

If you have already had chickenpox once, you are immune to it for life. So you can only get it once.

Effects

Breaking the itchy blisters open by scratching them may lead to a bacterial infection in the skin and leave scars. The risk of scarring is lowest if the scabs just fall off on their own. The amount of scarring will also depend on the size of the blisters.

The virus can also lead to pneumonia in adults with very severe cases of chickenpox. Very rarely the viruses may attack the central nervous system, resulting in meningitis or encephalitis. The risk of this happening is greater in people with a weakened immune system, for instance due to cancer, AIDS or another serious disease.

Once chickenpox has gone away, the varicella-zoster viruses are inactive but they stay in the body. The viruses may become active again many years later, leading to shingles. This condition causes a skin rash that can be very painful. It is most common in older people and people who have a weakened immune system. Adults with shingles can infect others who are not immune to the virus. Those people then develop chickenpox.

If a woman gets chickenpox within the first six weeks of pregnancy, the viruses can cause serious abnormalities in the unborn baby. A chickenpox infection close to a baby's due date can be life-threatening to the baby, whose immune system is not yet developed enough to fight off the viruses.

Diagnosis

Doctors can usually diagnose chickenpox based on the typical rash. Sometimes blood or blister fluid is tested for the virus, but only if the disease is developing in an unusual way. Your blood can be tested for antibodies to find out whether you have already had chickenpox and are immune. This may be necessary in pregnant women.

Prevention

The vaccination recommendations issued by the German Standing Committee on Vaccination (STIKO) apply to all children over eleven months of age, but also include the following groups, provided they have not had chickenpox already: teenagers, women hoping to get pregnant, and people who have certain other conditions such as severe eczema. In Germany, chickenpox vaccinations are covered by statutory health insurers. The vaccination consists of two injections given at least four to six weeks apart.

If you have never had chickenpox and are not vaccinated, you can still get vaccinated within five days of coming into contact with someone who is infected. Doing that can stop you from developing chickenpox, or at least help make the symptoms milder.

Vaccinations should no longer be given during pregnancy. If a pregnant woman is at risk of infection, she can have treatment with antibodies to fight the viruses. This is called passive immunization, and it is also an option for newborns if their mother develops chickenpox a few days before or after the birth.

People who have been immunized can still get chickenpox. That rarely happens, though, and then the symptoms are usually milder. There is also a lower risk of complications.

Chickenpox is classified as a notifiable disease in Germany. This means that all doctors must inform their local health authority even if someone is only thought to have chickenpox. If a child is infected, the health authority might then contact the parents to tell them to keep the child at home until he or she is no longer contagious.

Anyone who has chickenpox should avoid direct contact with other people as much as possible – unless it's known that they've already had it. You should be especially careful around pregnant women and people who are at greater risk of having more severe chickenpox.

Treatment

Usually only the symptoms of chickenpox are treated. In more severe cases, or if there is a greater risk of complications, antiviral drugs can be used to fight off the virus. Lotions, gels and powders are often applied to the skin in order to relieve the itching and dry out the blisters. Most of them contain tanins, zinc, menthol or polidocanol. Sometimes oral medications like antihistamines are also recommended to stop the itching. But there is no good-quality scientific research on how effective these treatments are.

Symptoms like fever or joint pain can be relieved using medicine that contains acetaminophen (paracetamol). The painkiller ibuprofen is not suitable for children with chickenpox.

Box

Children and teenagers should not take acetylsalicylic acid (the drug in medicines like Aspirin) unless their doctor says they can, if other things haven’t helped. It can cause a rare but dangerous side effect called Reye’s syndrome in (more...)

Everyday life

It can be very difficult not to scratch the itchy areas of skin. But it’s still important to avoid scratching because the fluid in the blisters is contagious. Plus, blisters that have been scratched open tend to scar. It can help to keep children’s fingernails trimmed, or put cotton mittens on babies’ hands to make it harder for them to scratch themselves. Wearing loose-fitting clothing made of smooth fabrics can help prevent further skin irritation.

Having a shower is generally better than taking a long bath because then your skin doesn’t absorb as much water. It is best to carefully pat your skin dry after having a shower or washing yourself.

Further information

When people are ill or need medical advice, they usually go to see their family doctor first. In our "Health care in Germany" topic you can read about how to find the right doctor – and our list of questions can help you to prepare for your appointment.

Sources

• Bundeszentrale für gesundheitliche Aufklärung (BZGA). Infektionsschutz​.de. Windpocken / Gürtelrose: Informationen über Krankheitserreger beim Menschen – Impfen schützt! 2019.
• Macartney K, Heywood A, McIntyre P. Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults. Cochrane Database Syst Rev 2014; (6): CD001833. [PMC free article: PMC7061782] [PubMed: 24954057]
• Robert Koch-Institut (RKI). Empfehlungen der Ständigen Impfkommission (STIKO) am Robert Koch-Institut (Epidemiologisches Bulletin 4/2022). 2022.
• Robert Koch-Institut (RKI). Infektionsepidemiologisches Jahrbuch meldepflichtiger Krankheiten für 2020. 2021.
• Robert Koch-Institut (RKI). RKI-Ratgeber: Varizellen (Windpocken), Herpes zoster (Gürtelrose). 2017.
• Robert Koch-Institut (RKI). Schutzimpfung gegen Windpocken (Varizellen): Antworten auf häufig gestellte Fragen. 2021.
• Siedler A, Arndt U. Impact of the routine varicella vaccination programme on varicella epidemiology in Germany. Euro Surveill 2010; 15(13): pii: 19530. [PubMed: 20394710]

• IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

  Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

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