Everything you need to know about chickenpox


09. 04. 2019

What is the difference between chickenpox and smallpox? What is the diseases incubation time? How is it transmitted, how does it manifest, how does it heal? Canadian Medical’s pediatrician, Dr. Petr Žáček, answers your questions. 

Chickenpox, also known as varicella in the scientific community, is a highly contagious viral disease, most commonly contracted by young children. It is caused by the initial infection with the varicella zoster virus (HHV-3) of the Herpesviridae family. The sole hosts of the virus (i.e. the only ones that can become ill) are humans. 

Smallpox, also known as variola, is an acute and highly contagious disease caused by a virus from the Poxviridae family. Smallpox was historically one for the most dangerous and life-threatening infections with a very high mortality. 

In the 20th century, when a large part of today’s population was born, smallpox was the cause of death of more than 300 million people. Even towards the end of the 1960s, 15 million people had fallen ill due to the virus, and 2 million died as a consequence. On the 8th of May, 1980, smallpox was declared as eradicated, by the World Health Organisation (WHO), thanks to the implementation of an intense vaccination program. However, after the end of this vaccination program, the new generations are no longer immune to the variola virus, which still most likely exists in some laboratories. 

This is a topic of conversation that needs to be talked about in society, especially taking into account the currently trending “anti-vaccine movement”. 


How does the disease manifest? 

The varicella (chickenpox) virus is transmitted through droplets in the air, or by direct contact with an infected individual. The virus is most commonly contracted by children of ages between 4 and 8. The incubation period is 10-21 days and following that, the first non-specific symptoms called prodromas may be reported by the patient, indicating the onset of the disease. These prodromas are not so common in young children, and are usually more prominent in children over the ages of 10, and can be severe in adults who contract the disease. Symptoms may include: fever, headache, digestive issues, and sometimes itchy skin. In most cases, headaches and fever usually signify the onset of chickenpox 24-36 hours before the first blisters appear, at which point the patient becomes infectious. These prodromas precede most clinical symptoms by 3-4 days. 


Rash and blistering

Chickenpox is characterised by a rash of itchy blisters about 2-3 mm large, which after a few days become filled with a clear fluid that later becomes milky. These “mature” blisters are 3-6mm in size and produce a crust within the span of 6-8 hours. The rash typically starts on the head, from where it gradually spreads throughout the trunk and to the limbs, but can also appear on the nasopharynx mucosa, the upper respiratory mucosa, the rectum, vagina or the eyelids and conjunctiva. The appearance of blisters occurs in waves with intervals of 3-5 days, so it is not uncommon to see the simultaneous occurrence of various stages of rash- with some blisters already healed and others still forming. 

The acute phase of the disease usually lasts 4-7 days, and the skin blisters heal within 20 days. Only after the crust forms on all the blisters does the patient cease to be infectious. The virus also passes through the placenta, making fetal infection possible which may lead to severe birth defects. In newborns, chickenpox can develop in a progressive varicella, which involves various organs, including the central nervous system. 


How is chickenpox treated? 

Chickenpox heals without any treatment, so it is usually enough to control the symptoms. Because the disease is caused by a virus, it cannot be treated antibiotics, however, even antiviral therapy isn’t necessary in most cases, and is only administered to patients with complications, or in patients with severe underlying health conditions that would otherwise complicate the prognosis. People with very low immunity may be given ready-made varicella virus antibodies (human varicella zoster immunoglobulin) or medication against the herpes viruses. 


Talcum powders - yes or no? 

The treatment for chickenpox is only a symptomatic therapy. When treating the fever with antipyretics, we refrain from giving children salicylates, for the risk of developing Reye’s syndrome. Oral antihistamines (anti-allergy medication) are administered to ease the itchiness of the blisters. The blisters themselves are not treated, that is, not until they rupture, which usually occurs within one or two days, after which they can be treated with drying and disinfecting lotions or creams.  

Powders, even in liquid form, are not suitable for treatment. After their application to the blisters, a crust forms which prevents the skin underneath from healing properly. If a secondary infection of the damaged skin occurs, antibiotic ointments can be used, however for the most part, the blistered skin should be allowed to breathe freely, which aids the healing process. 


Is there a vaccine against the varicella virus? 

Yes, there is an effective vaccine against the disease, however, it is not currently part of the routine vaccinations list. It is suitable for adolescents who did not contract chickenpox during their childhood, and children with a severe underlying condition that could make chickenpox complicated. 

And what about adults? Is there a point in getting vaccinated? Vaccination of adults who have not yet had chickenpox is highly appropriate, especially for health professionals or teachers who are at the highest risk of becoming infected. In the Czech Republic, varicella vaccination is voluntary, and some health insurance companies may contribute to it from their preventative packages. Children over the age of one as well as adults may receive a vaccination, that is administered in two doses within six weeks. In children under the age of 13, the vaccination is almost 100% effective, whereas in adults the protection is about 90%. 


Complications associated with chickenpox

The most common complication that may occur in and individual infected with chickenpox is a secondary infection, caused mainly by the staphylococci and streptococci bacteria. The patient often contaminates and spreads the infection themselves by scratching the blistered areas. A rare complication of chickenpox is cerebellitis (cerebellar ataxia), which involves the central nervous system and occurs within a week from the appearance of the rash, or generalized encephalitis, or aseptic meningitis. In immunocompromised individuals, severe complications may occur, such as varicelitis, meningoencephalitis or hepatitis. Chickenpox during the first five months of pregnancy can lead to severe birth defects. 


What is the link between chickenpox and shingles?

After the initial infection, some inert and dormant pathogens remain in the bodies nerve cells, and may later in life become reactivated, even after years or decades. In adults, this can cause an unpleasant illness- shingles (herpes zoster).


Take home messages… 

  • Chickenpox is a highly infectious disease that affects virtually the entire child population, and most of the adult population. 
  • Most commonly, it is a mild to moderate illness, that becomes more severe with increasing age, or when in association with other comorbidities (another underlying disease).
  • As a viral infection, it is important to treat chickenpox with a resting regime, and some over the counter medication to treat the symptoms (fever medication, antihistamines to reduce itchiness, and skin ointments.) During the recovery period, it is important to get enough vitamins to aid healing, and in the case that some scarring remains after the blisters, it is important to avoid UV, to prevent unwanted skin pigmentation. 
  • Individuals, who by adulthood have not yet had chickenpox, should get tested for antibodies against the varicella virus. In the case of absence of antibodies, these individuals should get vaccinated. 


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