Chickenpox

Chickenpox is primarily recognised by its characteristic rash. However, other signs usually appear one to two days before the rash develops.
Early symptoms often include mild fever, unusual fatigue, headache and sometimes loss of appetite. This is followed by the rash phase, which progresses in several stages:

• First, small red spots appear on the skin, mainly on the face, scalp, chest and back. These spots are called macules.
• They quickly form small, slightly raised bumps called papules. These often cause severe itching.
• Within a few hours, blisters filled with clear fluid, called vesicles, form. It is at this stage that the lesions are most contagious.
• These blisters then burst, forming scabs that fall off within a few days, sometimes leaving lighter areas on the skin.

It is common to see several types of spots on the skin at the same time, at different stages of development. The rash usually starts on the face and scalp, then spreads to the chest, back, arms and legs. The mouth, eyelids and genital area may also be affected.
In children, the symptoms are often mild. However, adolescents and adults may experience a higher fever, a more altered general condition, and sometimes a more extensive rash.

Chickenpox is caused by the varicella-zoster virus (VZV). It is a highly contagious virus, which means that it is very easily transmitted from one person to another. The virus enters the body, multiplies, and then causes the characteristic rash after an incubation period of 10 to 21 days. The virus spreads mainly through droplets of saliva projected into the air when an infected person coughs, sneezes, or talks. It can also be transmitted through direct contact with chickenpox blisters or contaminated objects, such as clothing or toys.
A person with chickenpox can infect others from one or two days before the first blisters appear until all the blisters have formed scabs. This can take about a week

Some people are more at risk of contracting chickenpox or developing a more severe form of the disease. These risk factors relate to both the likelihood of infection and the severity of symptoms.
Factors that increase the risk of catching chickenpox include:

• Not being vaccinated or having had the disease in the past.
• Living in a community setting, such as a nursery, school or care home.
• Close and prolonged contact with an infected person, especially in the same household.

The following people are particularly at risk of developing severe forms of the disease:

• Newborns, especially if their mothers have never had chickenpox or have not been vaccinated.
• Pregnant women, in whom the disease can cause lung complications or affect the foetus.
• Immunocompromised individuals, i.e. those whose natural defences are weakened.
• Adults, for whom chickenpox is generally more severe than in children.
• People with chronic respiratory diseases or who are taking long-term cortisone or salicylate treatments.

The season can also play a role: chickenpox is more common in winter and spring, especially in temperate regions.

Chickenpox is usually recognised upon examination of the skin. The simultaneous presence of red spots, fluid-filled blisters and scabs is often sufficient to make a diagnosis. These lesions develop over a few days and are found on the face, chest, back and limbs.
When the appearance of the spots is unclear or in case of doubt, a laboratory test can be performed. The most reliable test is the PCR test, which is performed on fluid from the lesions. It confirms the presence of the virus, particularly in at-risk individuals or atypical cases.

Chickenpox heals spontaneously within a few days in most healthy children. Treatment aims to relieve symptoms:

• Paracetamol for fever.
• Antihistamines and local treatments to relieve itching.

Topical treatments such as white paint are not recommended. Although they may provide temporary relief, they can mask the signs of a bacterial superinfection and thus delay the detection of a complication.
It is advisable to cut nails short and avoid scratching the lesions to prevent secondary skin infection. Finally, it is also advisable to wash the body once a day with a mild antiseptic soap (such as Septivon) to prevent secondary infections of skin lesions.

In adolescents, adults or frail individuals, antiviral drugs may be prescribed to reduce symptoms and the risk of complications, if given within the first 24 hours after the onset of the rash.

Chickenpox is often mild, but it can lead to complications, especially in adults, pregnant women, infants or people with weakened immune systems:

• Skin infections due to scratching.
• Pneumonia, especially in adults (rare).
• Neurological damage, such as encephalitis (rare).
• Kidney damage in the form of glomerulonephritis, an inflammation that can temporarily impair kidney function.
• Hepatitis, an inflammation of the liver in some severe forms (rare)
• Risks to the baby in case of infection during pregnancy

Later, the virus can reactivate in the form of shingles, a painful localised rash

The chickenpox vaccine is the best protection. It is given in two doses and prevents most severe cases. Even if infection occurs after vaccination, the symptoms are much milder. The vaccine is recommended for children, non-immune adults and people living with vulnerable individuals. After risky contact, rapid vaccination can reduce the severity of the disease.
Note: a specific vaccine against shingles (a disease caused by the reactivation of the chickenpox virus) is recommended from the age of 65, or earlier in the presence of certain risk factors.

In most cases, chickenpox does not require medical attention. However, it is advisable to seek prompt medical attention in the following situations:

• The child has a high fever that persists for more than a few days.
• Signs of skin infection appear around the spots: redness, heat, purulent discharge.
• The child seems drowsy, disoriented or has severe headaches.
• Chickenpox occurs in a pregnant woman, a newborn baby or an immunocompromised person.
• The rash is very extensive or affects the eyes, causing discomfort or pain.

Medical advice can then be sought to adapt the treatment or initiate antiviral therapy.

In most cases, chickenpox can be treated at home without medical intervention. However, Hôpital de La Tour offers tailored support for situations requiring special assessment or monitoring. The paediatrics, internal medicine and infectious diseases teams work together to provide close monitoring, whether in consultation, in the emergency department or during hospitalisation. The hospital also has a 24-hour emergency and paediatric emergency department.

Can adults catch chickenpox?

Yes. If a person has never had chickenpox or been vaccinated, they can catch it at any age. In adults, the disease is often more severe, with a higher risk of complications such as pneumonia.

How long is chickenpox contagious?

A person is contagious 48 hours before the rash appears and until all the lesions have formed scabs, which is usually 7 to 10 days.

Should a child with chickenpox be isolated?

Yes. It is recommended that the child be kept at home until all the lesions are dry. This prevents the virus from spreading to other children or adults who are not immune.

Does the vaccine provide complete protection?

The vaccine does not provide 100% protection, but it is very effective. According to Infovac Switzerland, it reduces the risk of chickenpox by 92% and provides 98% protection against severe or complicated forms of the disease. If a vaccinated person does catch the disease, the symptoms are usually mild and short-lived.

My child has spots: how can I be sure it's chickenpox?

Chickenpox can be recognised by the successive appearance of red spots, blisters and then scabs, often accompanied by fever and itching. If in doubt, a doctor can confirm the diagnosis.

Is shingles related to chickenpox?

Yes. Shingles is a reactivation of the same virus that causes chickenpox. It often occurs years after the initial infection, especially in adults over 50 or people with weakened immune systems.