Chickenpox is the most contagious of all childhood diseases, with epidemic peaks in winter and spring, and although generally uncomplicated, it is not so benign, as it is responsible in France for more than 3,000 hospitalizations per year and around 20 deaths.
It is of viral origin caused by the varicella-zoster virus or VZV - belonging to the group of herpes viruses. It affects children (about 95% of cases) more often than adults (5% of cases) - adults who did not get it in childhood - and in this case it is more serious: pulmonary complications and encephalitis. It is a disease with definitive immunity, as it cannot be contracted twice, but the virus remains latent in the nodes of the posterior sensory spinal nerve roots, and can reactivate later as shingles.
There is a vaccine, but it is not widely used in France, and is mainly prescribed to fragile children (with a chronic and/or severe disease that can lead to a severe form of chickenpox in children).
Transmission from one person to another can occur through different routes:
- contact with the pimples, which are highly contagious at the blister stage (they are no longer contagious when they are crusty),
- Respiratory secretions (droplets of saliva: when talking, especially when coughing or sneezing),
- indirect contamination by contaminated objects or clothing.
A person infected with the virus is contagious between two/three days before the onset of symptoms and up to seven days after the blisters appear.
Symptoms
Chickenpox has an incubation period of about 15 days.
The first signs are a fever of about 38° and redness of the skin, then the rash arrives (these are the papules), and there will be several successive outbreaks (two or three) separated by one to three days. There will be coexistence on the skin of pimples of different ages: macules, papules, vesicles and scabs.
The patient may also have headaches, sore throat, cough and often tearing. Papules are small red superficial vesicles 2 to 4 mm in diameter, which usually appear first on the chest and will spread over the whole body (scalp, thighs, arms, mucous membranes, armpits...), and will eventually reach the face. These papules are filled with a clear, highly contagious liquid ("dewdrop on healthy skin"), which will become cloudy in two days, dry out, and give way to scabs that will eventually fall off in 5/6 days. Scars will remain and will fade after several weeks.
Caution: the itching is important and can lead to over-infections.
Shingles, which is a resurgence of the disease, starts with a burning sensation in the affected nerve, and sometimes with a moderate fever. Between one and three days after the burning sensation starts, a blister-like rash similar to chickenpox occurs. This rash will only appear in the area of an affected sensory nerve and is often characterized by its clustering. Two or three days after the appearance, the vesicle dries out, and there will be a crust that will remain for a dozen days before falling off. The skin will then be depigmented and slightly depressed. The disease causes sensations of pain/burns that will quickly disappear, however, in some cases, these residual pains may last a few weeks or even months and very rarely remain persistent (three cases in my professional life).
Complications
The most frequent is skin superinfection in children due to scratching lesions (hence the need to soothe this itching). The two bacteria most often involved are staphylococcus and streptococcus. These superinfections can evolve, in the most severe cases, into septicaemia which can be fatal.
Neurological disorders follow. The virus can cause encephalitis (inflammation of the brain) or cerebellitis (inflammation of the cerebellum). Symptoms include ataxia (difficulty coordinating movements), nystagmus (uncontrollable eye movements), headaches, nausea, and vomiting. Healing will occur in two to four weeks. These complications, which can very rarely leave after-effects, are exceptionally fatal.
In third place, in order of frequency, come the pulmonary complications: pneumonia or pleurisy related to a bacterial superinfection by the streptococcus, or pneumonia caused directly by the virus. In adults, with the invasion of the lung by the varicella virus, the most serious complications are the occurrence of encephalitis and interstitial pneumonia. In immunosuppressed patients, these complications can be very serious, sometimes fatal. Properly treated, recovery will take a few weeks, with no major after-effects.
Other possible complications include Reye's syndrome.
In pregnant women and during the first months of pregnancy, chickenpox can cause embryonic abnormalities.
In the fetus, a few days before delivery, or the baby a few weeks after delivery, chickenpox is very serious with the risk of a severe infection but also pneumonia, meningoencephalitis or hepatitis.
Diagnosis
It is based on clinical examination and is based on the identification of typical chickenpox vesicles on the skin. Direct detection of the virus by biological diagnosis is only useful for severe forms, immunosuppressed people and pregnant women.
Not to be confused with ... (non-exhaustive list):
- Scabies vesicles,
- insect bites,
- bubbly impetigo,
- widespread herpes infection,
- Eczema blisters...
Treatment
The basic treatment consists of relieving itching and avoiding complications (superinfections).
- anti-histamines (against itching) are used, which will be prescribed by the doctor, and local application with calamine fluid gel (after the use of antiseptics) will be advised, do not use talcum powder, which promotes maceration and superinfection
- Hygiene measures will be taken daily: antiseptic cleaning of pimples and cleaning of nails, which will have been cut short (superinfection through scraping), especially as scraped pimples can cause indelible scars.
- antipyretics are useful to fight fever (not aspirin or ibuprofen, which are contraindicated with chickenpox).
Superinfections may require antibiotic treatment to limit their spread through the skin (impetigo) or even generally (septicaemia).
The prescription of antivirals as well as specific immunoglobulins is only used in certain serious cases.
Treatment of shingles: treatment is symptomatic like chickenpox. In case of pain, painkillers and certain benzodiazepines (clonazepam) are prescribed.
Prevention of chickenpox
Until complete healing (scabs fall off), the child should not attend day care or school and should be isolated.
Immunocompromised individuals who have not had chickenpox should avoid contact with the sick.
There is a vaccine, consisting of a live attenuated virus, which is prescribed to immunocompromised children and their families: VARILRIX by GlaxoSmithKline and VARIVAX by Sanofi Pasteur MSD (CAUTION: Before vaccinating women of childbearing age, make sure that you are not pregnant and that you are taking contraception up to 3 months after vaccination (see Contraindications and Pregnancy). Varivax - and Varilrix - is generally not recommended in breastfeeding mothers (see Breastfeeding).
Advice
Avoid baths and contact with water at the beginning of the eruption as this slows down the drying of the crusts and increases the risk of superinfection.
Evolution of the disease:
The prognosis is usually good, chickenpox heals spontaneously in 10 to 15 days. The disease leaves no after-effects, except for scars on the skin when the pimples have been scratched or superinfected.