chickenpox

Generality

Chickenpox is a highly contagious disease that affects children and young adolescents electively, but not only.

It is caused by the primary infection of the varicella-zoster virus . After recovery, the same virus can cause - even after many years - shingles or shingles.

Chickenpox has a natural benign course and, in almost all cases, tends to spontaneous healing even if left untreated.

The risk of complications becomes particularly concrete when the immune defenses are low, as in children treated with cortisone, chemotherapy or immunosuppressants, and in people with HIV infection.

Insights

Symptoms and PhotosComplications Contagion Treatment and treatment Medicines for the treatment of varicellaVaccination

Symptoms

To learn more: Symptoms of varicella

Chickenpox is manifested through the appearance of numerous red spots - first flat, then in relief - which rapidly evolve into vesicles (bubbles with a diameter of a few millimeters, filled with clear liquid which becomes cloudy within a few days).

Photo Chickenpox

Figure: typical appearance of varicella vesicles. See More Chickenpox Photos

These vesicles are distributed a little on the whole body, in particular in the face, in the scalp, in the thorax and in the back; sometimes even inside the eyes, the oral mucosa and the vagina.

Incubation period and prodromal phase

The classic varicella rash is preceded by an incubation period of 13-17 days and a prodromal phase that lasts approximately 48 hours.

The short period before the appearance of the exanthema (called precisely the prodromal phase) is characterized by fever, loss of appetite, slight cough and general malaise.

Exanthematic phase

1. Initially there are small flat red spots, red and 2-3mm large, like a lentil (doctors talk about Macule );
2. Within a few hours, the macules evolve into papules, that is, they become raised with respect to the skin;
3. Within a few hours, the papules fill with liquid (the doctors talk about blisters );

Indicatively, the evolution from macules to vesicles lasts from 6 to 8 hours.

• As soon as they appeared, the vesicles were light in color and their contents were clear
• During the following 24 hours the liquid becomes cloudy and the vesicles take on an opalescent or milky appearance.

The varicella skin lesions do not all appear together, but arise in small waves, spaced a few days apart; for this reason eruptive processes coexist in the body of the patient in different stages of evolution, accompanied by a more or less intense and annoying itching. To describe this phenomenon, doctors talk about starry skies . In addition, some papules can undergo early healing, without passing through the vesicle phase.

If chickenpox complicates into bacterial superinfection of the skin, the vesicles turn into pustules, acquiring the classic yellow cap for the presence of purulent material.

Remission Phase

After a few days from their appearance, the vesicles evolve into scabs; so we enter the last stage of chickenpox, which leads the patient to complete recovery: drying and falling crusts.

In this phase, the vesicle is covered with a dark crust that, after 7-20 days, comes off spontaneously without leaving any scarring. On the contrary, when the patient torments vesicles or crusts favoring their premature rupture, chickenpox can result in small permanent scars .

The risk of scar formation is even greater in case of vesicle infection.

In the typical form, after the appearance of the first papules, it takes from seven to fourteen days for the skin to completely resolve.

The spots following the fall of the crusts last about 20 days but are not contagious.

Contagion

Chickenpox is a rather contagious disease, affecting at least 90% of susceptible or seronegative individuals.

The contagion is only inter-human, which means that chickenpox is transmitted only from human to human and not from animal to human.

The greatest number of infections is recorded in late winter and early spring, probably due to close contact in schools.

In the boot, an estimated 500, 000 cases of chicken pox a year.

Period of contagiousness

• The subject begins to be contagious 2 or 3 days before the appearance of the rash.
• Infectivity is maximum in the 24-48 hours preceding the appearance of the first vesicles and in the following 5-6 days.
• The infectiousness lasts until all the lesions have turned into scabs.
• In the immunocompromised the infectivity period is instead wider.

Transmission Mode

The varicella zoster virus is transmitted:

1. through direct contact with the rash (touching the vesicles);
2. by air, through the droplets of saliva dispersed by the patient during conversation or through coughing and sneezing.

In case of breakage, the liquid contained in the vesicles can transmit the infection also by air diffusion; the virus is still labile and, therefore, it is not transmitted with contaminated objects.

During pregnancy, chickenpox can be transmitted to the embryo or fetus through the placenta. See details: chickenpox in pregnancy.

Prevention and Isolation

The spread of chicken pox can be prevented by isolating affected individuals.

According to what has been said so far, the disease spreads rapidly in overcrowded places, such as care facilities, prisons and schools. This explains the recommendation to isolate the patient, especially avoiding contact with those most at risk (pregnant women and newborns).

Even more severe are the regulations adopted in hospitals, where the sick person suffering from chickenpox must be isolated, especially from the immunosuppressed.

Likewise, susceptible health personnel should be vaccinated, in order not to be a source of infection.

Vaccinated people, as well as those who have already suffered it in the past, are immune to chicken pox and any danger of infection; it is indeed extremely rare, even if possible, for a person to develop this disease twice. Currently, in Italy, the varicella vaccine is optional.

What changes since 2017

With the decree law on the prevention of vaccination for minors from zero to 16 years, approved on 07/28/2017 , vaccination against chickenpox has become mandatory .

This specific vaccination can be performed with a single injection together with 3 other vaccination covers (the so-called quadrivalent MPRV vaccination, which includes vaccines: anti-measles, anti-rubella, anti-mumps, anti-varicella).

• The vaccination requirement against varicella is in force, in the context of the 10 mandatory vaccinations, only for those born in 2017.

Please note that compulsory vaccinations are a requirement for admission to nursery schools and kindergartens (for children from 0 to 6 years) and that the violation of the vaccination requirement implies the application of significant financial penalties .

For more information on mandatory vaccines in children, see this article.

Isolation of Children

As for the isolation of children, we must not forget that chickenpox is infectious even before the rash occurs (it begins to be 2-5 days in advance); moreover, it is much better to contract it in childhood, when it almost always has a benign course, rather than during adolescence or adulthood, where complications are more common.

Therefore, in the presence of childhood varicella, not all doctors agree in suggesting abstention from lessons outside the period strictly necessary to recover energy.

Complications

In the immunocompetent patient, chickenpox is a benign disease, which resolves spontaneously within 7-10 days. This is especially true in childhood, while complications are more common in adults, newborns and adolescents.

Rare in healthy individuals, more common among immunosuppressed or in the presence of thrombocytopenia, haemorrhagic varicella is a rather aggressive form, characterized by bleeding vesicles and, sometimes, aggravation of general conditions (high fever, involvement of the viscera).

In these cases, especially when the patient is particularly weak, chickenpox can seriously endanger the survival of the individual.