VARICELLA: symptoms, contagion and incubation of chickenpox in children, adults and pregnancy

Lto chickenpox is a disease caused by virus Varicella zoster which belongs to the family of Herpesvirus. In English it is defined chickenpox, and it is a common and highly pathology contagious and can affect all susceptible individuals, the peak incidence occurs in pediatric age, more than 90% of cases in fact affects infants and children under 10 years of age. 

Chickenpox

What is chickenpox?

There chickenpox is a disease caused by virus Varicella zoster which belongs to the family of Herpesvirus. It is a common and highly pathology contagious and it can affect all susceptible individuals, adults and children, even if the peak of incidence occurs in pediatric age: more than 90% of cases in fact affects children under 10 years of age. Generally it determines a clinical picture that is not severe and self-limiting but sometimes it can evolve with complications even severe.

Contagion and incubation of chickenpox

How does the infection of the chickenpox? The infection comes transmitted through droplets of saliva or secretions airways produced by an infected person. High concentrations of viruses are also present in the liquid contained in skin blisters chickenpox: transmission, although less frequently, can therefore also occur through the direct contact with these vesicles.

2 to 4 days after the transmission of the infection the virus replicates in the lymph nodes of the high respiratory tract and this is followed by a first diffusion in the blood - viraemia  - through which the virus reaches the internal organs, mainly the liver and the spleen.

What is the duration of the period of incubation? The period of hard incubation from 10 to 21 days, then a second viremia occurs through which the virus reaches the skin with the subsequent appearance of the typical ones vesicles. The patient is contagious for 1-2 days before the rash appears and remains contagious until all the blisters have evolved into scabs. 

However, the indirect contagionIn other words, it is not normally possible for a person to transmit chickenpox without contracting it themselves. So, if a child comes into contact with another infected child at school, it will only be contagious if he gets the infection and develops chicken pox.

Chickenpox Symptoms

What are the main symptoms of chickenpox? THE first symptoms of chickenpox I'm:

  • temperature preceding the rash
  • rash
  • itch intense

The typical rash is characterized by successive waves of papules which appear starting from head is trunk and they spread to the rest of the body and which they first evolve into vesicles, then in pustules and then into injuries crusty. The scars they will progressively resolve over a few days.

Chickenpox spots and lesions on the skin

Red spots, scabs and blisters, the typical skin lesions of chickenpox

Many people mistakenly speak of "bubbles " of the chickenpox: actually the blisters indicate very large vesicles, over 10 mm, while in chickenpox the lesions are very small, only a few millimeters in size.

In some cases, the rash may also appear without fever: it is therefore evident that the absence of fever does not exclude the presence of a Varicella Zoster Virus infection.

In some cases, symptoms such as abdominal pain, headache o headache -, cough, sore throat.

How quickly does the healing? There duration chickenpox usually occurs over a period of time between 5 and 10 days. The vesicles can also appear in the mucous membranes (eg oral cavity), causing very painful lesions. The disease can have a trend more aggressive in the adolescent e in the adult.

Chickenpox

Erythema with red spots and blisters on the body in chickenpox

 

Complications of chickenpox

In many cases, chickenpox occurs in light shape and symptoms are limited to fever and skin involvement. Complications of chickenpox are often present in adolescents and children adults, as well as in newborns. Moreover, often too children with defects of the immune system they can have severe forms (disseminated chickenpox) and complicated forms of chickenpox. Complications of chickenpox can be:

  • bacterial over-infection of skin lesions (impetigo, erysipelas, cellulite),
  • thrombocytopenia,
  • hepatitis,
  • arthritis,
  • pneumonia,
  • glomerulonephritis,
  • neurological involvement (encephalitis, cerebellitis, Guillain Barrè syndrome).

After infection, antibodies cause aimmunity that persists for lifetime. After infection, the viruses localize in the roots of the sensory nerves, i nerve ganglia. Its reactivation determines the clinical manifestations of Herpes Zoster (so-called fire of Sant 'Antonio).

Chickenpox in pregnancy

If the chickenpox is contracted at the beginning of pregnancy there is a risk (1-2%) for the fetus to develop the so-called syndrome of the congenital chickenpox which is characterized by muscle atrophy, skin scarring, microcephaly, cataract, chorio-retinitis, microphthalmia, developmental delay.

Babies who have been exposed to the chickenpox virus in utero after the twentieth week of gestation may develop a asymptomatic chickenpox and subsequently shingles in the first years of life. If the mother develops chickenpox in the days close to giving birth - 5 days before to two days before delivery -, the baby may develop a disseminated chickenpox which features a mortality of 30%.

Chickenpox Diagnosis

There diagnosis of the chickenpox is based on the clinical picture. Blood tests show a reduction in white blood cells - leukopenia - in the first 3 days, followed by a slight increase in them – leukocytosis. The finding of high white blood cells can also indicate the presence of bacterial over-infection.

In some cases a increased liver enzymes, indicative of hepatitis. Virus isolation by means of a culture of the liquid contained in vesicles it allows to have a definitive and certain diagnosis, but the culture techniques are complicated and are positive in less than half of the cases.

In some laboratories, PCR is available on biological material (polymerase chain reaction), which is very sensitive but expensive. The search for antibodies for the virus of the Chickenpox it allows to evaluate the previous exposure to the virus and to ascertain the susceptibility of the subject to infection.

There chest x-ray it is indicated if pneumonia is suspected.

Treatment of chickenpox

How to care chickenpox? V.Given the generally benign and self-limiting course of the infection, the therapy it is only symptomatic. In case of severe itching, baths with products can be performed soothing of itching (e.g. based on oats) or use drugs antihistamines. The remedy for fever can be paracetamol, while, at least in children, the use of salicylates (such as acetylsalicylic acid contained in aspirin) should be avoided due to the high risk of developing syndrome of Reye.

The administration of antiviral drugs, such as acyclovir, in healthy children, within 24 hours of symptom onset, has been shown to lead to a reduction in the symptoms and duration of chickenpox, but is not currently recommended. There oral antiviral therapy it is indicated instead in cases with a higher risk of severe forms of chickenpox (eg adolescents or adults).

Debilitated or immunocompromised people must be treated more aggressively due to the risk of disseminated forms or complications, with drugs administered intravenously. To avoid the spread of the disease is recommended isolation of patients, especially children have to stay home from school for at least 5-6 days after the appearance of the first vesicles or in any case until all the vesicles have evolved into crusts.

Chickenpox vaccine

For the prevention chickenpox is available a vaccine, consisting of a live attenuated virus. The vaccine is safe and well tolerated, provides long-lasting protection and prevents severe to moderate forms in 95% of cases. A small percentage of people will still be able to contract the infection after vaccination for the chickenpox, but in this case the manifestations are mild with the appearance of few vesicles and a faster resolution.

In Italy the vaccination schedule provides for the administration of two doses of the vaccine:

  1. a first dose between 12 and 15 months,
  2. the second dose at 5-6 years of age.

Individuals over 12 who have never been vaccinated should receive 2 doses of the vaccine at least 28 days apart.

Vaccine for chickenpox: indications and contraindications

There are contraindications to the vaccine? The vaccine being made up of a live attenuated virus is contraindicated in immunocompromised individuals. Vaccination is indicated instead for the women in fertile age who have never had the disease, to avoid a possible infection during pregnancy and the consequent damage to the child (before vaccination, an ongoing pregnancy must be excluded, contraceptives must be used for 3 months after the vaccine).

Side effects of the chickenpox vaccine

That effects collateral can give the vaccine? Mild localized reactions such as swelling, pain, redness at the injection site and also fever (7-10 days after vaccination), mild rash may occur after the vaccine, up to one month after vaccination (1 in 25 people).

More serious reactions are represented by seizures secondary to fever, pneumonia and allergic reactions, complications however much rarer than the complications that chickenpox gives once the infection is contracted.

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