Content

Introduction

Chickenpox is a benign infectious disease caused by the virus chickenpox zoster (VZV). It is included together with rubella, measles, whooping cough and mumps, in the group of infectious childhood diseases; the most affected, in fact, are children between 5 and 10 years of age.

It is characterized by the appearance of a skin rash or rash, which develops in 3 successive stages (pink blisters, blisters / pustules, scabs), by low fever and by mild general disturbances (symptoms) such as feeling unwell and headache. It is very easily transmitted by air through the droplets emitted into the air by the sick person when he coughs or sneezes; or, through direct contact with the liquids released by the rash or with contaminated surfaces and objects.

The disease usually resolves in 7-10 days but can have a more aggressive course in adolescents and adults, especially if the body's defense system (immune system) is weakened. If contracted in early pregnancy it can cause fetal problems.

Infection with the virus Varicella zoster it confers permanent immunity and it is very rare for a person to develop the disease twice. However, the virus, like other viruses belonging to the herpes family, tends to remain in spinal nerve cells even after the disease has resolved. After many years, usually after the age of 50, and in a small percentage of individuals (10-20%) the virus can awaken giving rise to "herpes zoster, a disease commonly known as fire of saint Anthony.

Generally, the treatment of chickenpox is aimed at relieving the ailments (symptomatic treatment).

Since 1995, a live attenuated virus vaccine has been available.

Symptoms

Chickenpox occurs 10-21 days after "contact" (exposure) with the virus and generally resolves within 7-10 days. One or two days before the onset of the rash, some ailments may occur such as moderate fever, loss of appetite, headache, fatigue and a feeling of general malaise.

The rash is the main and most indicative signal for the assessment (diagnosis) of the disease. In the first 3-4 days it occurs in the form of small pink bubbles (papules), very itchy, which appear on the head, trunk, face and limbs (stage 1). They later turn into small, fluid-filled blisters (stage 2), then fill with pus (pustules), and eventually become granular crusts (stage 3) that take several days to heal and are bound to fall off.

Usually, the lesions that appear on the skin (rash) are numerous (250-500), develop in successive waves and can remain for several days. Due to their trend it is possible to observe all 3 stages simultaneously starting from the second day.

Chickenpox is generally a mild disease in healthy children but in some more severe cases, the rash can extend to cover the entire body surface and also manifest itself in the throat, eyes and mucous membranes (urethra, anus and vagina).

Causes

Chickenpox is caused by infection with the virus chickenpox zoster and its transmission can only take place from man to man and not through animals. The transmission of the virus can occur from 48 hours before the appearance of the exanthema up to the complete fall of the scabs.

Getting chickenpox, if you haven't had it or aren't vaccinated, is very easy.Contagion can occur by direct contact with the droplets dispersed in the air by sick people through sneezing or coughing.

The virus belongs to the large family of herpes virus many of which share the characteristic of remaining in the organism even after healing from the disease and can awaken, after many years or decades, giving rise to the "shingles, a disease more commonly known as fire of saint Anthony.

The awakening of the virus from the spinal nerve cells in which it remains hidden, manifests itself with the appearance of cluster vesicles, usually on the trunk, sometimes accompanied by pain that can persist for over a month (post-herpetic neuralgia).

During pregnancy, the virus can be transmitted to the embryo or fetus through the placenta with different consequences depending on the gestation period (see Complications).

Diagnosis and Therapy

The assessment (diagnosis) of chickenpox is based on the appearance of the skin rash and does not require blood tests. In healthy children, chickenpox does not require special pharmacological treatments and the therapy is aimed at reducing the present ailments (symptomatic treatment). It may be necessary to use antihistamines to relieve itching and prevent the child from scratching, slowing the healing of the exanthema and promoting bacterial superinfection. In case of high fever, on the advice of the attending physician, paracetamol can be used.

Children with chickenpox do not need to be treated with i salicylates (aspirin) because it could increase the risk of developing Reye's syndrome, a childhood disease that, although rarely, can occur in children with a viral infection (for example flu, chicken pox) and can cause significant damage to the liver and to the brain.

In people who have a high risk of experiencing complications, acyclovir, an antiviral drug, can be used.This category includes adolescents, individuals with chronic respiratory diseases, people with a weakened body's defense system (immunosuppressed) or being treated with particular drugs (steroids) and in case of subsequent infection of family members (secondary infection) . Antiviral drug therapy is not recommended in healthy children with chickenpox either because the disease usually heals on its own, or because administering the drug by mouth within 24 hours of the onset of the rash results in only a modest reduction in chicken pox. ailments (symptoms).

In people with a weakened body's defense system (immunosuppressed), on the other hand, antiviral therapy in a vein (intravenously) is recommended.

Prevention

The best method for preventing chickenpox is the live attenuated virus vaccine, which has been available since 1995. The effectiveness of the vaccine in avoiding infection has been estimated to reach 95-98% at recommended doses. moreover, it turns out to be long lasting.

Vaccination is recommended for children aged between 12 months and 12 years and is recommended for children over the age of 12 and adolescents who have not yet contracted the disease and have no contraindications to vaccination (read the Bufala). For children born after 2017, vaccination for chickenpox is mandatory in Italy.

The vaccine is also recommended for people who, for professional reasons, have a greater risk of acquiring the infection (such as school staff) or of transmitting it to people at high risk of serious complications (such as healthcare professionals).

Vaccination is also recommended for women of childbearing age who have not yet had chickenpox, to prevent them from becoming infected during pregnancy and damage to the fetus or newborn.

The vaccine is not recommended for people with a weakened body defense system (immunosuppressed) and in pregnant women.

The appearance of the disease in high-risk people (immunosuppressed, newborns, pregnant women) who have been exposed to the virus can be prevented by means of the so-called passive immunoprophylaxis, namely the administration, through an intramuscular injection, of antibodies (immunoglobulins) against the virus chickenpox zoster that provide the body with defenses to avoid infection. Immunoglobulins must be administered as soon as possible and, in any case, no later than 96 hours after exposure to the virus.

The protection afforded by immunoglobulins lasts long enough for the body to make its own antibodies to the virus. However, administration of aciclovir by mouth is not recommended for preventive purposes.

In general, it is advisable to isolate sick people (from school, work, health facilities) to avoid the spread of the infection.

Complications

Chickenpox, in general, is a disease with a benign evolution but some complications can occur in pregnant women, newborns under 4 weeks from birth, people with a compromised defense system of the organism (immunosuppressed), for example , HIV infection, high-dose steroid treatment or chemotherapy.

The most common complication of chickenpox is bacterial superinfection that occurs on the skin when the sick person scratches himself. When this occurs, the skin becomes red, swollen, thin and sore, and it is necessary to contact the doctor to assess the need for treatment with antibiotics.

More rarely, the virus can spread to the lungs causing pneumonia. This is a more common complication in adults, especially if they are smokers. It manifests itself as cough, difficulty in breathing and chest pain, sweating and chills.If such complaints occur, it is important to contact your doctor right away as, in some cases, hospitalization may be required.

In very rare cases, the chickenpox virus can cause severe infections of the brain and nerve cells of the spinal cord in children, pregnant women, immunosuppressed people. The main complaints (symptoms) are: fatigue, drowsiness, confusion, convulsions, vomiting, headache, neck stiffness, balance problems. This complication is usually treated in the hospital.

Chickenpox can be a serious problem if it occurs during pregnancy but a lot depends on the gestation period in which the infection occurs. If contracted during the first 2 months of gestation, chickenpox can lead to embryopathy (congenital varicella syndrome); if the infection occurs after the twentieth week, chickenpox can develop without disturbances (asymptomatic) and, subsequently, in the first years of life, herpes zoster may appear. In cases where the mother becomes ill with chickenpox immediately before or immediately after delivery, the newborn could develop a severe form of chickenpox, the mortality of which can be up to 30%.

Bibliography

Levin MJ, Weinberg A, Schmid DS. Herpes Simplex Virus and Varicella-Zoster Virus [Summary]. Microbiology Spectrum. 2016; 4

Galetta KM, Gilden D. Zeroing in on zoster: A tale of many disorders produced by one virus. Journal of Neurological Sciences. 2015; 358(1-2): 38-45

In-depth link

NHS Choices. Chikenpox (English)

Mayo Clinic. Chikenpox (English)

EpiCentro (ISS). Chickenpox

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