Chickenpox (varicella) in children

Chickenpox (varicella) is an acute viral infection that causes moderate fever and the appearance of small blisters with clear contents on the skin and mucous membranes.

Chickenpox is a typical childhood infection. Almost the entire population of the Earth suffers from chickenpox before the age of 10-14.

Epidemiology

The only source of chickenpox is a sick person. The patient is contagious for a day before the first rash appears and for 3-4 days after the last blisters appear, especially at the beginning of the rash. The source of infection can also be patients with herpes zoster. The causative agent of chickenpox is present in the contents of the blisters, but is not found in the crusts.

Chickenpox is transmitted by airborne droplets, less often by contact, and infection is possible over a long distance. The virus easily spreads with the air flow through the ventilation system, stairwells from floor to floor. Transplacental transmission of the virus from mother to fetus has been proven.

Children in the first 2-3 months of life rarely get chickenpox. However, if the mother has no immunity, newborns can also get sick. After the infection, strong immunity remains. Repeated diseases are rare, no more than 3% of cases.

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Causes chicken pox in a child

The causative agent of chickenpox (varicella) is the herpes virus type 3, which contains DNA; its properties are similar to those of the herpes simplex virus and are indistinguishable from those of the herpes zoster virus, which is why it is designated as the varicella-zoster virus.

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Pathogenesis

The entry point for infection is the mucous membrane of the upper respiratory tract. This is where the primary reproduction of the virus begins. It enters the bloodstream via the lymphatic system. The virus is carried by the bloodstream into the epithelial cells of the skin and mucous membranes and is fixed there. Bubbles are formed, filled with serous contents, which contain a high concentration of the virus. In addition, the chickenpox virus has a tropism for nervous tissue, and can affect the intervertebral ganglia, the cerebral cortex, the subcortical region, and especially the cerebellar cortex. In very rare cases, visceral organs may be affected, primarily the liver, lungs, and gastrointestinal tract.

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Symptoms chicken pox in a child

The incubation period of chickenpox is 11-21 days, on average 14 days. Chickenpox begins with an increase in body temperature to 37.5-38.5 °C and the appearance of a chickenpox rash.

The primary element of the rash is a small papule spot, which quickly, after a few hours, turns into a vesicle with a diameter of 0.2-0.5 cm. Chickenpox vesicles are round or oval, located superficially, on a non-infiltrated base, surrounded by a rim of hyperemia, their wall is tense, the contents are transparent. Individual vesicular elements have an umbilical depression in the center. The blisters are usually single-chambered and fall off when punctured. At the end of the first, less often on the second day from the onset of the rash, the blisters dry up and turn into a brown crust, falling off in 1-3 weeks of the disease. After the separation of the crusts, gradually "fading" pigment spots can be seen for a long time (up to 2-3 months), but scars do not form. The rash is located on the face, scalp, trunk and limbs. There is usually no rash on the palms of the hands or soles of the feet.

Vesicular rashes often appear on the mucous membranes of the oral cavity, conjunctiva, and less often on the mucous membranes of the larynx and genitals. The elements of the rash on the mucous membranes are tender, quickly open up and turn into superficial erosions, and slight pain may occur. Healing of erosions occurs on the 3rd-5th day after the rash appears.

With chickenpox, the rash does not appear simultaneously, but rather in fits and starts, with intervals of 1-2 days. As a result, elements at different stages of development can be seen on the skin - maculopapules, vesicles, crusts. This is the so-called "false polymorphism" of the rash, characteristic of chickenpox. Each new rash is accompanied by a new rise in body temperature, so the temperature curve for chickenpox has an irregular shape. Peripheral blood is practically unchanged with chickenpox. Sometimes slight leukopenia and relative lymphocytosis are observed.

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Forms

A distinction is made between typical and atypical chickenpox.

Typical cases include cases with characteristic vesicular rashes filled with transparent contents.

Typical chickenpox is divided according to severity into mild, moderate and severe.

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Complications and consequences

With chickenpox, complications are specific, caused by the direct action of the virus, and can arise as a result of a bacterial infection.

Among the specific complications, the most important are chickenpox encephalitis and meningoencephalitis; less common are myelitis, nephritis, myocarditis, etc.

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Diagnostics chicken pox in a child

The diagnosis of chickenpox is established on the basis of a typical vesicular rash all over the body, including the scalp. The rash undergoes a peculiar evolution and is distinguished by polymorphism.

Laboratory methods include PCR to detect viral DNA in vesicular fluid and blood. Complement fixation and ELISA are used for serological diagnostics. Worthy of attention is the immunofluorescence method, which can detect chickenpox antigen in smears-prints from the contents of vesicles.

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Treatment chicken pox in a child

It is necessary to strictly monitor the child's hygiene, cleanliness of bed linen, clothes, and hands. Vesicles are lubricated with a 1% solution of brilliant green or 1-2% solution of potassium permanganate. General baths with a weak solution of potassium permanganate, rinsing the mouth with disinfectant solutions after meals are recommended. It is advisable to treat vesicles with 5% cycloferon liniment. If purulent complications occur, antibiotics are prescribed. Glucocorticoid drugs are contraindicated in chickenpox, but if chickenpox encephalitis or meningoencephalitis occurs, they have a positive effect. In severe forms, an antiviral drug from the acyclovir group is prescribed at a rate of 15 mg / kg per day orally or intravenously, as well as an injection solution of cycloferon at a rate of 10 mg / kg. Such therapy interrupts the course of chickenpox.

Treatment of chickenpox (varicella) with antiviral drugs is quite effective even in the development of chickenpox complications (encephalitis, pneumonia, etc.). There are also reports of the antiviral action of children's anaferon, the inclusion of which in standard therapy for chickenpox has significantly reduced the duration of the main clinical symptoms and reduced the number of bacterial complications.

Prevention

Patients with chickenpox and herpes zoster are isolated at home for up to 5 days from the moment of the last rash. Only children with severe or complicated forms of the disease are subject to hospitalization; they are necessarily placed in a Meltzer box. In case of meningoencephalitis, hospitalization is mandatory. Children of nursery age (up to 3 years old) who have been in contact with patients with chickenpox and herpes zoster and have not been ill before are isolated from the 11th to the 21st day from the moment of contact. Final disinfection in the infection site after isolation is not carried out due to the instability of the virus. It is enough to ventilate the room after isolating the patient and do a wet cleaning. The chickenpox vaccine is also used.

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