Children, as well as adults, are infected through contact with the virus through the respiratory tract, although it can also occur through contact with vesicular lesions (small blisters) that occur on the skin of infected people.

Nov 11, 2019

What is chickenpox


Chickenpox is an infectious disease produced by the varicella-zoster virus, one of the known viruses of the herpes virus family, capable of producing in a first infection, the symptoms of chickenpox.


Throughout the patient’s life, on another occasion and due to a decrease in immunity (defenses), the same virus can trigger the appearance of Herpes Zoster, colloquially known as “shingles”, due to the extension of the dermal lesions it produces. This other entity may develop because after the first infection in chickenpox, the virus is cantoned or lodged in sensitive nodes of the nervous system.


Children, as well as adults, are infected through contact with the virus through the respiratory tract, although it can also occur through contact with vesicular lesions (small blisters) that occur on the skin of infected people. Anyone with chickenpox can spread it from the onset of the prodromal stage until all the lesions are crusty. Transmission through the placenta is also described, resulting in congenital chickenpox in the newborn.


The times of the year when epidemics occur are the beginning of spring and autumn, appearing in 90% of cases in infants between 1 and 14 years.


How does chickenpox infection affect children? What are its symptoms?


The symptoms are divided into several phases:

  • Incubation period: lasts about 14 – 16 days.
  • Prodromal period: lasts 1 – 2 days, may go unnoticed or produce in the child irritability, discomfort, fever, headache, or catarrhal symptoms, among others.
  • Exanthematic period: 3 – 5 days. There is intense itching, the appearance of so-called rash or small reddish lesions on the skin that evolve into transparent blisters. The latter subsequently become muddy and break, giving rise to the appearance of crusts. The first lesions usually appear on the face and scalp, gradually extending to the trunk and limbs. The lesions can also affect the mucous membranes (lining of cavities such as the mouth, genitals, etc.), as well as the sclera of the eyes (the white part). The palms of the hands and the soles of the feet are preserved. Normally, three consecutive outbreaks of dermal lesions may appear, leading to the coexistence of lesions at different stages of evolution. In addition, this entire process may be accompanied by fever in the first few days of the onset of the outbreak.
  • Declining period: lasts approximately one week. During this period, the child presents scabs on the lesions that, when falling, leave a light or dark colored lesion that can be sustained for months.


Clinical variations may appear within the presentations of chickenpox, such as congenital or fetal chickenpox syndrome, which affects babies of mothers who suffered from the disease in the first half of pregnancy. This fact leads the child to present cerebral, ocular, genitourinary alterations, growth retardation, etc.


Newborn chickenpox occurs if the baby’s mother gets the infection before 5 days prior to delivery. However, postnatal chickenpox appears if the baby becomes infected after the first 48 hours after birth.




Although chickenpox is usually a benign disease, patients with risk factors such as immunodeficiencies (low defenses), malnutrition, children under 3 months of age are more susceptible to developing more serious complications such as respiratory distress (pneumonia), nervousness (meningitis, meningoencephalitis, cerebellar ataxia, etc.), haematology (post-infectious purpura) or other alterations such as hepatitis, arthritis, Reye’s syndrome, etc.


How is it diagnosed?


The diagnosis of chickenpox is basically clinical, by observation of the symptoms and lesions presented by the child. In severe or atypical forms, a blood test is performed to detect antibodies against the virus (proteins of the immune system that fight the virus). The presence of the virus can also be detected by laboratory analysis of samples of organic material where the virus is present (respiratory secretions, liquid contained in skin vesicles, etc.).


How is it treated?


In most cases where there are no complications and there is no immunodeficiency, measures are taken to improve symptoms: soft diet, avoid itching with antihistamine drugs or other ointments to relieve it, baths with oatmeal soap, disinfection of the lesions with antiseptics, analgesics such as paracetamol to control discomfort and fever (avoiding acetyl salicylic acid as it can trigger Reye’s syndrome). In addition, if dermal lesions are overinfected by bacteria, antibiotics may need to be used.


The pediatrician will indicate to the caregivers the rest of the child at home being able to return to school or nursery school when the scabs have fallen, the child is without fever and in good condition overall.


Children under 3 months of age are usually admitted to hospital to monitor their condition. Patients with risk factors, affected defenses, neonatal varicella or complications such as meningitis, pneumonia, etc., antiviral drugs (Acyclovir) are used on, administered if possible in the first 24 hours after the onset of skin lesions with hospital control, administered intravenously or orally depending on the child’s state of health and age.


Can it be prevented?


The most effective prevention measure is vaccination. It is a vaccine of attenuated varicella-zoster virus (containing the whole virus, but with less virulence) that is administered by subcutaneous injection in children older than 12 months. Specifically, two doses are recommended in children: the first between 12 and 15 months and a second administration between 4 and 6 years.

In some cases, post-exposure prevention or prophylaxis is required, which can be carried out with vaccination, if administered within 3 days of exposure, or depending on the pathologies and situation of the patient (premature babies, immunosuppressed, newborns whose mothers have suffered from the disease within 5 days prior to birth, etc.), they are administered anti-varicella-zoster gamma globulins (antibodies, i.e. proteins of the defense system) in the first 72 hours after exposure.


Another fundamental prevention measure is the isolation of people suffering from the disease, avoiding direct contact with respiratory secretions and dermal lesions, as well as the general hygiene of patients and their caregivers.