Chickenpox (chicken pox) is a highly contagious infectious disease caused by a virus called chickenpox.
This virus remains in our body all our life, as if asleep; its reactivation determines disease located in the area corresponding to one or more sensory nerves and is called Herpes-Zoster, also known as shingles.
In the pre-vaccine era, 90% of susceptible people developed primary chickenpox or chickenpox disease. In contact between people living in the same house, contamination of the disease occurs in more than 80% of those prone; in less intimate contact (college), drops to 30% of children.
The transmission period begins 24 to 48 hours before the appearance of skin lesions and extends until all vesicles have developed crusts (bark), usually 7 to 9 days. The time between contact and onset of the disease (incubation) is 14 to 16 days, ranging from 10 to 21 days. Transmission occurs through air contact, airway to airway, or direct contact with vesicular lesions whose fluid is full of viruses.
Once lodged in the body, viruses begin to reproduce, invade the blood and produce the signs of infection: fever 38 to 38.5 ° C, malaise, loss of appetite, headache. Symptoms are more or less intense depending on the amount of contaminating viruses and the defense ability of that individual.
Viruses in the respiratory tree are carried to the skin and mucous membranes by the bloodstream. A local inflammatory reaction begins; small, itchy reddish balls appear that quickly evolve into small bubbles with crystalline liquid, which eventually becomes cloudy.
The bubbles retract in the center and dark crust (shell) formation begins. Everything happens in about 2-3 days. Lesions appear in independent "waves", which causes lesions of different evolutionary stages in the same individual, which is one of the most important for confirming the diagnosis. The number of lesions is extremely variable (10 to 1500 in normal people); on average we can talk about 300.
Diagnosis and Treatment
The diagnosis is fundamentally clinical. Treatment is directed at slowing down symptoms. It is a benign disease and the cure is done by the body's own reaction. Today, the most important complications happen through contamination with bacteria. Pregnant women, newborns and individuals with low defenses are cases that need special attention.
Varicella vaccine is recommended after the first year of age in a single dose. Susceptible adolescents need 2 doses.