Chickenpox

Chickenpox is spread by breathing in respiratory droplets spread through the air by a cough or sneeze of an infected individual. Contact with the fluid from skin lesions can also spread the virus. The incubation period—or the time from exposure to VZV to the onset of the disease—is about 14-15 days. The most contagious period is just prior to the appearance of the rash, and early in the illness when fresh pox are still appearing. The first sign of chickenpox in children is often the appearance of the chickenpox rash. Adults and some children may have a prodrome, or series of warning symptoms. This prodrome is typical of the flu, and includes headache, fatigue, backache, and a fever. The onset of the rash is quite rapid. First, small red "dots" appear on the skin. Soon, a vesicle containing clear fluid appears in the center of the dot. This small, reddish bump with a central clear fluid is sometimes referred to as "dewdrop on a rose petal" appearance. The vesicle rapidly dries, forming a crust. This cycle, from the appearance of the dot to the formation of the crust, can take place within eight to 12 hours. As the crust dries, it falls off, leaving a slight depression that eventually recedes. Scarring from chickenpox is rare.

Over the course of a case of chickenpox, an individual may develop between 250 and 500 skin lesions. The lesions occur in waves, with the first set of lesions drying up just as successive waves appear. The waves appear over two to four days. The entire disease runs its course in about a week, but the lesions continue to heal for about two to three weeks. The lesions first appear on the scalp and trunk. Most of the lesions in chickenpox are found at the center of the body; few lesions form on the soles and palms. Lesions are also found on the mucous membranes, such as the respiratory tract, the gastrointestinal tract, and the urogenital tract. Researchers think that the lesions on the respiratory tract may help transmit the disease. If a person with respiratory lesions coughs, they may spray some of the vesicle fluid into the atmosphere, to be breathed by other susceptible persons.

Although the lesions look serious, chickenpox in children is usually a mild disease with few complications and a low fever. Occasionally, if the rash is severe, the fever may be higher. Chickenpox is more serious in adults, who usually have a higher fever and general malaise. The most common complaint about chickenpox from both children and adults is the itching caused by the lesions. It is important not to scratch the lesions, as scratching may cause scarring.