What is happening inside my child’s body? Getting chicken pox is almost inevitable during childhood — or at least it used to be. Chicken pox, also called varicella, is a viral infection that causes fever and a rash that evolves from red spots to blisters to scabs over 48 to 72 hours. The hallmark of this illness is that spots of all ages are clearly visible, from young and pink to old and crusted. The spots are small, ranging from 1 to 5 millimeters.
Because the rash tends to be extremely itchy, children will often scratch and unroof the blisters. When this happens, the open sores can become infected with bacteria. Infected pox are more likely to scar. The open skin also provides an entry point for bacteria into the body, creating the potential for more serious complications.
Chicken pox is very contagious. If your child has skin-to-skin (or face-to-face) contact with a child who is infected with chicken pox, the virus can be transmitted easily. For this reason, a child with chicken pox is considered contagious until every last pock has scabbed over. But the contagious period begins before the first pock even appears. In the earliest part of the illness, before the rash emerges, the virus is shed through respiratory droplets. A respiratory droplet is a tiny particle of moisture that comes out of the mouth with a cough. The older the child with chicken pox, the more vigorously she can cough, and the farther a respiratory droplet can fly. With the combination of coughing and rubbing a runny nose with bare hands, the virus lands on doorknobs, toys, and just about anywhere else you can imagine.
The incubation period for chicken pox is 10 to 21 days. This means that if your child is going to get chicken pox, she will develop the rash and fever 1 to 3 weeks after exposure.
In years past, parents often had “chicken pox parties.” These gatherings were an effort to expose children who had never had chicken pox to a child who had a new case in hopes that the uninfected children might pick up the infection. Now that the chicken pox vaccine is available and the potential seriousness of the illness is appreciated, chicken pox parties are a rare occurrence.
The chicken pox vaccine, called Varivax, has recently become part of the standard childhood vaccine schedule. It is strongly recommended (and in most states required) prior to entry into kindergarten or day care. This vaccine has been in used for decades in Japan. It has become increasingly popular in the United States in the past 10 years. About 10 percent of the children who get the vaccine may still get chicken pox, but they will get a significantly milder case with a much lower risk of a secondary infection or other complications.
Shingles is a reactivation of chicken pox. Once a person has had chicken pox, the virus remains dormant in the body, housed in compartments called ganglia located along specific nerves. When the body is under significant stress — for instance, when it is fighting an infection or when the immune system is suppressed — the virus located in the ganglion nerve roots can reactivate, traveling along the nerves to the skin. The rash that appears looks very similar to the original chicken pox rash, starting as small red spots and then becoming blisters and eventually scabs. However, unlike chicken pox, the shingles rash appears only in the specific segment of skin served by that one nerve root. Therefore, the rash is isolated. Also, with shingles, the activated nerve tingles or burns as the virus is moving along it. This is why shingles tend to hurt as well as itch.