Chicken pox was once an extremely common viral illness, particularly among children—approximately 4 million children were affected annually. Chicken pox is now very uncommon since the FDA approved the varicella-zoster vaccine in 1995. Children are administered the vaccine between 12 and 15 months and again between 4 and 6 years. It is characterized by itchy and tender blisters on the trunk, face and extremities. Chicken pox is caused by the herpes varicella zoster virus (VZV). It is highly contagious, but most cases are not dangerous.

Chicken pox can be passed on from 2 to 3 days before the rash appears until the blisters are crusted over. It spreads from exposure to infected people who cough, sneeze, share food or drinks or by touching the blisters. It is often accompanied by a headache, sore throat and possibly a fever. The incubation period (from exposure to first appearance of symptoms) is 14 to 16 days. When the blisters crust over, they are no longer contagious and the child can return to normal activity. This normally takes about 10 days after the initial appearance of symptoms.

It is important not to scratch the blisters as it can slow down the healing process and result in scarring. Scratching may also lead to another infection from bacteria. To help relieve the itching, patients are encouraged to soak in a cool bath. Children with chicken pox should get plenty of bed rest and can take over-the-counter analgesics to reduce pain and high fever.

Older children who have not been vaccinated can be effectively treated with two catch-up doses. Adults who have never had the illness should also be vaccinated.

The varicella zoster virus is the same virus that causes shingles in adults. It is caused by a reactivation of the dormant VZV brought on by stress, illness, sun-exposure and other stressors.