Varicella is a common childhood skin disease caused by a virus. The virus is called the Varicella-zoster virus (VZV).
Most people contract Varicella by age 15, the majority between ages 5 and 9, but all ages can contract it. Varicella is usually more severe in adults and very young infants than in children.
Primary infection with VZV causes Varicella. Following primary infection, VZV establishes latency in the dorsal root ganglia. Reactivation of the latent virus manifests as herpes zoster (shingles). Shingles is most commonly a disease of adults.
Varicella is highly contagious. It is easily passed between members of families and school classmates through airborne particles, droplets in exhaled air and fluid from the blisters or sores. It also can be transmitted indirectly by contact with articles of clothing and other items exposed to fresh drainage from open sores. Patients are contagious up to 5 days (more commonly, 1-2 days) before and 5 days after the date that their rash appears. When the sores have crusted over, the person is usually no longer contagious.
Symptoms tend to appear 14-16 days after the initial exposure but can occur any time from 10 days up to 21 days after contact with the virus. Varicella is characterized by one to two days of mild fever, general weakness and a rash, often the first sign of the disease. Rarely, a person may have the disease without the rash. The rash of Varicella develops in crops with raised red spots arriving first, progressing to blisters that burst, and creating open sores, before crusting over. This process usually starts on the scalp, then the trunk and finally the arms and legs. The rash is typically very itchy.
Acyclovir can be considered for otherwise healthy people who are at risk of moderate to severe varicella.
A vaccine to protect children against Varicella was first licensed in 1995. Persons 13 years of age and older who have never had Varicella or have not received the varicella vaccine should get two doses of the varicella vaccine at least 28 days apart.The varicella vaccine may be given along with the measles-mumps-rubella (MMR) vaccine in a combination called measles-mumps-rubella-varicella (MMRV).