What is Chickenpox?

Chickenpox is an illness caused by infection with the varicella-zoster (Chickenpox) virus. It is a highly contagious and common childhood disease. The virus causes skin eruptions (rash) that begin as a reddened spot on the skin, enlarge into a fluid-filled blister (called a vesicle) and then crust or scab over after several days. The eruptions commonly appear in several successive "crops" so that several stages of the rash can be present at the same time. The disease is usually mild, however severe cases and complications such as pneumonia or death can occur. Most outbreaks of Chickenpox occur in the winter and early spring.

Who gets Chickenpox?

Anyone who has not had Chickenpox disease, or has not had the Chickenpox vaccine can get chickenpox disease. Once an individual has been infected with the Chickenpox virus, he/she is usually immune for the rest of his/her life. Second attacks of Chickenpox are rare, but they do occur. In most communities, at least 90% of the population has been infected with the chickenpox virus by age 15.

How is Chickenpox spread?

Chickenpox is spread from person-to-person through direct contact with the skin rash (vesicles or blisters and secretions), or through the air by inhaling respiratory droplets. Respiratory droplets containing chickenpox virus are released into the air through sneezing or coughing by a person ill with chickenpox. Once all vesicles on the skin have completely crusted over, an individual can no longer transmit chickenpox to others through either route.

What are the symptoms of Chickenpox?

The initial symptoms of chickenpox are tiredness, weakness and fever. These symptoms are followed by the rash which consists of eruptions that begin as a reddened spot on the skin, enlarge into a fluid-filled blister (called a vesicle) and then crust or scab over after several days. The eruptions commonly appear in several successive "crops" so that several stages of the rash can be present at the same time. The eruptions tend to be more abundant on clothing-covered areas of the body rather than exposed areas. The rash may cause moderate to intense itching. The rash may appear on the scalp, under the arms, or on the mucous membranes of the mouth, throat and eyelids.

How soon do symptoms occur?

Symptoms generally occur between 13 and 17 days after exposure to an infected person.

How is Chickenpox diagnosed?

Chickenpox is most often diagnosed by its clinical appearance. A blood test for Chickenpox is available but it is usually not necessary.

What is the treatment for Chickenpox?

There is no drug to cure Chickenpox once symptoms have begun. Mild cases require only treatment to control itching to prevent scratching that could lead to a secondary bacterial skin infection. Severe cases may require hospitalization.

How long is an infected person infectious to others?

An infected person is capable of transmitting Chickenpox to others from about 3 days before the skin rash first appears (through respiratory droplets), to about 7 days after the rash first appeared, or until all the skin blisters (vesicles) have crusted over.

What are the long-term consequences of Chickenpox infection?

For most individuals, there are no long-term consequences of Chickenpox infection. However, Chickenpox illness in a pregnant woman may cause deformities in the unborn child (known as Congenital Varicella Syndrome).

Should an infected person be excluded from work or school?

Individuals with Chickenpox disease should remain at home or away from susceptible persons for at least 6 days after the skin eruptions first appeared, or until the blisters (vesicles) have crusted over, whichever comes earlier.

How can Chickenpox be prevented?

Chickenpox can be prevented by vaccinating susceptible children (those who have never had Chickenpox) with the Chickenpox vaccine. All children should be routinely vaccinated with this vaccine at 12 to 18 months of age. All susceptible children should be vaccinated by their 13th birthday. Vaccination is also recommended for susceptible adolescents, adults, and health-care workers and family contacts of immunocompromised persons.

Varicella-zoster immune globulin is recommended for certain individuals if they are exposed to someone with Chickenpox illness. These individuals are those at high risk of developing complications from Chickenpox disease (such as pregnant women and individuals with immune deficiencies). The immune globulin must be given within 96 hours of exposure for it to be effective.