Chickenpox (varicella) is a common childhood disease caused by the herpes varicella virus that causes a blister-like rash, itching, tiredness, and fever.


for searching the Internet and other reference sources



What Is Chickenpox?

With its rash and fever, chickenpox is common in children and usually mild. But it can be serious, especially in infants, adults, and people with weak immune systems * . Chickenpox is caused by varicella (var-i-SELL-a), a virus in the herpesvirus family.

The chickenpox virus spreads from person to person by contact with the fluid in chickenpox blisters or through droplets in the air. It is very contagious. About 4 million people in the United States get chickenpox each year; about 10,000 of these people get sick enough to go to the hospital, and about 100 die. Chickenpox is most common in children under the age of 15, but anyone can get it. Most cases occur in the late winter or spring.

Immunization of children with the chickenpox vaccine now available is expected to decrease cases of the disease dramatically over the next few years.

What Are the Symptoms of Chickenpox?

The first sign of chickenpox may be a cough, an achy feeling, or a runny nose. Then a rash develops that looks like red spots. This rash forms blisters that dry and become scabs within four to five days. The rash usually starts on the chest, back, and face, but it usually spreads over the whole body. A person may have anywhere from just a few itchy spots to more than 500. Along with the rash, the person may have a fever and feel tired. Symptoms are usually more severe in adults.

Serious problems resulting from chickenpox are also more common in adults. In some people, the chickenpox virus can lead to pneumonia (noo-MO-nee-a), an inflammation of the lungs. In other people, it can lead to encephalitis (en-sef-a-LY-tis), an inflammation of the brain. In rare cases, the result can be brain damage or even death. Scratching the itchy rash can cause scars and sometimes a bacterial germ infection of the skin that can spread through the body and cause high fever.

A person can give chickenpox to someone else from one or two days before the rash starts until all the blisters have formed scabs. The disease will show up 10 to 21 days after contact with the sick person.

What Are the Long-Term Risks?

Even after a person gets over chickenpox, the virus does not go away. It lives on in an inactive or dormant state within the nerve roots of the person's body. The virus can reawaken many years later to cause shingles, a disease that usually starts with a tingling feeling, itching, or severe pain in the skin. Within days, a blister-like rash forms. The pain can last for weeks, months, or years after the rash heals. A person can catch chickenpox from someone with shingles, but can't catch shingles itself

A boy with chickenpox. © John D. Cunningham, Visuals Unlimited
A boy with chickenpox.
© John D. Cunningham, Visuals Unlimited

* immune system is the body's defense system for fighting off attacks by viruses, bacteria, fungi, and other foreign substances that can cause illness or hurt the body.

When Is a Doctor Needed?

Chickenpox is usually a mild disease. However, there are still times when it is important to talk to a doctor:

  • If a fever lasts longer than four days
  • If a fever rises above 102 degrees Fahrenheit
  • If an area of rash leaks pus or becomes more red, warm, swollen, or sore.

It is important to call a doctor right away if the person with chickenpox seems extremely ill or develops any of these problems:

  • Trouble waking up
  • Confusion
  • Trouble walking
  • Stiff neck
  • Repeated vomiting
  • Severe cough
  • Trouble breathing

A young child may develop chickenpox blisters in his or her mouth and throat. This makes eating and drinking very uncomfortable. Refusing to drink can lead to dehydration * , especially in very small children with a fever, and this must be treated by a doctor.

How Is Chickenpox Treated?

To treat a fever, people who have chickenpox should take only nonaspirin medicines such as acetaminophen (a-set-a-MIN-o-fen). They should never take aspirin or products that contain aspirin. The use of aspirin by people with a virus-caused illness such as chickenpox has been linked to Reye's (RIZE) syndrome, a serious disease that affects the whole body, especially the liver and brain.

Scratching a chickenpox rash can cause a skin infection. People with chickenpox should try not to scratch, and they should keep their fingernails clean and cut short. Oatmeal baths and a soothing lotion called calamine (KAL-a-mine) lotion may help relieve the itching.

Acyclovir (ay-SY-klo-veer) is a drug that fights the chickenpox virus. Because this drug can have side effects, doctors usually prescribe it for people who are at high risk for severe symptoms. This includes people with long-term skin or lung diseases, those with diseases or taking medicines that weaken the immune system, and anyone over age 12, since at that age chickenpox can be more severe than for younger children. To be helpful, this drug must be started very soon after the rash first appears.

* dehydration (dee-hy-DRAY-shun) is loss of fluid from the body.

Can Chickenpox Be Prevented?

In the past, almost everyone got chickenpox by the time they reached adulthood. Since 1995, however, there has been a vaccine against chickenpox. A vaccine is a preparation given to people to prevent a disease. This vaccine does not give 100 percent protection, but eight or nine out of every ten people who get it are protected from the disease. People who do catch chickenpox after getting the vaccine usually have a very mild case with few itchy spots, a mild fever, and a fast recovery.

The vaccine is recommended as part of the usual immunizations of childhood. Also, people 13 years old and older who have not had chickenpox should get this vaccine. People who have already had chickenpox do not need the vaccine, because they cannot get the disease again.

Many adults do not remember if they have had chickenpox. These people can have a blood test to check for signs that they have had the disease. If this test is not available, though, it is usually safe to receive the vaccine, even if a person has already had chickenpox.

Some people should not take the vaccine, however. These include women who are pregnant, people who currently have a serious illness, those who have a weak immune system, and people who have received a blood transfusion in the past five months.

See also
Reye's Syndrome
Viral Infections



Silverstein, Alvin, Virginia Silverstein, Laura Nunn. Chickenpox and Shingles. Springfield, NJ: Enslow Publishers, 1998.


U.S. Centers for Disease Control and Prevention (CDC), National Immunization Program, 1600 Clifton Road N.E., Atlanta, GA 30333. A government agency that offers information on chickenpox.
Telephone 800-CDC-SHOT

American Academy of Pediatrics, 141 Northwest Point Boulevard, Elk Grove Village, IL 60007-1098. The American Academy of Pediatrics posts a fact sheet about chickenpox vaccine at its website.
Telephone 847-228-5005

VZV Research Foundation, 40 East 72nd Street, New York, NY 10021. This is a group that studies chickenpox and shingles.
Telephone 800-472-VIRUS

Also read article about Chickenpox from Wikipedia

User Contributions:

Comment about this article, ask questions, or add new information about this topic: