What Is Chickenpox?

Chickenpox was once considered a rite of passage for most children. And for many, this common and highly contagious disease — characterized by red, itchy spots on the skin — still occurs in childhood. In fact, it's estimated that about 4 million Americans, mostly children, contract chickenpox each year. Yet adults also can become infected.

Chickenpox is caused by the varicella-zoster virus, a type of herpes virus. This virus is easily spread from person to person through the air and physical contact. Outbreaks of chickenpox are common in late winter and early spring — periods of moderate temperatures when viruses thrive.

Most people think of chickenpox as a mild disease — and, for most, it is. In otherwise healthy children, chickenpox lasts 2 weeks or less and rarely causes complications. But for adults who've never been in contact with the virus and get sick later in life, chickenpox can be serious. Complications from chickenpox can result in hospitalization and can even be life-threatening.

Until 1995 — when a vaccine to prevent chickenpox became available — nearly everyone developed chickenpox in childhood. Today, children are routinely immunized against chickenpox. Vaccination against chickenpox is expected to greatly reduce the number of current and future cases.

Children's Conditions Center

Signs and Symptoms

Signs and symptoms of chickenpox include:

• Red, itchy rash. The best-known sign of chickenpox is a red, itchy rash that breaks out on the face, chest, back and — to a lesser extent — the arms and the legs. The rash usually appears a little less than 2 weeks after exposure to the virus and begins as superficial spots. These spots quickly turn into small blisters that break open and crust over. New spots continue to appear 5 to 7 days after the first spots, repeating the process. Itching may be mild or intense. If the disease spreads from child to child within a family, the intensity and extent of the rash may increase.
  
  
• Fever. A fever may begin 1 or 2 days before the rash. It's usually less than 101 F but may reach as high as 106 F — a sign to see a doctor.
  
  
• Runny nose, dry cough and irritability. All of these may precede the rash.
  
  
• Fatigue, weakness and mild headache. All of these may accompany the rash.

In otherwise healthy children, chickenpox usually runs its course in about 2 weeks.

Fever

Risk Factors

Chickenpox is highly contagious to those not immune to it and spreads quickly in child-care facilities, schools and within families. The virus is transmitted by direct contact with the rash or by droplets dispersed into the air by coughing or sneezing.

A person who has chickenpox can transmit the virus for up to 48 hours before the telltale rash appears and remains contagious until all spots crust over.

People who've been vaccinated against chickenpox are immune to the virus. Anyone who has had chickenpox is immune to future exposures. Those people at risk of contracting chickenpox include anyone who hasn't been vaccinated or who has never had the disease.

When to Seek Medical Advice

Because chickenpox is usually an uncomplicated infection in children, it ordinarily doesn't require a visit to the doctor. But do contact a doctor for yourself, another adult or a child if one or more of the following occur:

• The rash involves the eye.
  
  
• The rash gets very red, warm or tender, indicating a possible skin infection.
  
  
• The rash is accompanied by a fever higher than 103 F, dizziness, disorientation, rapid heartbeat, shortness of breath, tremors, loss of muscle coordination, worsening cough, vomiting or stiff neck.

Infants, teenagers and adults who aren't immune to chickenpox should be seen by a doctor if they're exposed to or develop chickenpox because of possible complications that can accompany the illness. A doctor can easily diagnose chickenpox by examining the characteristic rash and by noting the presence of other symptoms. But before bringing a child with chickenpox into a crowded waiting room and possibly infecting more children, phone your doctor's office to schedule an appointment.

Complications

Chickenpox is normally a mild disease. But it can be serious and lead to complications in these high-risk groups:

• Newborns and infants
  
  
• Teenagers
  
  
• Adults
  
  
• Pregnant women
  
  
• People whose immune systems are impaired by disease or suppressed by drugs

The most common complication from chickenpox is a bacterial infection of the skin. The next most common problems are pneumonia and encephalitis — inflammation of the brain — both of which can be very serious if not treated.

Chickenpox early on in pregnancy can result in birth defects, such as limb deformities. A great threat to the baby, though, occurs when the mother develops chickenpox a week before birth. Then it can cause a serious, life-threatening infection in the newborn. A pregnant woman who's not immune to chickenpox and has prolonged exposure to a person with the disease should consult with her physician about the risk to herself and her unborn child.

Anyone who has had chickenpox as a child is at risk for a latent complication called shingles. After an infection, some of the varicella-zoster virus may remain and hide in nerve cells. Many years later, the virus can reactivate and resurface as shingles — a painful band of short-lived blisters. About one in five adults who've had chickenpox experience shingles, usually after age 50. Children can develop shingles but do so less often than adults do. Rarely, a person with shingles can pass along the chickenpox virus to others who aren't immune.

Shingles can lead to its own complication — a condition in which the pain of shingles persists long after the blisters disappear. This complication, called postherpetic neuralgia, isn't contagious.

Pregnancy Center Chickenpox during pregnancy: Cause for concern? What Is Pneumonia? What Is Encephalitis? Shingles What Is Postherpetic Neuralgia?

Treatment

In otherwise healthy children, chickenpox typically requires no medical treatment. Some doctors prescribe antihistamines to relieve itching. But for the most part, the disease is allowed to run its course.

In people in high-risk groups for complications from chickenpox, doctors sometimes prescribe an antiviral drug such as acyclovir (Zovirax) to shorten the duration of the infection and help reduce the risk of complications. Another drug called varicella-zoster immune globulin, or VZIG, also may be given. It contains antibodies to the chickenpox virus.

If complications do develop, doctors treat those by type. Skin infections and pneumonia may be treated with antibiotics. Encephalitis is usually treated with antiviral drugs. Hospitalization may be necessary.

No one with chickenpox — child or adult — should receive any medicine containing aspirin because this combination has been associated with a disease called Reye's syndrome.

What Is Reye's Syndrome?

Prevention

The use of the varicella virus vaccine (Varivax) is the best way to prevent chickenpox. The vaccine has been available for use in the United States since 1995. According to the Centers for Disease Control and Prevention (CDC), the vaccine protects 90 percent to 100 percent of people who receive it.

Those advised by the CDC to receive the chickenpox vaccine include:

• Infants — the ideal time is between 12 and 18 months of age, as part of a routine immunization schedule
  
  
• Children, teenagers and adults who've never had chickenpox or been vaccinated — if you don't remember whether you've had chickenpox, a blood test can determine your immunity
  
  
• Teachers of young children, child-care employees and health care workers who may work with populations at risk of chickenpox

The vaccine is given in one dose to children 1 to 13 years of age. Those who are older are given two doses, 4 to 8 weeks apart. Protection is believed to last at least 10 to 20 years and perhaps longer, but it's unclear whether a booster shot may be necessary later in life. Many vaccines require booster doses. Time and study will tell if Varivax is one of them.

The vaccine isn't approved for use in pregnant women, people with weakened immunity or people who are allergic to gelatin or the antibiotic neomycin. Consult your doctor for more information about the varicella vaccine. Women who are planning on becoming pregnant should be up-to-date on their vaccinations before conceiving a child.

Parents typically wonder whether vaccines are safe. Since it became available, several million doses of the varicella vaccine have been given to children in the United States. Studies continue to show the vaccine to be safe and effective. Side effects are generally mild and include redness, soreness, fatigue, nausea and, rarely, small bumps at the site of the shot.

If you've had chickenpox, you don't need the vaccine. You're immune to future exposures for life. However, it may be possible that if you had a very mild infection as a child that your body may not have built up an adequate amount of antibodies to prevent a second infection. Or you may assume that you had chickenpox as a child when you actually didn't, putting you at risk of infection later in life.

Chickenpox vaccine Childhood illnesses: Prevent the 7 usual suspects

Self-Care

To help ease the symptoms of uncomplicated chickenpox, follow these simple self-care measures:

• Don't scratch. Scratching can slow healing of the sores, cause scarring and increase the risk that the sores will become infected. To lessen irritation when your child scratches, trim his or her fingernails. Put gloves on the child's hands at night to prevent scratching. If itching is particularly severe or irritating, you may want to talk to your doctor about using an over-the-counter antihistamine for relief.
  
  
• Take baths. Cool baths every 3 to 4 hours also can help relieve itching and provide a playful diversion for a young child. Sprinkle uncooked oatmeal or baking soda in the bath water for added relief.
  
  
• Apply lotion. Applying calamine lotion to the spots may help relieve the itching.
  
  
• Rest and eat a bland diet, if necessary. Getting plenty of rest is helpful in getting over any infection. If chickenpox sores develop in the mouth, switch to a diet of soft, bland foods. Spicy, acidic or hard and crunchy foods can be irritating to mouth sores.
  
  
• Treat a fever. Fever can be reduced with acetaminophen (Tylenol, others). But medications such as acetaminophen and ibuprofen (Advil, Motrin, others) are not antiviral. Don't give aspirin to anyone with chickenpox because it can lead to a serious disease called Reye's syndrome. Lukewarm — not cold — baths also can help bring down a fever.

What Is Reye's Syndrome?

Coping skills

Chickenpox is likely to keep your child home for 1 or 2 weeks. This can lead to several issues, including how to prevent boredom. You may also need to balance the need to care for your child with the demands of going to work.

When staying home with your child, plan some low-key activities that your child will enjoy. These can be things you don't normally have time to do, such as reading an extra book out loud.

If your child is sick and you feel pressure to return to work, recruit help from your partner or from other relatives and friends. Perhaps your employer will let you work from home. Also check with your union or company policies on care of a sick child.

A sick child and a demanding job: Balancing caregiving with work

— October 2, 2002 —