Chickenpox

Chickenpox is a highly infectious disease, usually associated with childhood. By adulthood, more than 95 percent of Americans have had chickenpox.

The disease is caused by the varicella-zoster virus (VZV), a form of the herpes virus. Transmission occurs from person-to-person by direct contact or through the air.

Chickenpox most commonly occurs in children between the ages of 5 and 9, but in the US, chickenpox is most common in children between the ages of 1 and 4. This difference can be linked to the proportion of children in this age group who are in daycare.

What are the symptoms of chickenpox?

Symptoms are usually mild among children, but may be life threatening to infants, adults, and people with impaired immune systems. The following are the most common symptoms of chickenpox. However, each child may experience symptoms differently. Symptoms may include:

• Fatigue and irritability one to two days before the rash begins
• Itchy rash on the trunk, face, under the armpits, on the upper arms and legs, and inside the mouth
• Fever
• Feeling ill
• Decreased appetite
• Muscle and/or joint pain
• Cough or runny nose

The symptoms of chickenpox may resemble other skin problems or medical conditions. Always consult your child's physician for a diagnosis.

How is chickenpox spread?

Once infected, chickenpox may take 10 to 21 days to develop. Chickenpox is contagious for one to two days before the appearance of the rash and until the blisters have dried and become scabs. The blisters usually dry and become scabs within four to five days of the onset of the rash. Children should stay home and away from other children until all of the blisters have scabbed over.

Family members who have never had chickenpox have a 90 percent chance of becoming infected when another family member in the household is infected.

How is chickenpox diagnosed?

Chickenpox is usually diagnosed based on a complete medical history and physical examination of your child. The rash of chickenpox is unique, and usually a diagnosis can be made from a physical examination.

Treatment for chickenpox:

Specific treatment for chickenpox will be determined by your child's physician based on:

• Your child's age, overall health, and medical history
• extent of the condition
• Your child's tolerance for specific medications, procedures, or therapies
• expectations for the course of the condition
• Your opinion or preference

Treatment for chickenpox may include:

• Acetaminophen for fever. Do not give aspirin to a child without first contacting the child's physician. Aspirin, when given as treatment for children, has been associated with Reye syndrome, a potentially serious or deadly disorder in children. Therefore, pediatricians and other healthcare providers recommend that aspirin (or any medication that contains aspirin) not be used to treat any viral illnesses in children.
• Antibiotics for treating bacterial infections
• Calamine lotion (to relieve itching)
• Antiviral drugs (for severe cases)
• Bed rest
• Increased fluid intake (to prevent dehydration)
• Cool baths with baking soda or Aveeno (to relieve itching)

Children should not scratch the blisters, as this could lead to secondary bacterial infections. Keep your child's fingernails short to decrease the likelihood of scratching.

The chickenpox vaccine

Since 1995, a chickenpox vaccine has been available for children 12 months of age and older. Adolescents and adults who have never had chickenpox can also get the vaccine. The vaccine has proven very effective in preventing severe chickenpox. The CDC Advisory Committee on Immunization Practices, the American Academy of Pediatrics, and the American Academy of Family Physicians recommend that all children be vaccinated with the chickenpox vaccine between 12 and 18 months of age.

A booster vaccination is recommended again between 11 and 12 years of age. Many schools now require vaccination prior to entry into preschool or public schools.

Immunity from chickenpox:

Most individuals who have had chickenpox will be immune to the disease for the rest of their lives. However, the virus remains dormant in nerve tissue and may reactivate, resulting in herpes zoster (shingles) later in life. Sometimes, a secondary case of chickenpox does occur. Blood tests can confirm immunity to chickenpox in people who are unsure if they have had the disease.

What complications are commonly associated with chickenpox?

Complications can occur from chickenpox. Those most susceptible to severe cases of chickenpox are infants, adults, pregnant women (unborn babies may be infected if the mother has not had chickenpox prior to pregnancy), and people with impaired immune systems. Complications may include:

• Secondary bacterial infections
• Pneumonia
• Encephalitis (inflammation of the brain)
• Cerebellar ataxia (defective muscular coordination)
• Transverse myelitis (inflammation along the spinal cord)
• Reye syndrome (a serious condition which may affect all major systems or organs)
• Death