What is chickenpox?

Chickenpox is an illness with rash and fever caused by the varicella-zoster virus.

What are the signs or symptoms?

Rash (ie, small red or dark spots and bumps developing into very small fluid-filled sacs on the skin [vesicles] over 3?4 days and then forming scabs or "crusts").
Discrete groupings ("crops") of vesicles will develop over several days. Someone who has chickenpox for more than a day will have some red bumps, vesicles, and scabbed-over vesicles all at the same time.
Rash may appear inside the mouth, ears, genital areas, and scalp.
The rash is usually quite itchy.
Fever, runny nose, cough.

What are the incubation and contagious periods?

Incubation period: Usually 14 to 16 days; occasionally as short as 10 days and as long as 21 days after contact.
Contagious period: Chickenpox is highly contagious to people who have not previously been vaccinated or had the disease. The most contagious period is while the rash is spreading; a child may also be contagious 1 to 2 days before the rash appears. The contagious period ends when all the vesicles have scabbed or crusted over and no new vesicles are forming.
Although uncommon, a previously immunized person can have a mild form of chickenpox, which is contagious.

How is it spread?

Contact with the skin vesicles of someone with chickenpox or an uncovered shingles rash (see Shingles [Herpes Zoster] Quick Reference Sheet).
Transmission occurs when the virus becomes airborne from fluid released from vesicles or from small respiratory droplets expelled after a cough or sneeze. These germ-containing particles can quickly dry out in the air and settle onto surfaces, later attaching to dust particles and becoming airborne again. Air currents can carry the particles and can infect people in the same or another room. Even brief exposure or shared airflow poses a high risk of infection for individuals who have not had chickenpox before, have not been protected by the chickenpox vaccine, or have a weakened immune system.

Chickenpox rash on a child

AMERICAN ACADEMY OF PEDIATRICS, COURTESY OF EDGAR O. LEDBETTER, MD

Several pink and red diffuse small red spots and bumps; small fluid-filled sacs, or vesicles; and a few scabbed vesicles of varying sizes in discrete groupings spread across a child's chest and arm with raised white centers.

Chickenpox lesions on the face of a 4-year-old

AMERICAN ACADEMY OF PEDIATRICS, COURTESY OF PAUL WEHRLE, MD

About 50 diffuse fluid-filled bumps, pink and red in color, on the face of a 4-year-old across his forehead, nose, and lips.

How do you control it?

Chickenpox is a vaccine-preventable infection. Immunize according to the current schedule—when a child is 12 to 15 months of age and with a second dose at 4 to 6 years of age.
Vaccinate older children, teens, and adults who are susceptible (ie, those who have not received 2 doses of vaccine or who have not had the natural infection—the occurrence of a natural infection will need to be determined by a health professional).
Exclude infected children and educators until entire rash is crusted over and no new lesions appear within a 24-hour period.
Use good hand-hygiene technique at all the times listed in Chapter 2 and after any contact with soiled articles or skin vesicles.
Use proper surface-sanitation techniques at all the times listed in Chapter 2.
Ventilate room air with fresh outdoor air.

What are the roles of the educator and the family?

Report the infection to the staff member designated by the early childhood education (ECE) program or school for decision-making and action related to care of ill children and staff members. That person, in turn, alerts possibly exposed family and staff members and the parents of underimmunized children to watch for symptoms and notifies the Child Care Health Consultant.
Report the infection to the local health department. The health professional who makes the diagnosis may not report that the infected child is a participant in an ECE program or school, and this could lead to a delay in controlling the spread.
Specifically notify all adults (staff members and volunteers) who have not had chickenpox or 2 doses of the chickenpox vaccine, as well as families of exposed children who are underimmunized against chickenpox, to contact their health care professionals. Within 24 hours of exposure, be sure to advise those who might be pregnant or have a problem with their immune system to check with their health professionals about what to do. Pregnant individuals who have previously had chickenpox infection or vaccination should not have a pregnancy-related problem if exposed to chickenpox. However, pregnant individuals should be encouraged to confirm their protection with their own health professionals. Adults and children need to have had a previous known illness with chickenpox (documented by a health care professional) or 2 doses of chickenpox vaccine for full protection.
Do not give aspirin to ill children, as it may increase their risk of contracting Reye syndrome, a serious complication associated with the use of aspirin in someone infected with chickenpox and other viral illnesses (eg, influenza).

Exclude from educational setting?

Yes.

For children with chickenpox or shingles and the associated rash: Chickenpox is a highly communicable illness for which routine exclusion of infected children is warranted. See the Comments section for information about shingles, vaccine-related chickenpox, and chickenpox in previously vaccinated children.
For exposed children who have not received the chickenpox vaccine and have not developed a rash: Exclude from day 8 to 21 after the day of exposure. Contact the local health department to determine which children qualify as being exposed. Children exposed to chickenpox are not contagious during days 1 to 7 after exposure.

Readmit to educational setting?

Yes, when all the following criteria are met:

For children with a rash: When all vesicles have scabbed over and no new lesions have appeared within 24-hour period (usually at least 5 days after start of rash)
For immunized children who have a mild infection without crusts: once no new bumps have appeared for at least 24 hours
For underimmunized children: After 21 days, or once they have become vaccinated or develop a rash and all vesicles have developed scabs
When the child is able to participate and staff members determine they can care for the child without compromising their ability to care for the health and safety of the other children in the group and no new lesions appear within a 24-hour period

Comments

Initial chickenpox infections in adults can be extremely serious and may result in death.
The chickenpox virus remains in an inactive form in the body's nerve cells for a lifetime. Shingles (herpes zoster) occurs when someone has fully recovered from chickenpox and, later, the inactive virus in their body's nerve cells becomes active (see Shingles [Herpes Zoster] Quick Reference Sheet).
A rash after varicella vaccination may occur in 3% to 5% of children 5 to 26 days after vaccination. This mild condition usually results in a few red bumps at or near the injection site or very widely scattered bumps over the entire body. Bumps near the injection site may be covered with a nonporous bandage and clothing, and the child may continue to participate. In a child with a more widespread rash, the child might have been exposed to natural chickenpox and become infected before the vaccine had time to work. A pediatric health professional should decide when a child with a widespread rash can continue to participate in an ECE program or school.
Rarely, children get chickenpox a second time. These cases usually are very mild with less fever and fewer bumps and blisters than the first time. However, these children are still contagious and should not come to an educational setting until the vesicles scab over.
It is possible for children to get chickenpox despite being vaccinated. The first dose of this vaccine is about 85% effective at preventing mild chickenpox and 97% effective at preventing severe chickenpox. Two doses of vaccine are recommended and are much more effective than 1 in preventing infection. When vaccinated children do contract chickenpox, the illness is usually milder, with less fever and fewer bumps or vesicles than in underimmunized children. However, these children are still contagious and should remain home until all vesicles have scabbed over and no new lesions have appeared for at least 24 hours.

Disclaimer

Adapted from Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide, 7th Edition.

The American Academy of Pediatrics (AAP) is an organization of 67,000 primary care pediatricians, pediatric medical subspecialists, and pediatric surgical specialists dedicated to the health, safety, and well-being of all infants, children, adolescents, and young adults.

Any websites, brand names, products, or manufacturers are mentioned for informational and identification purposes only and do not imply an endorsement by the American Academy of Pediatrics (AAP). The AAP is not responsible for the content of external resources. Information was current at the time of publication. The information contained in this publication should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.

Chickenpox (Varicella-Zoster Infections)—Child Care and Schools