• Home

Home > Medical Reference > Encyclopedia (English)

Toggle: English / Spanish

Chickenpox

• Overview
• Symptoms
• Treatment
• Prevention

Definition:

Chickenpox is one of the classic childhood diseases, and one of the most contagious. The affected child or adult may develop hundreds of itchy, fluid-filled blisters that burst and form crusts. Chickenpox is caused by a virus.

The virus that causes chickenpox is varicella-zoster, a member of the herpesvirus family. The same virus also causes herpes zoster (shingles) in adults.

Alternative Names:

Varicella

Causes, incidence, and risk factors:

In a typical scenario, a young child is covered in pox and out of school for a week. The first half of the week the child feels miserable from intense itching; the second half from boredom. Since the introduction of the chickenpox vaccine, classic chickenpox is much less common.

Chickenpox is extremely contagious, and can be spread by direct contact, droplet transmission, and airborne transmission. Even those with mild illness after the vaccine may be contagious.

When someone becomes infected, the pox usually appear 10 to 21 days later. People become contagious 1 to 2 days before breaking out with pox. They remain contagious while uncrusted blisters are present.

Once you catch chickenpox, the virus usually remains in your body for your lifetime, kept in check by the immune system. About 1 in 10 adults will experience shingles when the virus re-emerges during a period of stress.

Most cases of chickenpox occur in children younger than ten. The disease is usually mild, although serious complications sometimes occur. Adults and older children usually get sicker than younger children do.

Children under one year of age whose mothers have had chickenpox are not very likely to catch it. If they do, they often have mild cases because they retain partial immunity from their mothers' blood. Children under one year of age whose mothers have not had chickenpox, or whose inborn immunity has already waned, can get severe chickenpox.

The pox are worse in children who have other skin problems, such as eczema or a recent sunburn.

Complications are more common in those who are immunocompromised from an illness or medicines like chemotherapy. Some of the worst cases of chickenpox have been seen in children who have taken steroids (for example, for asthma) during the incubation period, before they have any symptoms.

References:

Long SS. Principles and Practice of Pediatric Infectious Disease . 2nd ed. St. Louis, MO: Elsevier; 2003.

Chen TM. Clinical manifestations of varicella-zoster virus infection. Dermatol Clin . 2002; 20(2): 267-282.

Burton A. Vaccine vanquishes varicella. Lancet Infect Dis . 2002; 2(4): 202.

American Academy of Pediatrics. Committee on Infectious Diseases. Varicella vaccine update. Pediatrics . 2000 Jan;105(1 Pt 1):136-41. Review.

• Review Date: 8/23/2005
• Reviewed By: John Goldenring, MD, MPH, Department of Pediatrics, Children's Hospital, San Diego, CA. Review provided by VeriMed Healthcare Network.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process . A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2007 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.