Chickenpox

Definition

Chickenpox is a virus that spreads easily to others. It creates a widespread, itchy rash. The infection can also cause serious complications in some people.

Chickenpox

Causes

Chickenpox is caused by the varicella-zoster virus (VZV). It spreads from person to person via:

Airborne droplets of moisture containing the VZV virus
Direct contact with fluid from a chickenpox or zoster rash

It is contagious 1-2 days before the rash erupts. It remains contagious until all of the blisters have crusted. This takes five days. It is most contagious just after the rash has broken out.

A pregnant mother can transmit the virus to a fetus.

Risk Factors

Factors that increase your chance of getting chickenpox include:

Close contact with an infected person, unless you have been vaccinated or have already had chickenpox
Age: less than three years old, with peak incidence between 5-9 years old
Immune-deficient state, such as having leukemia, an organ transplant, high-dose steroid use, or HIV
Cancer
Pregnancy
Time of year—late winter, early spring

Symptoms

Symptoms break out about 10-21 days after contact. They are more severe in adults than they are in children.

Initial symptoms include:

Mild headache
Moderate fever
Cough
Sore throat
Severe itch
Lack of appetite
General feeling of discomfort
Some children complain of abdominal pain

The rash appears within 1-2 days after the first symptoms. The rash:

Begins with small, flat, red spots:
- Spots become raised and form a round, intensely itchy, fluid-filled blister
- Blisters develop in clusters, with new clusters forming over 5-6 days
Usually develops into patches on the skin above the waist, including the scalp
May also appear on the eyelids, in the mouth, upper airway, voice box, or on the genitals
Typically crusts over by day six or seven and disappears within three weeks

Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done. Diagnosis is usually based on the rash and your age. Blood and lab tests to identify the virus are rarely needed.

Treatment

Chickenpox is mild in most people. It will naturally run its course. In these cases, treatment focuses on relieving the symptoms.

To Reduce Itching

Apply wet compresses to the skin
Apply over-the-counter anti-itch creams or lotions
Take oatmeal baths
Take an oral antihistamine

Note: Aspirin is not recommended for children or teens with a current or recent viral infection. This is because of the risk of Reye's syndrome. Ask your doctor which other medicines are safe for your child.

Antibiotics

Antibiotics cannot cure infections caused by a virus. They may be given if the rash becomes infected with bacteria.

Antiviral Medication

The course, severity, and duration of the infection may be reduced by antiviral medications, such as:

Acyclovir
Valacyclovir
Famciclovir

They are often used in:

Adolescents, adults, and individuals with weak immune systems
Individuals with chronic skin or lung diseases and those taking aspirin or steroids

Special Needs

Varicella-zoster immune globulin is often given immediately after exposure. It is reserved for newborns and people with weak immune systems.

Prevention

Avoid contact with anyone who has chickenpox. This is very important if you have not been vaccinated against the infection.

Vaccination in Children

The varicella vaccine, or a combination vaccine called MMRV, is recommended for most children. MMRV protects against measles, mumps, rubella, and varicella.

There is a catch-up schedule if your child has missed the routine injections.

Vaccination in Adults

Adults who have never had chickenpox or received the varicella vaccine should be vaccinated.

Vaccination After Exposure

If you or your child has not been vaccinated, but are exposed to chickenpox, a vaccine given right away may help lessen the severity of the infection, or prevent the infection.

RESOURCES

American Academy of Family Physicians http://familydoctor.org

Centers for Disease Control and Prevention http://www.cdc.gov

CANADIAN RESOURCES

AboutKidsHealth http://www.aboutkidshealth.ca

College of Family Physicians of Canada http://www.cfpc.ca

References

Baker CJ, Pickerling LK, et al. Advisory Committee on Immunization Practices. Recommended adult immunization schedule: United States, 2011. Ann Intern Med. 2011;154(3):168-173.

Centers for Disease Control and Prevention. Recommended immunization schedules for persons aged 0-18 years—United States, 2011. MMWR. 2011;60(5).

Gales SA, Sweet A, et al. The safety profile of varicella vaccine: a 10-year review. J Infect Dis. 2008;197(Suppl2):S165-9).

Marin M, Meissner HC, et al. Varicella prevention in the United States: a review of successes and challenges. Pediatrics. 2008;122: e744-51.

A New Product (VariZIG) for Postexposure Prophylaxis of Varicalla Available under an Investigational New Drug Application Expanded Access Protocol. MMWR. 2006;55: 209-210.

Skull SA, Wang EE. Varicella vaccination: a critical review of the evidence. Arch Dis Child. 2001;85:83-90.

Varicella (chickenpox) vaccination. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/vaccines/vpd-vac/varicella/default.htm. Accessed May 30, 2013.

Vazquez M, LaRussa PS, et al. Effectiveness over time of varicella vaccine. JAMA. 2004;291:851-855.

1/31/2008 DynaMed's Systematic Literature Surveillance. Available at: http://dynamed.ebscohost.com/about/about-us: Centers for Disease Control and Prevention. Recommended immunization schedules for persons aged 0-18 years—United States, 2008. MMWR. 2008;57;Q1-Q4. Centers for Disease Control and Prevention, MMWR website. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5701a8.htm. Updated January 10, 2008. Accessed January 28, 2008.

10/14/2008 DynaMed's Systematic Literature Surveillance. Available at: http://dynamed.ebscohost.com/about/about-us: Macartney K, McIntryre P. Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults. Cochrane Database Syst Rev. 2008;(3):CD001833.

Revision Information

Reviewer: Michael Woods, MD
Review Date: 05/2013 -
Update Date: 05/30/2013 -

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