Chickenpox

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(Varicella)

Definition

Chickenpox is a viral infection. It is highly contagious. It creates a widespread, itchy rash. The infection can also cause serious complications in some people. Chickenpox is more dangerous for adults and newborns. It is also a danger for people with suppressed immune systems.
Chickenpox
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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 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, 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 malaise
  • Some children complain of abdominal pain
The rash appears within 1-2 days after the first symptoms. The rash will:
  • Consist at first of 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 develop into crops 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

  • Wet compresses on the skin
  • Nonprescription anti-itch creams or lotions
  • Oatmeal baths
  • Oral antihistamines such as Benadryl
  • 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 compromised 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.
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://www.aafp.org

American Academy of Pediatrics http://www.aap.org

National Immunization Program Centers for Disease Control and Prevention http://www.cdc.gov/vaccines

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.

Berkow R. The Merck Manual of Medical Information. 17th ed. Newy York, NY:Simon and Schuster, Inc; 2000.

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.

Vaccine and Immunizations. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/vaccines/vpd-vac/varicella/default.htm. Accessed July 11, 2008.

Varicella (chickenpox). National Centers for Infectious Diseases website. Available at: http://www.cdc.gov/chickenpox/about/overview.html. Accessed July 11, 2008.

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

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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