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Salem Health: Infectious Diseases & Conditions, 2nd Edition

Chickenpox

by Rick Alan

Category: Diseases and conditions

Anatomy or system affected: All

Also known as: Varicella

Definition

Chickenpox is a highly contagious viral infection that produces a widespread itchy rash and crusting.

Causes

Chickenpox is caused by the varicella zoster virus (VZV), which can spread from person to person through airborne droplets of moisture containing VZV and through direct contact with fluid from a chickenpox rash. The virus is most contagious for one to two days before the rash erupts and during the first day or so after the rash has broken out. The infection remains contagious until all the blisters have crusted.

Chickenpox tends to be a childhood illness which can later reemerge as shingles (herpes zoster). Photo by Øyvind Holmstad via Wikimedia Commons

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Because of an extensive vaccination program, the incidence of chickenpox has declined greatly in the United States. The majority of cases (about 90 percent) occur in infants, children, and adolescents age fourteen years and younger. The incidence among adults age twenty years or older is low (approximately 5 percent of cases). When contracted during childhood, chickenpox is usually not serious. Serious complications are more common when the infection occurs in adolescents, adults, newborns, or people with suppressed immune systems. These complications, which usually occur in adults or older children, can include pneumonia; liver or kidney inflammation; central nervous system complications, including aseptic meningitis, acute cerebellar ataxia (most common), encephalitis, transverse myelitis, Guillain-Barré syndrome, and Reye’s syndrome (generally only in children and teenagers); bleeding problems because of low platelet counts; and bacterial infections from group A Streptococcus and Staphylococcus aureus, which lead to infections in the skin (cellulitis) and to toxic shock syndrome, bacteremia, arteritis, gangrene, osteomyelitis, and pericarditis.

If a susceptible woman gets chickenpox while pregnant, injury to the fetus may occasionally result. Some associated birth disorders include poor growth of arms or legs, skin scarring, a small head, and perhaps mental disability (retardation) or other abnormalities of the nervous system.

Another complication of chickenpox is shingles. This can occur years after the chickenpox infection.

Risk Factors

If a person is not immune to chickenpox, factors that will increase the risk of contracting the disease include coming in direct contact with someone infected with chickenpox and sharing eating utensils or other personal items with someone who has chickenpox. Some populations are at a higher risk for chickenpox, including persons of any age who have neither had chickenpox in the past nor been immunized against chickenpox (with varicella vaccine); newborns, especially those born prematurely, less than one month old, or whose mothers had never contracted chickenpox before pregnancy; people with a weakened immune system (from chemotherapy, human immunodeficiency virus [HIV] infection, acquired immunodeficiency syndrome [AIDS], or congenital or acquired immunodeficiencies); people with cancer; pregnant women; people who are taking immunosuppressant drugs (such as high-dose steroids); people who are moderately or severely ill and are not yet fully recovered; and people who have certain disorders affecting the blood, bone marrow, or the lymphatic system.

If one is not immune to chickenpox, traveling abroad can increase the risk of contracting chickenpox. The disease is much more prevalent outside the United States because of much lower rates of vaccination.

Symptoms

Symptoms usually occur ten to twenty-one days after contact with the chickenpox virus. Initial symptoms include headache, fever, a general feeling of malaise, and loss of appetite. Within one to two days after the initial symptoms, a rash develops. Characteristics of the rash include, initially, small, flat, red spots. The spots become raised and form clusters of round, itchy, fluid-filled blisters on a red base. The blisters develop in clusters, with new clusters forming in five or six days.

Once the rash develops, a variety of spots are almost always visible. These spots include flat red areas, blisters with clear fluid, blisters with cloudy fluid, and open blisters. This variety helps doctors determine that the rash is from chickenpox.

Talking to a Healthcare Provider About Chickenpox

Specific Questions to Ask About Developing Chickenpox

Should I be tested to see if I have immunity to chickenpox?

After possible exposure to chickenpox, what is the incubation period?

How long is someone contagious after they have contracted the disease?

How do I know if my immune system is suppressed?

Specific Questions About Treatment Options

Should I be vaccinated against chickenpox?

At what age can my child be vaccinated against chickenpox?

What over-the-counter drugs can I give my child for relief of itching, pain, and fever?

If I’m at risk for severe disease, what medications can I take to help prevent complications?

What are the benefits and side effects of these medications?

Will these medications interact with other medications, over-the-counter products, or dietary and herbal supplements?

At what point should I seek medical care for possible complications of chickenpox?

How can I best keep the blisters from scarring?

Specific Questions About Lifestyle Changes

I’m pregnant (or planning on getting pregnant in the near future). Are there any special precautions I should take?

What precautions should I take if I’m traveling abroad?

How long do I need to keep my child isolated after he (or she) has been infected with chickenpox?

Specific Questions About Outlook

Are there any possible long-term complications from chickenpox?

The rash usually develops on the skin above the waist, including the scalp. Exposed areas are often most significantly affected. The rash may sometimes appear on the inside of the eyelids and in the mouth, nose, throat, upper airway, larynx (voice box), rectum, or vagina. In healthy children, the rash usually crusts over by day six or seven. The crusts disappear within three weeks, usually without scarring. Adults and immunocompromised persons may have more severe cases of chickenpox that last longer than the norm.

Screening and Diagnosis

Screening tests include blood and laboratory tests, including a skin smear to infer the presence of chickenpox virus by staining, a skin smear to detect chickenpox viral proteins using immunofluorescence, and a blood test to detect the presence and measure the amounts of antibodies to chickenpox virus.

Treatment and Therapy

In most children, chickenpox is mild and will naturally run its course and disappear on its own. In these cases, treatment focuses on relieving the symptoms through medications. There are no surgical options, however.

Prevention and Outcomes

To avoid getting chickenpox, one should avoid contact with people who have the infection and should avoid sharing personal items with infected persons. Also, one should get a chickenpox vaccination if he or she has not already done so. The National Immunization Program of the Centers for Disease Control and Prevention (CDC) recommends that those persons who are unsure if they have had chickenpox or if they have been vaccinated should consult a doctor about getting a blood test to determine immunity. A negative test result means the person is not immune.

People who have had chickenpox are unlikely to get it a second time. However, because the chickenpox virus remains in the body (by hiding in spinal nerve cells), some adults will develop a localized recurrence of chickenpox known as herpes zoster or shingles.

The CDC and the American Academy of Family Physicians recommend that all healthy people (especially adults and infants age one year and older) who have not had chickenpox receive the vaccination. However, those who should not receive the varicella vaccine include persons who are severely allergic to neomycin or gelatin; are recovering from a recent illness and not yet fully recovered; are recent recipients of certain kinds of blood or plasma transfusions (in the preceding five months); are immunocompromised because of HIV, immunosuppression (such as after a kidney transplant), or a congenital condition; are living with a person who is immunocompromised and who cannot leave the living arrangement for three weeks following immunization in case the newly immunized person develops a rash; are affected by disorders of the blood, bone marrow, or the lymphatic system; are pregnant or might become pregnant within the next month (according to the CDC, women should avoid becoming pregnant for one month following varicella vaccination); are taking relatively large doses of corticosteroids or are on other immunosuppressant drugs; or are currently taking aspirin. Because of the association between aspirin and Reye’s syndrome in children and teens with chickenpox, the resumption of aspirin should ideally be delayed for six weeks after a chickenpox vaccination. Where this is not feasible, one should carefully discuss risks and benefits with a doctor.

Persons who have been exposed to VZV and who cannot receive the varicella vaccine might be able to receive immunoglobulin instead. Immunoglobulin is a blood product that contains antibodies to the chickenpox virus. As a form of prevention, immunoglobulin is given by injection immediately after exposure to VZV (within ninety-six hours) and is only given, most usually, to people who are at very high risk for severe complications from the disease. These persons include adults (including pregnant women), newborns whose mothers have chickenpox, and people who are immunosuppressed or very ill.

Further Reading

1 

Crossley, Kent B., Kimberly K. Jefferson, and Gordon L. Archer, eds. Staphylococci in Human Disease. Hoboken, N.J.: John Wiley & Sons, 2009.

2 

Daley, A. J., S. Thorpe, and S. M. Garland. “Varicella and the Pregnant Woman: Prevention and Management.” Australian and New Zealand Journal of Obstetrics and Gynaecology 48 (2008): 26-33.

3 

Galil, K., et al. “Hospitalizations for Varicella in the United States, 1988 to 1999.” Pediatric Infectious Disease Journal 10 (2002): 931-935.

4 

Levin, M. J. “Varicella Vaccination of Immunocompromised Children.” Journal of Infectious Diseases 197 (2008): S200-206.

5 

McCarter-Spaulding, D. E. “Varicella Infection in Pregnancy.” Journal of Obstetric, Gynecologic, and Neonatal Nursing 30, no. 6 (2001): 667-673.

6 

Memish, Z. A., et al. “The Cost-Saving Potential of Prevaccination Antibody Tests When Implementing a Mass Immunization Program.” Military Medicine 166, no. 1 (2001): 11-13.

7 

Niederhauser, V. P. “Varicella: The Vaccine and the Public Health Debate.” Nurse Practitioner 3 (1999): 74-76, 79, 83-84.

8 

Long, Sarah S., Larry K. Pickering, and Charles G. Prober, eds. Principles and Practice of Pediatric Infectious Diseases. 3d ed. Philadelphia: Churchill Livingstone/Elsevier, 2008.

9 

Ratner, A. J. “Varicella-Related Hospitalizations in the Vaccine Era.” Pediatric Infectious Disease Journal 10 (2002): 927-931.

10 

Ronan, K., and M. R. Wallace. “The Utility of Serologic Testing for Varicella in an Adolescent Population.” Vaccine 19, no. 32 (2001): 4700-4702.

11 

Weller, T. H. “Varicella: Historical Perspective and Clinical Overview.” Journal of Infectious Diseases 174 (1996): S306-309.

Web Sites of Interest

About Kids Health

http://www.aboutkidshealth.ca

American Academy of Family Physicians

http://familydoctor.org

Centers for Disease Control and Prevention

http://www.cdc.gov

National Immunization Program

http://www.cdc.gov/nip

National Shingles Foundation

http://www.vzvfoundation.org

See also: Airborne illness and disease; Herpes zoster vaccine; Children and infectious disease; Contagious diseases; Herpes zoster infection Herpesviridae; Herpesvirus infections; Immunity; Immunization; Postherpetic neuralgia; Pregnancy and infectious disease; Schools and infectious disease; Shingles; Skin infections; Vaccines: Types; Viral infections.

Citation Types

Type
Format
MLA 9th
Alan, Rick. "Chickenpox." Salem Health: Infectious Diseases & Conditions, 2nd Edition, edited by H. Bradford Hawley, Salem Press, 2020. Salem Online, online.salempress.com/articleDetails.do?articleName=Infect2e_0117.
APA 7th
Alan, R. (2020). Chickenpox. In H. B. Hawley (Ed.), Salem Health: Infectious Diseases & Conditions, 2nd Edition. Salem Press. online.salempress.com.
CMOS 17th
Alan, Rick. "Chickenpox." Edited by H. Bradford Hawley. Salem Health: Infectious Diseases & Conditions, 2nd Edition. Hackensack: Salem Press, 2020. Accessed September 16, 2025. online.salempress.com.