Infection with the varicella zoster (var-uh-SEH-luh ZOS-ter) virus (VZV) causes the diseases varicella and herpes zoster. Varicella zoster belongs to the herpesvirus family* of viruses.

*herpesvirus: (her-peez-VY-rus) family is a group of viruses that can store themselves permanently in the body. The family includes varicella zoster virus, Epstein-Barr virus, and herpes simplex virus.

KEYWORDS

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Chicken pox

Herpesvirus family

Herpes zoster

Shingles

Varicella zoster virus

What Is Varicella?

This highly contagious disease is characterized by the appearance of crops of red, itchy spots on the skin. The spots progress to blisters and eventually develop crusts and heal. Primary (first-time) infection with varicella causes chicken pox. Usually someone who becomes ill with chicken pox will not have the disease again, because the body’s immune system makes antibodies* that protect against chicken pox in the future.

*antibodies: (AN-tih-bah-deez) are protein molecules produced by the body’s immune system to help fight specific infections caused by microorganisms, such as bacteria and viruses.

After someone has chicken pox, the varicella virus stays inside the person’s body for life. It has the ability to become dormant (inactive) and hide in nerve tissue. After many years, sometimes during a time of emotional or physical stress, varicella can reappear in the form of a disease called shingles, or herpes zoster. (Herpes zoster is not the same as the herpes simplex virus infection that causes cold sores and genital* sores.)

*genital: (JEH-nih-tul) refers to the external sexual organs.

Although the varicella virus causes both chicken pox and shingles, the two have different symptoms and distinct rashes. Shingles usually affects people who are older than 50, although it can develop in people of any age, and its most common sign is a painful single band of red blisters in a small area on one side of the face or body.

How Common Is Varicella?

Chicken pox was once a rite of passage for nearly every child. It used to cause an estimated 4 million cases of illness, 11,000 hospitalizations, and 100 deaths each year in the United States. Today the varicella virus vaccine*, first used in the United States in 1995, has dramatically limited the number of people, especially children, who become infected with varicella. Even with the use of the vaccine, cases of chicken pox are not

*vaccine: (vak-SEEN) is a preparation of killed or weakened germs, or a part of a germ or product it produces, given to prevent or lessen the severity of the disease that can result if a person is exposed to the germ itself. Use of vaccines for this purpose is called immunization.

uncommon. The vaccine may not work in up to 10 to 15 percent of children, and older children and adults who have not had chicken pox or received the vaccine can contract varicella. Shingles is diagnosed in 600,000 to 1 million people in the United States each year.

Chickpea pox?

The word chicken pox may derive from cicer, the Latin word for “chickpea.” A popular ingredient in salads and the base for spreads such as hummus (HUH-mus), chickpeas are round, buff-colored, and a bit larger than green peas. What is the connection to chicken pox? The pox blisters look a bit like chickpeas on the skin.

Is Varicella Contagious?

Chicken pox is highly contagious. Most people who have never had chicken pox or been vaccinated will contract the disease if they come into close contact with someone who has it. Anyone with chicken pox can transmit the virus starting 1 to 2 days before the rash appears and will remain contagious until the pox blisters crust over. Varicella is less contagious when it resurfaces as shingles.

How Is It Spread?

Little bits of moisture, called respiratory droplets, that enter the air when someone coughs or sneezes can spread the varicella virus from one person to another. The fluid inside the pox blisters also can spread the infection. Because shingles blisters carry the varicella virus as well, it is wise for people with shingles to avoid contact with anyone, especially an adult, who has not had chicken pox. It is also best to avoid contact with pregnant women, newborns, and anyone whose immune system is weakened, for example, by HIV/AIDS*, certain kinds of cancers, or having had an organ transplant.

*AIDS ,: or acquired immuno-deficiency (ih-myoo-no-dih-FIH-shen-see) syndrome, is an infection that severely weakens the immune system; it is caused by the human immunodeficiency virus (HIV).

What Are the Signs and Symptoms of Infection?

Chicken pox

The signs of chicken pox usually appear 2 to 3 weeks after exposure to the virus and typically begin with fever, headache, and tiredness. The classic chicken pox rash starts as red spots on the face, chest, back, buttocks, and, less commonly, arms and legs. The spots quickly turn into blisters that break, oozing fluid and then crusting over. Chicken pox spots often pop up in crops, with several spots seeming to appear at once. New batches of blisters usually stop developing after the fourth or fifth day of illness. The rash ranges from mildly to severely itchy, and the number of blisters varies, too—some people have just a few, while others erupt with hundreds of sores.

Shingles

The first symptoms include an intense tingling, burning, or itching that is usually painful and occurs on only one side of the body. A rash of fluid-filled blisters on reddened skin appears next. The rash follows the path of the inflamed nerve tissue and looks like a streak or a band. It can last up to 2 to 3 weeks before healing completely and scabbing over. The pain of shingles usually subsides when the rash disappears, but it may last longer. Other symptoms, such as chills, fever, nausea (NAW-zee-uh), stomach pain, and diarrhea (dye-uh-REE-uh), may occur as well, although they are uncommon.

How Do Doctors Make the Diagnosis?

Doctors usually recognize chicken pox or shingles by their distinctive rashes. Laboratory tests on the fluid in blisters from either disease can help diagnose varicella infection. Blood tests to detect antibodies to the varicella virus can be used to determine whether a person is immune* to chicken pox.

*immune: (ih-MYOON) means resistant to or not susceptible to a disease.

What Is the Treatment for Varicella?

Because varicella is caused by a virus, it does not respond to antibiotics. Doctors advise infected adults and people with weakened immune systems, who are typically at greater risk of experiencing complications of chicken pox (such as pneumonia, nu-MO-nyah, which is inflammation of the lung), to be treated for a few days with specific antiviral medications, such as acyclovir (a-SYE-klo-veer), to control the infection. Preventive treatment also is recommended for people living in the same house with a person who has chicken pox. Children with chicken pox should not be given aspirin for fever, because of the risk of Reye syndrome*. A non-aspirin fever reducer such as acetaminophen (uh-see-teh-MIH-noh-fen) is recommended instead.

*Reye: (RYE) syndrome is a rare condition that involves inflammation of the liver and brain, and sometimes appears after illnesses such as chicken pox or influenza. It has also been associated with taking aspirin during certain viral infections.

In general, the goal of chicken pox treatment is to ease the discomfort caused by itchy blisters. Cool compresses or lukewarm baths in water sprinkled with uncooked oatmeal or baking soda can soothe the skin and relieve itching. Over-the-counter antihistamines* also can help control itching. It is important to trim fingernails short, because scratching blisters can lead to skin infections if the scratching tears the skin. If shingles is recognized soon after its rash first appears it can be treated with oral (by mouth) antiviral medicine. This treatment can shorten the course of the disease and minimize pain.

*antihistamines: (an-tie-HIS-tuh-meens) are drugs used to combat allergic reactions and itching.

How Long Does Infection Last?

Children usually recover from chicken pox within 1 to 2 weeks. Adults may be ill longer. Blisters from shingles typically clear up after 2 to 3 weeks, but nerve pain can linger for weeks or months, sometimes even years.

Are There Complications?

The most common complication of chicken pox is cellulitis (sel-yoo-LYE-tis), an infection of the skin caused by bacteria, such as streptococci (strep-tuh-KAH-kye) and staphylococci (stah-fih-lo-KAH-kye). Skin irritation from repeatedly scratching pox sores allows the bacteria to invade the skin. In some cases, varicella infection can spread to the lungs causing pneumonia. Newborn babies, teens, and adults are more likely to develop this complication. Even in healthy people, chicken pox pneumonia can be dangerous and may be fatal. Adults are also more at risk of other serious but rare complications, including liver and kidney disease and encephalitis (en-seh-fuh-LYE-tis, which is inflammation of the brain). If a woman becomes infected with chicken pox early in her pregnancy, the virus can cause birth defects in the baby. In the final stages of pregnancy, a mother’s chicken pox can cause a life-threatening infection in her baby. Left untreated, a shingles rash anywhere near the eye can spread to the eye. If the cornea* becomes involved, temporary or permanent blindness can result. More serious widespread infection from chicken pox or shingles can occur in anyone with a weakened immune system (such as someone who has HIV/AIDS).

*cornea: (KOR-nee-uh) is the transparent circular layer of cells over the central colored part of the eyeball (the iris) through which light enters the eye.

How Can Varicella Be Prevented?

Since 1995, thousands of children and at-risk adults have been vaccinated against varicella. The American Academy of Pediatrics recommends that all children be vaccinated against chicken pox before 2 years of age. Older children and teens typically receive the vaccine, if they need it, at some point during a regular checkup with a health care provider. The vaccine prevents the disease in about 85 percent of vaccinated people. If people who have been vaccinated become infected with chicken pox, they usually have a milder case of disease. A single dose of varicella zoster immune globulin* (VZIG) can be given intravenously* to protect a person with a weakened immune system who comes into contact with varicella. VZIG contains antibodies to the varicella virus, and if it is given within 3 to 4 days of exposure to the virus, it offers temporary protection.

*immune globulin: (ih-MYOON GLAH-byoo-lin), also called gamma globulin, is the protein material that contains antibodies.

*intravenously: (in-tra-VEE-nus-lee) means given or injected directly through a vein.

See also

Encephalitis

Herpes Simplex Virus Infections

Immune Deficiencies

Mononucleosis, Infectious

Pneumonia

Skin and Soft Tissue Infections

Staphylococcal Infections

Streptococcal Infections

Vaccination (Immunization)

Resources

Organization

American Academy of Pediatrics (AAP), 141 Northwest Point Boulevard, Elk Grove Village, IL 60007. The website of the AAP offers information on varicella and the varicella virus vaccine.

Telephone 847-434-4000 http://www.aap.org

Website

KidsHealth.org. KidsHealth is a website created by the medical experts of the Nemours Foundation and is devoted to issues of children’s health. It contains articles on a variety of health topics, including varicella.

http://www.KidsHealth.org

Complete Human Diseases and Conditions