Encyclopedia of Health and Medicine

316 Infectious Diseases
exposure to airborne droplets containing the varicella-zoster
virus. The INCUBATION PERIOD (time
from exposure to illness) is 10 to 21 days.
Symptoms and Diagnostic Path
The first symptoms are general and include FEVER,
HEADACHE, loss of APPETITE, and sometimes NAUSEA
and VOMITING. Within two days the characteristic
pox emerge. These fluid-filled blisters cover the
body and sometimes even occur within the MOUTH,
on the surface and sometimes the inside of the
eyelids, and in the VAGINA. The blisters itch
intensely. In two or three days the fluid within the
blisters oozes out and a crust forms, after which
the itching subsides. However, new batches of
blisters may continue to emerge in clusters for
three to five days after the first outbreak.
Diagnosis is straightforward as the pox are
characteristic and the illness is so highly contagious
that it affects large numbers of people. Many
health-care providers do not want to see people
who are likely to have chickenpox because of the
contagiousness and because treatment is supportive,
not therapeutic. The person is contagious
from two days before the onset of symptoms until
all the pox crust over.
Treatment Options and Outlook
Most people do not require treatment other than
supportive care to improve comfort. Such care
may include
• calamine lotion applied to the blisters to relieve
itching
• oral ANTIHISTAMINE MEDICATION to relieve itching
• acetaminophen or NONSTEROIDAL ANTI-INFLAMMA-
TORY DRUGS (NSAIDS) such as ibuprofen to relieve
headache, fever, and general discomfort
• tepid baths with oatmeal in the water to relieve
itching
Isolation is important until all the pox have
blistered. Schools may require children to remain
home until the crusts are no longer apparent.
Most people recover and are able to return to normal
activities within 7 to10 days. The pox heal
without scarring unless they become infected,
which may happen with excessive scratching.
Do not give aspirin to anyone who has
chickenpox, as doing so creates the risk
for developing REYE’S SYNDROME. Reye’s
syndrome is a serious neurologic condition
that can be fatal.
ANTIVIRAL MEDICATIONS can significantly lessen
the severity and length of illness when taken
within 24 hours of the first pox. However, doctors
typically reserve antiviral medications for people
at risk for severe illness—infants under one year
of age, pregnant women, and people who are
IMMUNOCOMPROMISED—because the normal course
of illness is short and has very low risk for significant
complications. The most common complication
of chickenpox is bacterial infection of the pox
that results from scratching, which introduces
BACTERIA into the blisters. Complications that are
rare though possible include ENCEPHALITIS, PNEUMO-
NIA, and REYE’S SYNDROME.
The varicella-zoster virus remains in the body
after the illness of chickenpox runs its course,
retreating to the NERVE roots where it apparently
enters a stage of dormancy. In 90 percent of people
the virus never re-emerges; however, in about
10 percent of people the virus causes HERPES ZOSTER
(shingles) years to decades after chickenpox.
Risk Factors and Preventive Measures
Exposure to the varicella-zoster virus is the only
risk factor for chickenpox. It is very difficult to
avoid exposure because the MODES OF TRANSMISSION
are multiple. As well, the extremely contagious
nature of the infection coupled with the extended
incubation period means exposure often occurs
before people realize they are ill; outbreaks of
chickenpox are typically widespread. A VACCINE for
chickenpox is part of the routine IMMUNIZATION
schedule for children in the United States. The
vaccine prevents chickenpox in about 85 percent
of people who receive it and significantly reduces
the severity and length of illness in those who
acquire the infection.
See also BLISTER; CHILDHOOD DISEASES; MEASLES;
MUMPS; OCULAR HERPES ZOSTER; PREVENTIVE HEALTH
CARE AND IMMUNIZATION; RUBELLA; SNEEZE/COUGH ETI-
QUETTE.