Chickenpox is a highly contagious viral infection. It produces a widespread itchy rash. Chickenpox can cause serious complications when contracted by adults, newborns, or people with suppressed immune systems.
Causes
Chickenpox is caused by the varicella zoster virus (VZV). It spreads from person to person via:
Chickenpox is contagious 1-2 days before the rash erupts. However, it is most contagious just after the rash has broken out. It remains contagious until all of the blisters have crusted.
Risk Factors
A risk factor is something that increases your chance of getting a disease or condition.
Risk factors include:
-
Close contact with an infected person (unless you've been vaccinated against or have already had chickenpox)
-
Age: less than 3 years old with peak incidence between 5-9 years old
-
Immune deficient state (leukemia, transplantation)
-
Time of year (late winter, early spring)
Symptoms
Adults have more severe symptoms than children. Symptoms usually break out 10-21 days after contact.
Initial symptoms include:
-
Mild headache
-
Moderate fever
-
General feeling of malaise
Within 1-2 days after the initial symptoms, a rash develops. The rash consists of small, flat, red spots. The spots become raised and form a round, itchy, fluid-filled blister. The blisters develop in clusters, with new clusters forming over 5-6 days.
The rash usually develops on the skin above the waist, including the scalp. The rash may also appear on the eyelids, in the mouth, upper airway, voice box, or on the genitals. The rash typically crusts over by day six or seven and disappears within three weeks.
Diagnosis
The doctor will ask about your symptoms and medical history, and perform a physical exam. Diagnosis is usually made on the basis of age and the rash. Blood and laboratory tests to identify the VZV virus are rarely necessary.
Treatment
In most people, chickenpox is mild and will naturally run its course. In these cases, treatment focuses on relieving the symptoms.
To Reduce Itching
Note: Aspirin should not be given to children with chickenpox because of the increased risk of Reye's syndrome. Check with your doctor before giving aspirin to anyone under 16-18 years of age.
Antibiotics
Since a virus causes chickenpox, antibiotics are not curative. They may be prescribed, however, if the rash becomes infected with bacteria.
Antiviral Medication
There are several antiviral drugs (acyclovir, valacyclovir, famciclovir) which may shorten the course and reduce the severity of infection. They are often used in:
Special Needs
Varicella-zoster immune globulin is often given immediately after exposure to VZV to newborns and people with compromised immune systems.
Prevention
If you have not had chickenpox and have never been vaccinated, avoid contact with anyone who has it.
Several US government agencies and medical groups recommend that all children be routinely vaccinated with an active varicella vaccine at 12-18 months of age and that all susceptible children receive the vaccine before their 13th birthday. Older children and adults should receive two vaccines 4-8 weeks apart if they are not known to have had chickenpox in the past.
It is recommended that the following people not be vaccinated:
-
Those with a history of severe allergic reaction to vaccines
-
Anyone who is immunosuppressed, or receiving immunosuppressive drugs or therapies
-
Pregnant women
RESOURCES:
American Academy of Family Physicians
http://www.aafp.org
American Academy of Pediatrics
http://www.aap.org
National Center for Infectious Diseases, Centers for Disease Control and Prevention
http://www.cdc.gov/ncidod
References:
Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/.
The Merck Manual of Medical Information, 17th ed. Simon and Schuster, Inc.; 2000.
National Centers for Infectious Diseases website. Available at: http://www.cdc.gov/ncidod.
Skull SA, Wang EE. Varicella vaccination: a critical review of the evidence. Arch Dis Child. 2001;85:83-90.
Vazquez M, LaRussa PS, Gershon AA, et al: Effectiveness over time of varicella vaccine. JAMA. 2004;291:851-5.
