Chickenpox, the common name for varicella, is an acute, highly contagious infection that can occur at any age but is most common in children ages 5 to 9. Congenital varicella may affect infants whose mothers had acute infections in their first or early second trimester. Neonatal infection is rare, probably because of transient maternal immunity.
Chickenpox occurs worldwide and is endemic in large cities. Outbreaks occur sporadically and with varying severity, usually in areas with large groups of susceptible children. It affects all races and both sexes equally. Seasonal distribution varies; in temperate areas, incidence is higher during late winter and spring.
Most children recover completely. However, potentially fatal complications may affect children receiving corticosteroids, antimetabolites, or other immunosuppressants, and those with leukemia, other malignant diseases, or immunodeficiency disorders. Congenital and adult varicella also may have severe effects.
The varicella zoster virus is thought to become latent until the sixth decade of life, or later, when herpes zoster may present as a dermatomal vesicllia rash (shingles) that usually causes severe pain.
Chickenpox is caused by the varicella zoster virus. It spreads from person to person via: Airborne droplets of moisture containing the VZV virus. Direct contact with fluid from a chickenpox rash
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.
Symptoms and Signs
The signs and symptoms of shingles may include:
Although diagnosis usually doesn't require laboratory tests, the virus can be isolated from vesicular fluid within the first 3 to 4 days of the rash. Giemsa stain distinguishes the varicella-zoster virus from the vaccinia-variola virus. Serum samples contain antibodies 7 days after onset of symptoms. Serologic testing is useful in differentiating rickettsial pox from varicella.
Chickenpox calls for strict isolation until all the vescles have crusted over. Children can go back to school if just a few scabs remain; at this stage, chickenpox is no longer contagious. Congenital chickenpox requires no isolation.
Treatment consists of local or systemic antipruritics, such as calamine lotion, diphenhydramine or another antihistamine, or cool sponge baths with baking soda.
The patient doesn't need antibiotics unless bacterial infection develops. Salicylates are contraindicated because of their link with Reye's syndrome. Instead, the patient can receive acetaminophen as an analgesic and antipyretic. Antiviral drugs and corticosteroids aren't used to treat immunocompetent patients.
Immunosuppressed patients may need special treatment. I.V. acyclovir is recommended for these individuals for both chickenpox and herpes zoster. It reduces visceral complications but has no effect on the healing of lesions. When given up to 72 hours after exposure to chickenpox, varicella-zoster immune globulin may provide passive immunity.
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:
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