Dr.Zahraa
Chickenpox
is a very contagious disease caused by the varicella-zoster virus (VZV).
The first symptoms of clinical varicella generally appear after a 10-21 day incubation
period and include fever, malaise and the characteristic itchy rash.
Varicella is generally self-limited and vesicles gradually develop crusts, which disappear
over a period of 7-10 days. Individuals remain contagious until all lesions have crusted
over. The disease is typically mild, but severe complications may arise
It spreads easily from infected people to others who have never had chickenpox or
received the chickenpox vaccine.
VZV is highly transmissible via respiratory droplets or direct contact with characteristic
skin lesions of the infected person.
The rash may first show up on the face, chest, and back then spread to the rest of the
body, including inside the mouth, eyelids, or genital area. It usually takes about one week
for all the blisters to become scabs.
Following infection, the virus remains latent in nerve cells and may be reactivated
causing a secondary infection - herpes zoster “shingles”. This generally occurs in adults
aged >50 years or in the immunocompromised and is associated with a painful rash that
may result in permanent nerve damage.
DIAGNOSIS
• Clinical
•
Blood
– At first leucopenia for first 72 hours; followed by a lymphocytosis.
– VZV immunoglobulin G (IgG) antibodies can be
detected (4-fold rise in IgG antibodies) is also confirmatory of acute infection.
• CSF: increase in protein in the cerebrospinal fluid; glucose concentration being
normal.
EPIDEMIOLOGY
It occurs allover the world and may effect almost everybody, but children under ten
years are most susceptible.
Immunity after an attack is long lived, may be for life.
Chickenpox is a relatively mild disease in healthy children but may be life threatening in
immunosuppressed patients, neonates.
The epidemiology of chickenpox appears to be changing: There has been an unexplained
upward shift in the age distribution of cases over the last 20 years.
TREATMENT
Oral therapy with acyclovir given as four doses per day for five days is the drug of
choice.
In healthy adults, acyclovir 800 mg is given five times a day orally for five days.
Immunocompromised patients benefit from both symptomatic and antiviral therapy.
Oral acyclovir administered late in the incubation period may modify subsequent
varicella in the normal child.
People who may have more severe symptoms and may be at high risk for complications
include
Infants
Pregnant women
People with HIV/AIDS or cancer
Patients who have had transplants, and
People on chemotherapy, immunosuppressive medications, or long-term use of steroids.
Immunocompromised persons who get varicella are at risk of developing visceral
dissemination (VZV infection of internal organs) leading to pneumonia, hepatitis,
encephalitis, and disseminated intravascular coagulopathy.
They can have atypical varicella rash with more lesions, and they can be sick longer
than immunocompetent persons who get varicella. The lesions may continue to erupt for
as long as 10 days, may appear on the palms and soles, and may be hemorrhagic.
Prevention
•
The best way to prevent chickenpox is to get the chickenpox vaccine. Children,
adolescents, and adults should have two doses of chickenpox vaccine.
•
Chickenpox vaccine is very safe and effective at preventing the disease.
Most people who get the vaccine will not get chickenpox.
Passive Immunization
Varicella-zoster immune globulin (VZIG) post exposure prophylaxis is recommended for
Immunocompromised children, pregnant women, and newborns exposed to maternal
varicella.
Close contact between a susceptible high-risk patient and a patient with herpes zoster
Varicella-Zoster immunoglobulin (VZIG) given by intramuscular route within 72 hours of
exposure(effective in preventing the disease or modifying it).
Active Immunization
Vaccine given to normal children within three to five days exposure is effective in
preventing or modifying varicella.
Varicella vaccine is now recommended for postexposure use, for outbreak control.
Live virus vaccine is recommended for routine administration in children at 12 to 18
months of age (single vaccine dose)
Adolescents and adults require two vaccine doses, a minimum of four weeks apart.
Tetravalent combined measles, mumps, rubella, and varicella vaccine (MMRV).
CDC recommends two doses of chickenpox vaccine for children, adolescents, and adults.
Two doses of the vaccine are about 98% effective at preventing chickenpox.
Children should receive two doses of the vaccine—the first dose at 12 through 15 months
old and a second dose at 4 through 6 years old.
adolescents and adults require two vaccine doses, a minimum of four weeks apart.
If a vaccinated person does get chickenpox, it is usually mild—with fewer blisters and
mild or no fever. The chickenpox vaccine prevents almost all cases of severe disease.
Contraindications
Children with cell-mediated immune deficiencies.
pregnancy (because of a theoretical risk to the fetus; pregnancy should be avoided for 4
weeks following vaccination ).
History of anaphylactic reactions to any component of the vaccine.
Immunosuppression.