VARICELLA

DEFINITIONVaricella ( Latin), ~ cacar airVaricella (chickenpox) is a highly contagious disease of childhood and occasionaly adulthood, caused by a primary infection with a complex herpes group DNA virus, the varicella-zoster virus.

EPIDEMIOLOGYVaricella is distributed worldwide, but its age specific incidence differs in temperate versus tropical climates and in those population who have received the varicella vaccine.No sex predilection.Childhood > adulthood.

ETIOLOGYCaused by Varicella zoster virus(VZV)Varicella zoster virus is a member of the herpes virus family

PATHOGENESISThe usual route of transmission: airborne droplets, direct contact During primary varicella infection, viremia follows an initial 2 to 4 days of replication in regional lymph nodes

Pathogenesis...In primary viremia: A primary viremia spreads the virus to reticuloendothelial cells in the spleen, liver, and elsewhere In this phase viremia also spreads on upper respiratory tract

PathogenesisIn secondary viremia: A secondary viremia develops after a second cycle of viral replication in the liver, spleen and other organs and seeda the entire body The virus travels to the epidermis by invasion of capillary endhotelial clls approximately 14 to 16 days post exposure

PathogenesisThe VZV subsequently travels from cutaneus and mucosal lesions to invade dorsal root ganglion cells where it remains until reactivation at a later date.

CLINICAL MANIFESTATIONSThe incubation: a range of 11 - 20 days.Primary varicella usually begins as a prodrome of fever, chills, malaise, myalgia, headache, anorexia and backache occur 2-3 days before the eruption.

Clinical manifestationsIn eruptive phase, the rash usually appears first on the face and scalp and spreads rapidly on the trunk, and then the extremities (centripetal distribution)The rash progress rapidly from erythematous macules to papules, vesicles, pustules, and crusts.

Fig.1 Lesions present in Fig.2 Numerous lesions on all stage of development the trunkon face

Fig.3 A thin walled vesicle with clear fluid forms on a red base give the characteristic appearance of a Dewdrop on a rose petal

Fig.4 The vesicle becomes cloudy and depressed in the center (umbilicated)

Fig.5 A crust forms in the center and eventually replaces the remaining portion of the vesicle at the periphery

LABORATORY TESTTzanck smearThe procedure by scrape the base of an early vesicle and stain with hematoxylin-eosin, Giemsa, Papanicolaou, or Paragon multiple stain to demonstrate multinucleated giant cell.Culture virusThe definitive diagnosis of VZV is accomplished by the isolation of virus in cell culture inoculated with vesicle fluid, blood, cerebrospinal fluid and infected tissue.

laboratory testSerologic testThe main value of serologic test is the assesment of the immune status of immunocompromised patients. There are qualitative and quantitative test that measure IgG and IgM antibodies.

DIAGNOSISVaricella can usually be diagnosed readily on the basis of the appearance and evolution of its characteristic rash, especially when there is a history of exposure.

DIFFERENTIAL DIAGNOSESHerpes simplex

The different are on herpes simplex the grouped vesicles on an erythematous base appear. Ussualy located in labial and genital

differential diagnoses2. Contact dermatitis

In contact dermatitis the chief complaint is itch. Contact dermatitis is not associated with the clinical prodrome and commonly involve the extremitas

differential diagnoses3. Variola

The lesions of variola present more commonly in concentration on the face and extremitas at the same rate and same stage of development

differential diagnoses4. Impetigo bullous

Usually occur in face, extremitas, trunk, buttocks, perineum. If bulla ruptur leaving a rim of scale around an erythematous moist base.

differential diagnoses5. Drug eruption

Lesion is generalized and simetrik

THERAPYGeneral : Relieve itching by calamine lotion topical, tepid baths with baking soda or clloidal oatmeal Diet and maintain hydration No activity restiction Discourage scratching to avoid scarring. Trimming the child's fingernails and having the child wear mittens while sleeping may reduce scratching

therapyAntiviral therapy Children : acyclovir, 20 mg/kg four times a day for 5 days Adults : acyclovir, 800mg five times a day for 7 days Immunocompromised patient : foscarnet, 40 mg/kg each 8 hours until healed

therapyAntipyretics Usually used ibuprofen, 200-400mg, or acetaminophen 500 mg third dailyAntihistamin oral Usually used diphenhydramine, 25-50 mg third daily

PREVENTIONActive immunization: give varicella vaccinePassive immunization: give zoster imunnoglobulin

PROGNOSISHealthy children with varicella have excellent prognoses Children with immunocompromised states are at risk for severe disease and death

COMPLICATIONSSecondary bacterial infections CNS complications Pneumonia

SUMMARYVaricella(chickenpox) is a highly contagious disease of childhood and occasionaly adulthood, caused by a primary infection with a complex herpes group DNA virus, the varicella-zoster virus.The rash progress rapidly from erythematous macules to papules, vesicles, pustules, and crusts.

summaryTherapy with antipyretics, antihistamines, and antiviral agents, that usually used is acyclovir.Commonly healthy children with varicella have excellent prognoses

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