3. Noted Points History of Contact Distribution of Rashes Crops
of Rashes in various phases Systemic Symptoms subsided in 3-4
days
4. About the culprit Agent Virus NEUROTROPIC human herpesvirus-
Alpha Herpes Virus virus is enveloped with double-stranded DNA
genomes encode more than 70 proteins
5. What does it do....? Varicella-zoster virus (VZV) causes
primary, latent, and recurrent infections. The primary infection is
manifested as varicella (chickenpox) Recurrent infection known as
Herpes zoster / Shingles
6. Interesting Data USA Annual Case 40 Lakh , Hospitalizations
11000-15000 Deaths- 100-150 Primary Varicella Mortality Rate- 2-3/
100000 cases Lowest among 1-9 yrs of age Infants 4 times risk
Adults 25 times risk of dying Mortality rate is 7-14% in untreated
primary infection in immunocompromised children 50 % in untreated
adults with pneumonia transmission of VZV to susceptible
individuals occurs at a rate of 65-86% contagious 24-48 hr before
the rash is evident and until vesicles are crusted 2 Days before to
7 days/ crusting
7. Contagiousness 1-2 days all lesions are crusted 5 days
8. Pathogenesis VZV is transmitted in by airborne spread -
oropharyngeal secretion through direct contact - fluid of skin
lesions
9. Pathogenesis......Contd
10. Virus is transported in a retrograde manner through sensory
axons dorsal root ganglia throughout the spinal cord virus
establishes latent infection in the neurons and satellite cells
Subsequent reactivation of latent virus herpes zoster
12. Varicella (Chickenpox) Acute Febrile Rash incubation period
is 10 -21 days. Subclinical varicella is rare Prodromal symptoms
Fever malaise anorexia headache mild abdominal pain Systemic
Symptoms resolves within 2-4 days after onset of rash
13. Varicella lesions appear first on the scalp, face, or
trunk. Centripetal Distribution The initial exanthem consists of
intensely pruritic erythematous macules papular stage fluid-filled
vesicles. Clouding and umbilication of the lesions begin in 24-48
hr.
14. simultaneous presence of lesions in various stages of
evolution is characteristic of varicella The number of varicella
lesions 10 to 1,500 Ulcerative lesions involving the mucosa of
oropharynx and vagina
15. vesicular lesions on the eyelids and conjunctivae and
mucosa The exanthem may be much more extensive in children with
skin disorders Hypopigmentation or hyperpigmentation of lesion
sites persists for days to weeks. No Scarring or marks
16. differential diagnosis vesicular rashes caused by other
infectious agents :- enterovirus monkey pox rickettsial pox S.
aureus drug reactions disseminated herpes zoster contact dermatitis
insect bites Small Pox
17. Herpes zoster reactivation of latent VZV. uncommon in
childhood Zoster is not caused by exposure to a patient with
varicella The lifetime risk for herpes zoster for individuals with
a history of varicella is 10-20% 75% of cases occurring after 45 yr
of age. Herpes zoster is very rare in healthy children 97%
effective in preventing severe varicella 85% effective in
preventing all disease after exposure to wild-type VZV.
Breakthrough disease is varicella that occurs in a person
vaccinated >42 days before rash onset and is caused by wild-type
VZV
22. rash occurring < 14 days after vaccination was most
commonly wild-type VZV Rash occurring 14-42 days after vaccination
was due to either Wild-type VZV-------- breakthrough varicella
vaccine strains---------vaccine-associated rash ????????
23. The Breakthrough varicella rashes are atypical
predominantly maculopapular vesicles are seen less commonly illness
is most commonly mild with
