By Roopa Rani Halder
Under the guidance of
Pathogenesis And Pathology
• Differential Diagnosis
• Laboratory Findings
Varicella Zoster is a virus which is
responsible for two distinct clinical
entities: Varicella(chicken pox) and
Herpes zoster (Shingles)
This virus is one among the Human
Herpes Viruses and is considered as HHV
A clinical association between varicella
and Herpes zoster has been recognized for
nearly 100 years.
Viral isolates from patients with chicken
pox and herpes zoster produced similar
alterations in tissue culture.
These results suggested that the viruses
were biologically similar.
VZV is a member of
the family Herpes
It has a lipid
double stranded DNA
It is a Primary
usually occurs in
childhood with the
virus entering the
mucosa of the upper
This virus remains
latent in the dorsal
root and cranial nerve
Years later it may be
usually mild in
children but can be
severe in adults.
Lesions are present
on the palate before
the rash appears.
appears on the trunk
on the second day of
Then on the face and finally the limbs are
Macules appear first and within a few hours
the lesions become papular then vesicular
and within 24 hours, pustular.
Whether or not the pustules rupture, they dry
up in a few days to form scabs.
It is a Sporadic disease that results from
reactivation of latent VZV from dorsal root
It occurs at all ages but its incidence is
highest among individuals in the 6th
Herpes zoster is
involved are T3 to
Pathogenesis and pathology
Transmission occurs readily by respiratory route
Localized replication of the virus at an undefined site (Nasopahrynx)
Seeding of the reticulo endothelial system
Development of Viremia
Viremia is reflected in the diffuse and scattered nature of the skin lesions
Vesicle formation and the vesicular fluid becomes cloudy.
The vesicle either rupture and release their fluid or are gradually
The diagnosis of chickenpox is not
Varicella can be confused with
HIV infection with atopic Dermatitis.
More commonly with Rickettsialpox.
Rickettsialpox can be distinguished easily
by detection of the “Herald spot” at the
site of the mite bite and there will be
development of Head ache.
Serologic testing is also useful in
differentiating Rickettsialpox from
Varicella and can confirm it.
The lesions of Small pox are larger than
those of chickenpox.
Laboratory diagnosis is rarely required as
clinical signs are clear-cut.
The most rapid and sensitive means of
diagnosis is examination of vesicle fluid
under electronic microscope which shows
Scrapings of floor of vesicles show
multinucleated giant cells.
Serology is used mainly for
Humans are the only known reservoir for
Chicken pox is highly contagious.
Persons of both sexes and all races are
infected equally often.
The virus is endemic in the population at
Children 5-9 yrs old are most commonly
Chicken pox is transmitted from person to
person by droplet infection and by droplet
Most patients are infected by Face to face
The Portal of entry of the virus is the
Fomites play a significant role in
The virus can cross the placental barrier
and infect the foetus.
More common in
adults and can result
in adult respiratory
1 in 100 cases.
Death may occur.
(VZIG) given within
72 hours of exposure
VZIG is given by IM
injection in a dose of
12.5 units/kg weight
with a repeat dose in
A live attenuated
vaccine is safe and
children between 12-
18 months of age.
adults should be
special emphasis on
high risk groups.
The lesions of
the hood of the
snake and is always
There is a
that Herpes is due to
the Curse of
NAGADEVATA due to
the resemblance of
the pustular lesion
with that of snake.
API text book of medicine.
Textbook of Pathology by HARSHMOHAN
Preventive and Social Medicine by K.PARK
WIKIPEDIA through Internet..