chickenpox (varicella)

ChickenpoxChickenpox(Varicella)(Varicella)

Dr. Harivansh ChopraDr. Harivansh ChopraDCH, MDDCH, MD

PROFESSORPROFESSORDepartment of Community Medicine,Department of Community Medicine,LLRM Medical College, Meerut.LLRM Medical College, Meerut. [email protected]@gmail.com

Dr. Harivansh ChopraDr. Harivansh Chopra

ObjectivesObjectives

1.1. To study the epidemiology of Chickenpox.To study the epidemiology of Chickenpox.

2.2. To study the differential diagnosis and To study the differential diagnosis and treatment of the disease.treatment of the disease.

3.3. To study the prevention of Chickenpox.To study the prevention of Chickenpox.


Chickenpox (Varicella)Chickenpox (Varicella)

1.1. It is characterised by It is characterised by vesicular rash that vesicular rash that may be accompanied may be accompanied by fever and malaise. by fever and malaise.

2.2. It is worldwide in It is worldwide in distribution and occurs distribution and occurs in both epidemic and in both epidemic and endemic forms. endemic forms.


AgentAgent

1.1. The causative agent of chickenpox, V-Z virus The causative agent of chickenpox, V-Z virus is also called “Human (alpha) herpes virus is also called “Human (alpha) herpes virus 3”.3”.


AgentAgent

2.2. Varicella-zoster virus (VZV) Varicella-zoster virus (VZV) causes primary, latent, and causes primary, latent, and recurrent infections.recurrent infections.

3.3. The primary infection is The primary infection is manifested as Varicella manifested as Varicella (chickenpox) and results in (chickenpox) and results in establishment of a lifelong establishment of a lifelong latent infection of sensory latent infection of sensory ganglion neurons.ganglion neurons.

Microscopic view of sensoryganglion neurons: Common

site of latent infection by Varicella


AgentAgent

4.4. Reactivation of the Reactivation of the latent infection latent infection causes Herpes Zoster causes Herpes Zoster (shingles). (shingles).


Herpes ZosterHerpes Zoster

1.1. Reactivation of Varicella Reactivation of Varicella zoster virus.zoster virus.

2.2. Associated with:Associated with:

1.1. Aging.Aging.

2.2. Immunosuppression.Immunosuppression.

3.3. Intrauterine exposure.Intrauterine exposure.

4.4. Varicella at < 18 months of Varicella at < 18 months of age.age.


Source of InfectionSource of Infection

1.1. Usually a case of chickenpox. Usually a case of chickenpox.

2.2. The virus occurs in the The virus occurs in the oropharyngeal secretions oropharyngeal secretions and lesions of skin and and lesions of skin and mucosa.mucosa.

3.3. Rarely the source of infection Rarely the source of infection may be a patient with Herpes may be a patient with Herpes Zoster.Zoster.

Chickenpox transmission occurs mainly from the oropharyngeal

secretions of a case.


InfectivityInfectivity

The period of The period of communicability of communicability of patients with Varicella is patients with Varicella is estimated to range from 1 estimated to range from 1 to 2 days before the to 2 days before the appearance of rash, and 4 appearance of rash, and 4 to 5 days thereafter. to 5 days thereafter.


Incubation periodIncubation period

Usually 14 to 16 days, Usually 14 to 16 days, although extremes as although extremes as wide as 7 to 21 days wide as 7 to 21 days have been reported.have been reported.


AgeAge

1.1. Chickenpox occurs Chickenpox occurs primarily among primarily among children under 10 children under 10 years of age.years of age.


ImmunityImmunity

1.1. One attack gives One attack gives durable immunity. durable immunity. Second attacks are Second attacks are rare.rare.

2.2. The acquisition of The acquisition of maternal antibody maternal antibody protects the infant protects the infant during the first few during the first few months of life. months of life. Hemorrhagic Varicella in infant :

One attack of Varicellagives durable immunity.


ImmunityImmunity

3.3. The IgG antibodies persist for The IgG antibodies persist for life and their presence is life and their presence is correlated with protection correlated with protection against Varicella.against Varicella.

4.4. The cell- mediated immunity The cell- mediated immunity appears to be important in appears to be important in recovery from V -Z infections recovery from V -Z infections and in protection against the and in protection against the reactivation of latent V-Z reactivation of latent V-Z virus.virus.

Structure of an IgG antibody:Antibody against Varicella is

protective


Pregnancy & VaricellaPregnancy & Varicella

Infection during Infection during pregnancy presents a pregnancy presents a risk for the fetus and the risk for the fetus and the neonate.neonate.


Environmental FactorsEnvironmental Factors

1.1. Chickenpox shows a Chickenpox shows a seasonal trend in India, the seasonal trend in India, the disease occurring mostly disease occurring mostly during the first six months during the first six months of the year. of the year.

2.2. Overcrowding favours its Overcrowding favours its transmission. transmission.


TransmissionTransmission

1.1. Chickenpox is transmitted Chickenpox is transmitted from person to person by from person to person by droplet infection and by droplet infection and by droplet nuclei.droplet nuclei.

2.2. Most patients are infected Most patients are infected by "face-to-face" (personal) by "face-to-face" (personal) contact. contact.



3.3. The portal of entry of The portal of entry of the virus is the the virus is the respiratory tract.respiratory tract.

4.4. Since the virus is Since the virus is extremely labile, it is extremely labile, it is unlikely that fomites unlikely that fomites play a significant role play a significant role in its transmission.in its transmission.

Main portal of chickenpoxtransmission is respiratory


SECONDARY ATTACK RATE

90%



5.5. Contact infection Contact infection undoubtedly plays a role undoubtedly plays a role when an individual with when an individual with Herpes Zoster is an index Herpes Zoster is an index case. case.

6.6. The virus can cross the The virus can cross the placental barrier and infect placental barrier and infect the foetus, a condition the foetus, a condition known as Congenital known as Congenital Varicella.Varicella.

Mother-to-Child transmission of Varicella can cause Congenital Varicella


Congenital Varicella SyndromeCongenital Varicella Syndrome

1.1. Results from Results from maternal infection maternal infection during pregnancy.during pregnancy.

2.2. Period of risk may Period of risk may extend through first extend through first 20 weeks of 20 weeks of pregnancy.pregnancy.

3.3. Risk appears to be Risk appears to be small (< 2%).small (< 2%).

MRI scan of foetus in-utero:Risk of transmission of Varicellaextends through first 20 weeks.


Congenital Varicella Syndrome – Congenital Varicella Syndrome – FeaturesFeatures

1.1. Damage to Sensory Damage to Sensory Nerves :Nerves :

1.1. Cicatricial skin Cicatricial skin lesions.lesions.

2.2. Hypopigmentation.Hypopigmentation.

This neonate suffering fromCongenital Varicella died at 6th day: Typical skin lesions

seen at autopsied body



2.2. Damage to Optic Stalk Damage to Optic Stalk and Lens Vesicle :and Lens Vesicle :

1.1. Microphthalmia. Microphthalmia.

2.2. Cataracts.Cataracts.

3.3. Chorioretinitis. Chorioretinitis.

4.4. Optic atrophy.Optic atrophy.Fetus with Congenital Varicella at autopsy (26 weeks). Note the

collapsed cranium, disproportionate Necrosis of the ocular globes

and flattened midface.



3.3. Damage to Damage to Brain/Encephalitis : Brain/Encephalitis :

1.1. Microcephaly. Microcephaly.

2.2. Hydrocephaly. Hydrocephaly.

3.3. Calcifications.Calcifications.

4.4. Aplasia of brain. Aplasia of brain. Brain sonograph of a fetus with Congenital Varicella at 18 weeks.

Note the appearance of the falx cerebri, choroid plexus and cerebral hemispheres.



5.5. Damage to Cervical or Damage to Cervical or Lumbosacral Cord : Lumbosacral Cord :

1.1. Hypoplasia of an Hypoplasia of an extremity. extremity.

2.2. Motor and sensory Motor and sensory deficits.deficits.

3.3. Absent deep tendon Absent deep tendon reflexes. reflexes.

Neonate with Congenital Varicella:Note hypoplasia of lower extremity.

The extremity had sensory andmotor deficits.



5.5. Damage to Cervical or Damage to Cervical or Lumbosacral Cord : Lumbosacral Cord :

4.4. Anisocoria.Anisocoria.

5.5. Horner syndrome. Horner syndrome.

6.6. Anal/urinary sphincter Anal/urinary sphincter dysfunction. dysfunction.

Pictoral representation of anisocoria.(this case is not Congenital Varicella)

Pictoral representation of Horner Syn.(this case is not Congenital Varicella)


Anisocoria: Both pupils are usually of equal size. If they are not, that is termed anisocoria (from "a-", not + "iso", equal + "kore", pupil = not equal pupils)


The clinical features of Horner's syndrome can be remembered using the mnemonic, "HornyPAMELa" for Ptosis, Anhidrosis, Miosis, Enophthalmos and Loss of ciliospinal reflex.


Clinical features of Chickenpox – Clinical features of Chickenpox –

The clinical course of chickenpox may be The clinical course of chickenpox may be divided into two stages:divided into two stages:

(A)(A)Pre-eruptive Stage.Pre-eruptive Stage.

(B) Eruptive Stage. (B) Eruptive Stage.


Pre-Eruptive StagePre-Eruptive Stage

1.1. Onset is sudden with Onset is sudden with mild or moderate mild or moderate fever, pain in the back, fever, pain in the back, shivering and malaise.shivering and malaise.

2.2. This stage is very This stage is very brief, lasting about 24 brief, lasting about 24 hours.hours.

Pre-eruptive phase in Varicellais very brief – characterised by Fever, pain in back, shivering,

and malaise


Pre-Eruptive StagePre-Eruptive Stage

3.3. In adults, the prodromal In adults, the prodromal illness is usually more illness is usually more severe and may last for severe and may last for 2-3 days before the rash 2-3 days before the rash comes out.comes out.


Eruptive PhaseEruptive Phase

1.1. In children the rash is often the first sign. In children the rash is often the first sign.

2.2. It comes on the day the fever starts. It comes on the day the fever starts.


Eruptive Phase – Eruptive Phase – Fever Fever

The fever does not run The fever does not run high but shows high but shows exacerbations with each exacerbations with each fresh crop of eruption.fresh crop of eruption.


1.1. The rash is symmetrical.The rash is symmetrical.

2.2. It first appears on the It first appears on the trunk where it is trunk where it is abundant, and then comes abundant, and then comes on the face, arms and legs on the face, arms and legs where it is less abundant.where it is less abundant.

Eruptive Phase – Rash Eruptive Phase – Rash


3.3. Mucosal surfaces (e.g. Mucosal surfaces (e.g. buccal, & pharyngeal buccal, & pharyngeal mucosa) are generally mucosa) are generally involved.involved.




4.4. Axilla may be Axilla may be affected, but palms affected, but palms and soles are usually and soles are usually not affected.not affected.

5.5. The density of the The density of the eruption diminishes eruption diminishes centrifugally.centrifugally.


Eruptive Phase – Evolution of Eruptive Phase – Evolution of Rash Rash

1.1. The rash advances quickly through the stages of The rash advances quickly through the stages of macule, papule, vesicle and scab.macule, papule, vesicle and scab.

2.2. In fact, the first to attract attention are often the In fact, the first to attract attention are often the vesicles filled with clear fluid and looking like vesicles filled with clear fluid and looking like "dew-drops" on the skin. "dew-drops" on the skin.


Eruptive Phase – Eruptive Phase – Evolution of Rash Evolution of Rash

3.3. They are superficial, They are superficial, with easily ruptured with easily ruptured walls and surrounded walls and surrounded by an area of by an area of inflammation.inflammation.

4.4. Usually they are not Usually they are not umbilicated.umbilicated.

Superficial vesicles

Unilocular Vesicles;Dew-drop like.

Inflammation around vesicles


Eruptive Phase – Eruptive Phase – Evolution of Rash Evolution of Rash

5.5. The vesicles may form crusts without going through the The vesicles may form crusts without going through the pustular stage.pustular stage.

6.6. Many of the lesions may abort. Many of the lesions may abort.

7.7. Scabbing begins 4 to 7 days after the appearance of Scabbing begins 4 to 7 days after the appearance of rash.rash.


A characteristic feature of A characteristic feature of the rash in chickenpox is its the rash in chickenpox is its “Pleomorphism”, i.e. all “Pleomorphism”, i.e. all stages of the rash (Papules, stages of the rash (Papules, Vesicles and Crusts) may be Vesicles and Crusts) may be seen simultaneously at one seen simultaneously at one time, in the same area. time, in the same area.

Eruptive Phase – Eruptive Phase – Pleomorphic Rash Pleomorphic Rash


Varicella – Differential DiagnosisVaricella – Differential Diagnosis

1.1. Herpes simplex.Herpes simplex.

2. Enterovirus.2. Enterovirus.

3.3. Staphylococcus aureus. Staphylococcus aureus. (Bullous impetigo)(Bullous impetigo)



4.4. Drug reactions.Drug reactions.

5. Contact dermatitis.5. Contact dermatitis.

6.6. Insect bites.Insect bites.



Severe Varicella was the most common Severe Varicella was the most common illness confused with smallpox before the illness confused with smallpox before the eradication of this disease. eradication of this disease.


Differences between Differences between Smallpox and ChickenpoxSmallpox and Chickenpox

During the first day or two of rash it may be impossible, from the rash alone, to differentiate smallpox from chickenpox.


On day 3, the rash associated with each of the diseases continues to look very similar.



By day 5, all of the smallpox lesions are at the same stage of development.

However, the patient with chickenpox shows several different stages of rash – There are papules, vesicles and pustules present.



The smallpox lesions are large : 5 – 10 mm in size; firm and deeply embedded in skin.

Most of the chickenpox lesions are smaller : 1 – 5 mm in size; lesions are much superficial.



By day 7, no formation of scabs in smallpox lesions.

Most of chickenpox lesions have already formed scabs, and some scabs, in fact, have already seperated.



By day 10, smallpox scabs have just begun to form.

In chickenpox, most of the scabs have fallen off by day 10. (In chickenpox, scabs begin to form as early as day 3 or 4, and fall off by day 14).



Chickenpox – many pocks on back but very few on arms or hands.

Smallpox – pocks are more dense on the arms and legs than on the trunk.



In chickenpox there may be few or no lesions on the palms of the hands.

In smallpox, pocks are usually present on palms of hands.



In smallpox, many lesions are present on the soles of feet.

In chickenpox, patient may have very few or no lesions on soles of feet.



In smallpox, death occured 1 in 10 cases.

In chickenpox, death is very uncommon.



Varicella ComplicationsVaricella Complications

1.1. Secondary bacterial Secondary bacterial infection of lesions.infection of lesions.

2.2. Cellulitis, Cellulitis, Lymphadenitis, and Lymphadenitis, and Subcutaneous abscess.Subcutaneous abscess.

3.3. Varicella gangrenosa Varicella gangrenosa from from S.pyogenes S.pyogenes – a – a life-threatening life-threatening infection.infection.



4.4. Bacteremia causing Bacteremia causing pneumonia, arthritis, pneumonia, arthritis, and osteomyelitis. and osteomyelitis.

5.5. CNS manifestations – CNS manifestations – Encephalitis & Encephalitis & Cerebellar ataxia.Cerebellar ataxia.

6.6. Varicella hepatitis.Varicella hepatitis.



7.7. Acute thrombocytopenia, accompanied by petechiae, Acute thrombocytopenia, accompanied by petechiae, purpura, hemorrhagic vesicles, hematuria, and GI bleeding.purpura, hemorrhagic vesicles, hematuria, and GI bleeding.

8.8. Nephritis, Nephrotic syndrome, and HUS.Nephritis, Nephrotic syndrome, and HUS.


Groups at Increased Risk of Groups at Increased Risk of Complications of VaricellaComplications of Varicella

1.1. Healthy adolescents & adults.Healthy adolescents & adults.

2.2. Immunocompromised persons.Immunocompromised persons.

3.3. Pregnant women.Pregnant women.


Groups at Increased Risk of Groups at Increased Risk of Complications of VaricellaComplications of Varicella

4.4. Newborns of mothers Newborns of mothers with rash onset within 5 with rash onset within 5 days before delivery to days before delivery to 48 hours after delivery.48 hours after delivery.

5.5. Children with Children with malignancy if malignancy if chemotherapy was chemotherapy was given during the I.P.given during the I.P.


Laboratory diagnosisLaboratory diagnosis

1.1. Examination of vesicle Examination of vesicle fluid under the fluid under the electron microscope, electron microscope, which shows round which shows round particles (brick-particles (brick-shaped in smallpox) shaped in smallpox) and may be used for and may be used for cultivation of the cultivation of the virus.virus.


Laboratory diagnosisLaboratory diagnosis

2.2. Scrapings of floor of Scrapings of floor of vesicles show vesicles show multinucleated giant cells multinucleated giant cells coloured by Giemsa stain coloured by Giemsa stain (not in smallpox). (not in smallpox).

3.3. Serology is used mainly Serology is used mainly for epidemiological for epidemiological surveyssurveys..


1.1. Oral therapy with Acyclovir – Oral therapy with Acyclovir – 20 mg/kg/dose 20 mg/kg/dose maximum: 800 mg/dose maximum: 800 mg/dose 4 doses per day X 5 days should 4 doses per day X 5 days should be used to treat uncomplicated Varicella be used to treat uncomplicated Varicella

Treatment of uncomplicated Treatment of uncomplicated VaricellaVaricella


2.2. Acyclovir guanine – 500 mg/mAcyclovir guanine – 500 mg/m22 8 hourly 8 hourly I.V. X 7 days.I.V. X 7 days.

Given within 72 hrs. prevents progressive Given within 72 hrs. prevents progressive Varicella and visceral dissemination in Varicella and visceral dissemination in high-risk patients.high-risk patients.

Drug therapy does not interfere with Drug therapy does not interfere with induction of immunity.induction of immunity.

Treatment in high-risk patientsTreatment in high-risk patients


3.3. Acyclovir also useful for treatment of Acyclovir also useful for treatment of Herpes zoster in dose of 500 mg/m2 or 10 Herpes zoster in dose of 500 mg/m2 or 10 mg/kg 8 hourly.mg/kg 8 hourly.

Treatment of Herpes zosterTreatment of Herpes zoster


PreventionPrevention

1.1. VZV transmission is difficult to prevent VZV transmission is difficult to prevent because the infection is contagious for 24-because the infection is contagious for 24-48 hr before the rash appears.48 hr before the rash appears.

2.2. Infection control practices, including Infection control practices, including caring for infected patients in isolation caring for infected patients in isolation rooms with filtered air systems, are rooms with filtered air systems, are essential. essential.


Prevention – Varicella VaccinePrevention – Varicella Vaccine

1.1. Composition : Live virus (min. Composition : Live virus (min. 2000 PFU) (Oka/Merck strain).2000 PFU) (Oka/Merck strain).

2.2. Efficacy : 95% (65%-100%).Efficacy : 95% (65%-100%).3.3. Duration of : > 7 years.Duration of : > 7 years.4.4. Vaccination Schedule : 1 Dose Vaccination Schedule : 1 Dose

subcutaneous (<13 years of age).subcutaneous (<13 years of age).5.5. May be administered May be administered

simultaneously with measles, simultaneously with measles, mumps, and rubella (MMR) mumps, and rubella (MMR) vaccine.vaccine.


1.1. Routine vaccination at 15-18 months of Routine vaccination at 15-18 months of age.age.

2.2. Recommended for all children without Recommended for all children without evidence of Varicella immunity by the evidence of Varicella immunity by the 13th birthday.13th birthday.

Prevention – Prevention – Varicella Vaccine for children Varicella Vaccine for children


1.1. Recommended to all persons Recommended to all persons >>13 years 13 years of age without evidence of Varicella of age without evidence of Varicella immunity.immunity.

2.2. Two doses separated by 4-8 weeks.Two doses separated by 4-8 weeks.

3.3. Do not repeat first dose because of Do not repeat first dose because of extended interval between doses.extended interval between doses.

Prevention – Varicella Vaccine Prevention – Varicella Vaccine for adolescents and adultsfor adolescents and adults


Varicella Vaccine – Varicella Vaccine – Adverse ReactionsAdverse Reactions

1.1. Injection site complaints – Injection site complaints – 19% (children) 19% (children) 24% (adolescents and adults). 24% (adolescents and adults).

2.2. Rash – 3 – 4% of vaccinees. Rash – 3 – 4% of vaccinees.

1.1. Rash may be maculopapular ratherRash may be maculopapular ratherthan vesicular.than vesicular.

2.2. Average 5 lesions.Average 5 lesions.

3.3. Systemic reactions not common.Systemic reactions not common.


Zoster following VaccinationZoster following Vaccination

1.1. Most cases in children.Most cases in children.

2.2. Risk from vaccine virus less than from Risk from vaccine virus less than from wild virus.wild virus.

3.3. Usually a mild illness without Usually a mild illness without complications.complications.


Transmission of Varicella Transmission of Varicella Vaccine VirusVaccine Virus

1.1. Transmission of vaccine virus not Transmission of vaccine virus not common.common.

2.2. Asymptomatic seroconversion may occur Asymptomatic seroconversion may occur in contacts without evidence of Varicella in contacts without evidence of Varicella immunity.immunity.

3.3. Risk of transmission increased if vaccinee Risk of transmission increased if vaccinee develops rash.develops rash.


Varicella Vaccine – Varicella Vaccine – Contraindications and PrecautionsContraindications and Precautions

1.1. Severe allergic reaction to vaccine Severe allergic reaction to vaccine component or following a prior dose.component or following a prior dose.

2.2. Immunosuppression.Immunosuppression.

3.3. Pregnancy.Pregnancy.

4.4. Moderate or severe acute illness.Moderate or severe acute illness.

5.5. Recent blood product transfusion.Recent blood product transfusion.


ConclusionsConclusions

1.1. Varicella or Chickenpox is a vaccine Varicella or Chickenpox is a vaccine preventable disease occuring commonly in preventable disease occuring commonly in children.children.

2.2. It is characterized by fever & pleomorphic It is characterized by fever & pleomorphic rash in centripetal distribution.rash in centripetal distribution.

3.3. It causes many complications if it occurs It causes many complications if it occurs in adults.in adults.


MCQsMCQs

1.1. ““Pleomorphism” is the characterstic of rash Pleomorphism” is the characterstic of rash of :of :

1.1. Measles.Measles.

2.2. HHV – 3.HHV – 3.

3.3. Smallpox.Smallpox.

4.4. Fifth disease.Fifth disease.

Ans. – 2.


MCQsMCQs

2.2. A child presenting with fever and Varicella A child presenting with fever and Varicella rash on day 1 :rash on day 1 :

1.1. Has already transmitted the virus to other Has already transmitted the virus to other children.children.

2.2. Is infectious to his siblings.Is infectious to his siblings.

3.3. Will continue to infect others for 4 – 5 days.Will continue to infect others for 4 – 5 days.

4.4. All of the above.All of the above.

5.5. Only 1 & 2 are correct.Only 1 & 2 are correct.

Ans. – 4.


MCQsMCQs

3.3. Following are not false about “Congenital Following are not false about “Congenital Varicella Syndrome” except: Varicella Syndrome” except: (multiple choice)(multiple choice)

1.1. Risk of transmission is maximum in the 2Risk of transmission is maximum in the 2ndnd trimester of pregnancy.trimester of pregnancy.

2.2. Extensive involvement of neurological system of Extensive involvement of neurological system of foetus.foetus.

3.3. Hyper-pigmentation of skin is pathognomic sign.Hyper-pigmentation of skin is pathognomic sign.

4.4. If fetus is born alive, may have problem in If fetus is born alive, may have problem in defecation and micturition.defecation and micturition.

Ans. – 1,3.


MCQsMCQs

4.4. Complications of Varicella : Complications of Varicella : (multiple choice)(multiple choice)

1.1. Occur more commonly in children infected Occur more commonly in children infected within first 5 years of life.within first 5 years of life.

2.2. Pnuemonia is more common in adults.Pnuemonia is more common in adults.

3.3. Can be prevented by early administration of Can be prevented by early administration of Acyclovir.Acyclovir.

4.4. Varicella gangrenosa is a life-threatening Varicella gangrenosa is a life-threatening infection caused by superadded infection caused by superadded Clostridium Clostridium infection.infection.

Ans. – 2,3.


MCQsMCQs

5.5. All are false about Varicella vaccine except : All are false about Varicella vaccine except : (multiple choice)(multiple choice)

1.1. It may be given along with MMR vaccine (live It may be given along with MMR vaccine (live vaccine).vaccine).

2.2. AIDS patients, not having previous history of AIDS patients, not having previous history of Varicella, should receive this vaccine.Varicella, should receive this vaccine.

3.3. The child is 100% protected for his entire life.The child is 100% protected for his entire life.

4.4. A susceptible female should be immunized in the A susceptible female should be immunized in the first trimester of pregnancy itself .first trimester of pregnancy itself .

Ans. – 1.


Differences between Smallpox Differences between Smallpox and Chickenpoxand Chickenpox SmallpoxSmallpox

Incubation – About 12 Incubation – About 12 days (range 7-17 days)days (range 7-17 days)

Prodromal symptoms - Prodromal symptoms - Usually mildUsually mild

Distribution of rash – Distribution of rash – - palms and soles - palms and soles

frequently involvedfrequently involved - axilla usually free- axilla usually free - rash predominant on - rash predominant on

extensor surfaces and bony extensor surfaces and bony prominencesprominences

ChickenpoxChickenpox About 15 days (range 7-About 15 days (range 7-

21 days)21 days) Usually mildUsually mild - seldom affected- seldom affected - axilla affected- axilla affected - rash mostly on flexor - rash mostly on flexor

surfacessurfaces


Characteristics of the rashCharacteristics of the rash – – - deep-seated- deep-seated - vesicles multilocular - vesicles multilocular

and umbilicatedand umbilicated - only one stage of rash - only one stage of rash

may be seen at one timemay be seen at one time - No area of - No area of

inflammation is seen inflammation is seen around the vesiclesaround the vesicles

superficialsuperficial - unilocular; dew-drop like - unilocular; dew-drop like

appearanceappearance - rash pleomorphic, I.e. - rash pleomorphic, I.e.

different stages of the rash different stages of the rash evident at one given time, evident at one given time, because rash appears in because rash appears in successive cropssuccessive crops

- an area of inflammation - an area of inflammation is seen around the is seen around the vesiclesvesicles


Evolution of rashEvolution of rash

evolution of rash is evolution of rash is slow, deliberate and slow, deliberate and majestic, passing majestic, passing through definite stages through definite stages of macule, papule, of macule, papule, vesicle and pustulevesicle and pustule

- scabs begin to form - scabs begin to form 10-14 days after the 10-14 days after the rash aprash ap

evolution of rash very evolution of rash very rapidrapid

- scabs begin to form - scabs begin to form 4-7 days after the rash 4-7 days after the rash appearsappears


FeverFever

- Fever subsides with the - Fever subsides with the appearance of rash, but appearance of rash, but may rise again in the may rise again in the pustular stage pustular stage (secondary rise of fever)(secondary rise of fever)

Temperature rises with Temperature rises with

each fresh crop of rasheach fresh crop of rash

chickenpox (varicella)

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