AUTHOR AND EDITOR INFORMATION

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

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Background

Varicella, or chickenpox, is usually a benign, self-limited, primary infection that affects approximately 4 million children per year in the United States. Varicella also accounts for significant morbidity (4000 hospitalizations per year) and mortality (50-100 deaths per year) in otherwise healthy children; moreover, the annual cost of chickenpox has been estimated at $400 million in medical costs and lost wages in the past. Universal immunization against varicella was first recommended in 1995 and has lead to a reduction in varicella related hospitalizations and hospital related charges for children and adults in the United States.

Pathophysiology

Primary varicella is caused by the varicella-zoster (V-Z) virus, a herpes virus. Inhalation of virus-infected respiratory secretions or direct contact with skin lesions can produce disease.

Infection usually occurs through the conjunctival or upper respiratory mucosa. Viral replication takes place in regional lymph nodes over the next 2-4 days and is followed by a primary viremia occurring 4-6 days after initial inoculation. The virus then replicates in the liver, spleen, and possibly other organs. This secondary viremia, featuring viral particles being spread to the skin 14-16 days after initial exposure, causes the typical vesicular rash. Encephalitis, hepatitis, or pneumonia also may occur at this time.

The usual incubation period is 10-21 days. The patient is contagious from 1-2 days before the appearance of rash until the lesions crust over, usually 5-6 days after the rash first appears.

Although most varicella infection confers life-long immunity, varicella clinical reinfections among healthy children have been described.

Frequency

United States

Prevalence is seasonal, with annual peaks in March and April.

International

Varicella is almost universal; an estimated 60 million cases occur worldwide each year. A survey of 1473 cases in Japan demonstrated that 81.4% involved children younger than 6 years. In Japan, the annual prevalence peaked between March and May, with subsequent lower prevalence between August and October.

Mortality/Morbidity

In immunocompromised children, such as those with leukemia, mortality rates from varicella have ranged from 7-28%. The case fatality rate in the general population is 6.7/100,000.

• Morbidity is due to overwhelming viremia, encephalitis, bacterial superinfection, pneumonia, and Reye syndrome (which is associated with aspirin use). Common complications include secondary staphylococcal or streptococcal infections of the skin and upper respiratory tract, including otitis media. Central nervous system complications include aseptic meningitis and Guillain-Barré syndrome. Other complications include thrombocytopenia, arthritis, hepatitis, and glomerulonephritis.
• In pregnant women, varicella during the first 20 weeks of gestation can lead to multiple congenital anomalies including limb atrophy, neurologic and ocular abnormalities, as well as growth retardation.
• Infants born to women who have varicella 5 days or fewer before delivery or 2 days postpartum may develop disseminated varicella neonatorum. Hemorrhagic lesions of the liver and lungs characterize this potentially fatal disease.

Sex

Varicella has no sex predilection.

Age

Varicella is most commonly observed in children aged 3-6 years.

• Though most cases of varicella in the United States occur in children younger than 10 years, 5% of cases are in persons older than 15 years.
• In tropical climates, varicella is more common in older children.
• The majority of cases in Japan were in children younger than 6 years. Approximately 9.6% of cases involved children younger than 1 year, and almost one third of these were infants younger than 5 months.

CLINICAL

Section 3 of 11  

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• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

• The history should describe if a recent outbreak of chickenpox in the community has occurred and if any exposure to varicella at school, daycare, or among family members has occurred. It should also be noted whether the child has previously received varicella vaccine or if the child is immunocompromised.
• Ask parents whether their child had chickenpox previously.
• Prodromal symptoms
• • Fever
  • Malaise
  • Anorexia
  • Headache
• Lesions erupt in successive crops, usually beginning on the trunk and then spreading to the face and scalp.
• Lesions frequently involve the pharynx and tonsils.
• The rash is most often described as being very itchy.
• A careful history should investigate the possibility of immunodeficiency (including recent systemic steroid use) to help guide management.

Physical

The diagnosis is made with the characteristic rash. Ill appearance should raise concern for pulmonary or CNS complications or serious bacterial superinfection.

• The classic lesion has been described as an "oval teardrop on an erythematous base" or a "dew drop on a rose petal."
• Skin lesions initially appear on the face and trunk, beginning as red macules and progressing over 12-14 days to become papular, vesicular, pustular, and finally crusted.
• The lesions predominate in central skin areas and proximal upper extremities with relative sparing of distal and lower extremities but spread to other skin areas.
• A characteristic feature of the rash is that the lesions can be in all stages of development simultaneously.
• Vesicles may occur on mucous membranes and break down to form shallow aphthous ulcers.
• A patient's temperature can be as high as 39.5°C and can last 3-6 days after the development of the rash.
• Vesicles can be hemorrhagic.
• Dermatomal distribution of lesions is characteristic of reactivation rather than primary infection.
• Identify right upper quadrant pain with or without associated jaundice.
• Although tachypnea may be seen with fever alone, respiratory distress might represent pneumonitis.
• A careful neurologic examination can identify associated meningo-encephalitis.
• Cerebellitis, as noted by ataxia, is associated with varicella infection.
• Look for signs of bacterial superinfection.
• • Superficial infection with impetigo
  • Cellulitis
  • Necrotizing fasciitis

Causes

• Human (alpha) herpesvirus 3 (V-Z virus), a member of the herpesvirus group, is responsible for the development of varicella.
• Direct person-to-person contact with lesions and/or airborne droplets spreads the V-Z virus. Neonatal varicella is caused by maternal viremia, leading to spread of the virus across the placenta.
• Risk factors
• • No prior history of varicella
  • Unvaccinated status
  • Immunosuppression

DIFFERENTIALS

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Other Problems to be Considered

Measles
Meningococcemia (can be confused with hemorrhagic varicella)
Other common viral exanthems (eg, coxsackievirus, echovirus)
Smallpox (no cases since 1949; virus officially destroyed in 1996)
Drug eruption
Papular urticaria
Dermatitis herpetiformis
Eczema herpeticum

WORKUP

Section 5 of 11  

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Lab Studies

• Varicella is usually a clinical diagnosis.
• Laboratory tests, such as those listed below, are available for confirmation, but they are rarely required.
• The white blood cell (WBC) count may be normal, low, or mildly elevated.
• Marked leukocytosis suggests a secondary infection.
• Culture of the base of the vesicle, direct electron microscopy, and immunofluorescence staining of the base of the lesion may be performed for detection of V-Z virus but usually are not necessary.

Imaging Studies

• Imaging studies are not required for varicella unless concerns for secondary complications exist (eg, chest radiograph for varicella pneumonia).

Other Tests

• Bacterial culture of lesions may be indicated if signs of superinfection are present.
• A lumbar puncture for culture, cytology, and chemistries may be performed if signs of CNS involvement are present.

Procedures

• If the diagnosis is equivocal, a Tzanck smear may be performed from a scraping of the base of the varicella lesion. Presence of multinucleated giant cells is suggestive of a herpes virus infection but is not specific for V-Z virus. Infections with other herpes viruses, such as herpesvirus 1 and 2, also display similar multinucleated giant cells.

TREATMENT

Section 6 of 11  

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Prehospital Care

Prehospital care is usually not needed, other than for symptomatic management to reduce complications, particularly secondary skin infections.

Emergency Department Care

• Patients should be isolated from other patients. Special consideration should be given to inadvertent exposures to immunocompromised patients.
• Oral antihistamines, such as diphenhydramine and hydroxyzine, are used for severe pruritus. Caution must be used with topical diphenhydramine; toxicity may occur from systemic absorption if it is applied to the entire body.
• Because of the association of varicella and aspirin therapy leading to Reye syndrome, acetaminophen is recommended for use for the reduction of fever. Studies have also tried to find an association between ibuprofen and risk of fasciitis; studies have not been conclusive.
• Intravenous acyclovir is recommended only for the treatment of varicella in immunocompromised children or in children with varicella pneumonia or encephalitis. Oral acyclovir has been variably recommended for adolescent patients who are early in their illness. Additionally, antiviral therapy should be considered for patients with recent steroid use or those with extensive eczema.
• Varicella-zoster immune globulin (VZIG) is recommended within 96 hours of a significant exposure for high-risk susceptible patients. The dose is 125 U/10 kg body weight (minimum dose is 125 U; maximum 625 U IM).

Consultations

Consultation with a pediatric infectious disease specialist, as well as a pediatric intensivist, may be required for cases of progressive varicella (with coexisting defect in cell-mediated immunity) and for such complications as CNS involvement or invasive infection by group A beta-hemolytic streptococci such as necrotizing fasciitis.

MEDICATION

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Treatment of varicella is supportive.

Drug Category: Antihistamines

Act by competitive inhibition of histamine at the H1 receptor. Mediate wheal and flare reactions, bronchial constriction, mucous secretion, smooth muscle contraction, edema, hypotension, CNS depression, and cardiac arrhythmias.

Drug Category: Antiviral Agent

Used for treatment of immunocompromised children or in healthy children who develop varicella pneumonia or encephalitis. The routine use of acyclovir in healthy children is not universally recommended. In some instances acyclovir may be considered for teenagers and adults with otherwise uncomplicated varicella.

Drug Category: Antipyretic

Used for fever control. Unlike aspirin, acetaminophen is not associated with Reye syndrome when administered during varicella infection.

Drug Category: Immune Globulin

Provides passive immunization for susceptible individuals when administered with 96 h of exposure.

FOLLOW-UP

Section 8 of 11  

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Further Inpatient Care

• Inpatient care requires strict isolation from other patients and susceptible healthcare workers. A negative pressure room is ideal.

Further Outpatient Care

• Warm soaks and oatmeal or cornstarch baths may reduce itching and provide comfort.
• Topical calamine lotion may produce caking of lesions and excessive drying of the skin, causing the child to scratch.

Transfer

• Most cases of hospitalized uncomplicated varicella do not require transfer to a tertiary care pediatric facility.
• Immunocompromised children with varicella may develop significant morbidity and mortality and should be transferred to a tertiary care pediatric center.
• Similarly, patients with complications of varicella, such as pneumonia, encephalitis, or severe skin manifestations such as necrotizing fascitis, should be transferred to a tertiary pediatric facility.

Deterrence/Prevention

• For susceptible individuals (see below) passive immunization with VZIG is effective against varicella if given within 96 hours of exposure.
• • Immunocompromised children
  • Susceptible pregnant women
  • Newborns whose mothers had varicella within 5 days prior to delivery or within 48 hours after delivery
• Hospitalized premature infants of 28 weeks gestation or fewer whose mothers have no history of varicella infection. Also, VZIG should be given to hospitalized premature infants (28 wk gestation or fewer or fewer than 1000 g) regardless of maternal history when a significant exposure has occurred.
• Universal active immunization with 0.5 mL of wild Oka strain attenuated varicella vaccine is recommended once for children aged 12-18 months who lack a reliable history of varicella.
• One dose of varicella vaccine can be given at any time to susceptible children aged 19 months to 13 years.
• From age 13 years to young adulthood, varicella vaccine can be given to individuals without prior infection or immunization (2 doses separated by 4-8 wk).

Complications

• In immunocompetent children, complications are rare. Skin superinfection is manifested by impetigo, furuncles, cellulitis, and erysipelas. The most severe complication is necrotizing fascitis.
• The most common complication is scarring and may be associated with staphylococcal or streptococcal infections from scratching.
• Extracutaneous complications increase proportionately to the age of the patient.
• Neurologic complications include Reye syndrome, acute cerebellar ataxia, encephalitis, meningoencephalitis, polyradiculitis, and myelitis (including Guillain-Barré syndrome).
• Other rare complications include myocarditis, glomerulonephritis, appendicitis, pancreatitis, Henoch-Schönlein purpura, orchitis, arthritis, optic neuritis, iritis, and keratitis.
• Varicella pneumonia is a complication usually of adult varicella and occurs in 1:400 cases.
• Immunocompromised children with varicella are at high risk for developing progressive varicella with multiple organ involvement.

Prognosis

• The prognosis of uncomplicated varicella is excellent.
• The mortality rate of adult varicella pneumonia is as high as 10% in immunocompetent patients and as high as 30% in immunocompromised patients.
• Immunocompromised children with varicella have significant morbidity and mortality.
• Infection confers life-long immunity, although secondary reinfection has been reported.
• Rarely, fatalities may occur from complications.

Patient Education

• To avoid Reye syndrome, use acetaminophen for fever. Do not use aspirin.
• Drink plenty of fluids.
• Keep nails short and have child wear socks on hands at bedtime to avoid scratching.
• Use medication for itching as prescribed by the physician.
• Children with chicken pox should avoid nonimmune pregnant women, unimmunized young infants, and others with immunodeficiencies or who are taking prednisone long term.
• Children with chicken pox may not return to school or day care until all lesions are crusted over.
• Speak to a physician or go to the emergency department if any of the following occur:
• • The blisters look infected.
  • A change in the child's behavior occurs.
  • Blisters are observed in the child's eyes.
  • The child has trouble breathing.
  • The child has a severe headache or has trouble walking.
  • The fever persists after the third day, or the fever was gone and then came back.
• For excellent patient education resources, visit eMedicine's Bacterial and Viral Infections Center. Also, see eMedicine's patient education articles Chickenpox and Skin Rashes in Children.

MISCELLANEOUS

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Medical/Legal Pitfalls

• Although varicella is a self-limited illness of childhood, several medical legal pitfalls should be considered.
• • Problems arise when hospitalized patients who have been exposed to varicella are not appropriately isolated from high-risk inpatients who are immunocompromised. Mortality and morbidity rates from varicella are increased in immunocompromised children.
  • Failure to recognize streptococcal or staphylococcal superinfection and the need for antibiotics is also a pitfall.

Special Concerns

• Varicella in pregnancy is of special concern because it can lead to intrauterine varicella or varicella of the newborn.
• • Intrauterine varicella during the first 20 weeks of gestation may lead to congenital anomalies including limb atrophy, neurologic and ocular abnormality, and growth retardation of the neonate.
  • Infants born at term to mothers who had onset of a varicella rash within 5 days before and 2 days after delivery may develop a fatal form of varicella (varicella neonatorum). This occurs because of the infant does not receive transplacental V-Z antibody.
  • If varicella exposure to the infant occurs after the tenth day of life, the illness is usually benign and self-limiting.

MULTIMEDIA

Section 10 of 11  

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• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Papulovesicular lesions on arm in varying stages of healing in this infant with varicella. Photograph courtesy of Susan Feigelman, MD.
	View Full Size Image
Media type:  Photo

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

• American Academy of Pediatrics Committee on Infectious Diseases. The use of oral acyclovir in otherwise healthy children with varicella. Pediatrics. 1993;91(3):674-6. [Medline].
• Arvin A. Progress in the treatment and prevention of varicella. Curr Opin Infect Dis. 1993;6:553-557.
• Braun I. Varicella zoster virus: trends and treatment. MCN Am J Matern Child Nurs. Jul-Aug 1996;21(4):187-90. [Medline].
• Cowan MR, Primm PA, Scott SM, et al. Serious group A beta-hemolytic streptococcal infections complicating varicella. Ann Emerg Med. Apr 1994;23(4):818-22. [Medline].
• Davis MM, Patel MS, Gebremariam A. Decline in varicella-related hospitalizations and expenditures for children and adults after introduction of varicella vaccine in the United States. Pediatrics. Sep 2004;114(3):786-92. [Medline].
• Doctor A, Harper MB, Fleisher GR. Group A beta-hemolytic streptococcal bacteremia: historical overview, changing incidence, and recent association with varicella. Pediatrics. Sep 1995;96(3 Pt 1):428-33. [Medline].
• Drwal-Klein LA, O'Donovan CA. Varicella in pediatric patients. Ann Pharmacother. Jul-Aug 1993;27(7-8):938-49. [Medline].
• Georges P, ed. Varicella-zoster infections. In: 1997 Red Book Report of the Committee on Infectious Diseases. 1997:573-85.
• Hall S, Maupin T, Seward J, et al. Second varicella infections: are they more common than previously thought?. Pediatrics. Jun 2002;109(6):1068-73. [Medline].
• Lesko SM, O'Brien KL, Schwartz B, Vezina R, Mitchell AA. Invasive group A streptococcal infection and nonsteroidal antiinflammatory drug use among children with primary varicella. Pediatrics. May 2001;107(5):1108-15. [Medline].
• Newman RD, Taylor JA. Reactions of pediatricians to the recommendation for universal varicella vaccination. Arch Pediatr Adolesc Med. Aug 1998;152(8):792-6. [Medline].
• Resnick SD. New aspects of exanthematous diseases of childhood. Dermatol Clin. 1997;15:257-66. [Medline].
• Rockley PF, Tyring SK. Pathophysiology and clinical manifestations of varicella zoster virus infections. Int J Dermatol. Apr 1994;33(4):227-32. [Medline].
• Seward JF, Zhang JX, Maupin TJ. Contagiousness of varicella in vaccinated cases: a household contact study. JAMA. Aug 11 2004;292(6):704-8. [Medline].
• Seward JF, Watson BM, Peterson CL. Varicella disease after introduction of varicella vaccine in the United States, 1995-2000. JAMA. Feb 6 2002;287(5):606-11. [Medline].

Article Last Updated: Jun 13, 2006