How is varicella (chickenpox) managed?

Treatment of Chickenpox (Varicella)

For otherwise healthy children and adults with uncomplicated chickenpox, supportive care alone is the primary treatment; routine antiviral therapy is not indicated because the marginal benefit does not justify the requirement to start within 24 hours of rash onset. 1

Supportive Care Measures (All Patients)

Supportive care is the cornerstone of treatment for immunocompetent patients without complications. 1, 2

• Itch relief: Administer lukewarm baths with colloidal oatmeal to reduce pruritus 1, 3
• Hydration: Ensure adequate fluid intake and monitor for signs of dehydration, particularly in young children 1
• Skin protection: Keep fingernails trimmed short to minimize scratching and reduce risk of secondary bacterial infection 1
• Fever management: Use acetaminophen for fever control 1
• Critical medication precaution: Never use aspirin or any salicylate-containing products due to established risk of Reye syndrome 1
• Ibuprofen consideration: May be avoided due to limited evidence suggesting increased risk of invasive group A streptococcal infection 1

Oral Acyclovir: When to Consider

Oral acyclovir is only effective if initiated within 24 hours of rash onset and should be considered only for specific high-risk groups. 1, 4, 5

High-Risk Groups for Oral Acyclovir:

• Adolescents and adults ≥13 years (otherwise healthy, non-pregnant): 800 mg orally 4 times daily for 5 days 1, 4
• Children >12 months with chronic cutaneous or pulmonary disorders: 20 mg/kg per dose orally 4 times daily (maximum 800 mg per dose) for 5 days 1, 4
• Children receiving long-term salicylate therapy: Same dosing as above 1
• Secondary household cases (expert opinion): Same dosing as above 1
• Children over 40 kg: Receive adult dose of 800 mg 4 times daily for 5 days 4

Why Routine Use Is Not Recommended:

The benefit is modest—approximately 1 day reduction in fever and only 15-30% decrease in overall symptom severity—which does not outweigh the logistical challenge of starting treatment within the narrow 24-hour window. 1

Intravenous Acyclovir: Mandatory for Immunocompromised Patients

Intravenous acyclovir is mandatory for all immunocompromised children and adults with chickenpox. 1, 3, 4

Standard IV Dosing:

• 10 mg/kg every 8 hours for 7-10 days OR until no new lesions appear for 48 hours 1, 3
• Alternative dosing for children >1 year: 500 mg/m² every 8 hours 3
• For severe immune suppression (CDC category 3): Continue IV therapy for the full 7-10 day course regardless of lesion status 3

Immunocompromised Populations Requiring IV Therapy:

• Patients undergoing immunosuppressive therapy 6, 1
• Patients with malignant disease 6, 1
• HIV-infected patients (except CDC class 1 with CD4 ≥15%) 3
• Patients with congenital nephrotic syndrome or hypogammaglobulinemia 3

Monitoring for Complications

Bacterial superinfection is the most common serious complication requiring hospitalization and must be identified early. 1, 3

Warning Signs of Bacterial Superinfection:

• Expanding erythema around lesions 1, 3
• Purulent drainage from lesions 1, 3
• Increasing pain or tenderness 1, 3
• Systemic toxicity: high fever, lethargy, tachycardia 1, 3
• Invasive group A streptococcal infection is the most frequent bacterial complication 1, 3

Other Serious Complications to Monitor:

• Pneumonia: More common in adults and infants <1 year 1, 3
• Dehydration: Especially in young children 1
• Encephalitis: Rare but serious 1
• Cerebellar ataxia: Rare neurological complication 1

High-Risk Populations for Severe Disease:

• Infants <1 year: 6-fold higher risk of hospitalization compared with children aged 5-9 years 1, 3
• Pregnant women: At increased risk for severe varicella disease and complications 6
• Premature infants born to susceptible mothers 6
• Infants born at <28 weeks' gestation or weighing ≤1000 grams regardless of maternal immune status 6

Isolation and Infection Control

Patients are contagious from 1-2 days before rash onset until all lesions have crusted (typically 5-7 days after rash onset). 1, 7

Isolation Requirements:

• Keep the patient isolated until all lesions have crusted 1, 3
• Persons in whom varicella develops are infective until all lesions dry and crust 6
• Hospitalized patients require airborne and contact precautions 6

Avoid Contact With:

• Immunocompromised individuals 1, 3
• Pregnant women lacking immunity 1, 3
• Newborns 1, 3
• Unvaccinated susceptible contacts 1, 3

Post-Exposure Prophylaxis for Contacts

Varicella vaccine given within 3-5 days of exposure provides excellent protection and should be the first-line post-exposure prophylaxis for susceptible contacts. 1, 3, 8

Vaccine Post-Exposure Prophylaxis:

• >90% efficacy if administered within 3 days of exposure 1, 3
• ≈70% efficacy if given within 5 days of exposure 1, 3
• 100% effective at preventing severe disease even when breakthrough infection occurs 1, 3

Varicella-Zoster Immune Globulin (VariZIG):

VariZIG within 10 days of exposure is indicated for high-risk individuals who cannot receive vaccine: 1, 3

• Immunocompromised contacts 1, 3
• Pregnant women without evidence of immunity 1, 3
• Newborns whose mothers developed varicella 5 days before to 2 days after delivery 1, 3
• Premature infants ≥28 weeks gestation whose mothers lack immunity 1, 3
• Premature infants <28 weeks or <1000 g regardless of maternal immunity 1, 3

Note: VariZIG does not necessarily prevent varicella and may prolong the incubation period from 21 to 28 days. 6

Duration of Treatment and Follow-Up

• Supportive care: Continue until all lesions have crusted (approximately 5-7 days) 1, 3
• IV acyclovir for immunocompromised patients: 7-10 days or until no new lesions for 48 hours 1, 3, 4
• Most cases resolve without complications within 5-7 days 1, 3
• Routine follow-up is unnecessary unless complications develop 1, 3
• Parents should return immediately if warning signs of bacterial superinfection appear 1, 3

Vaccination After Natural Infection

After full recovery from natural varicella, no additional varicella vaccination is required because natural infection confers lifelong immunity. 1, 3

Renal Dose Adjustment

For patients with renal impairment, acyclovir dosing must be adjusted based on creatinine clearance. 4

Dosing for 800 mg every 4 hours regimen:

• CrCl >25 mL/min: 800 mg every 4 hours, 5 times daily 4
• CrCl 10-25 mL/min: 800 mg every 8 hours 4
• CrCl 0-10 mL/min: 800 mg every 12 hours 4
• Hemodialysis: Administer additional dose after each dialysis session 4

Common Pitfalls to Avoid

• Do not prescribe acyclovir routinely for healthy children with uncomplicated disease 1, 2
• If acyclovir is indicated, do not delay beyond 24 hours after rash onset—efficacy is lost 1, 4, 5
• Never use aspirin or salicylates due to Reye syndrome risk 1
• Do not miss bacterial superinfection—it is the leading cause of hospitalization 1, 3
• Do not confuse oral dosing (20 mg/kg QID for children, 800 mg QID for adults) with IV dosing (10 mg/kg TID) for immunocompromised patients 1, 4
• Do not vaccinate children with documented prior chickenpox—natural infection provides superior lifelong immunity 1, 3
• Do not assume antiviral therapy immediately renders the patient non-contagious—viral shedding continues until lesions are fully crusted 7