What is the treatment for chicken pox?

Treatment of Chickenpox

For immunocompetent adults and adolescents with chickenpox, oral acyclovir 800 mg five times daily for 5-7 days should be initiated within 24 hours of rash onset to reduce disease severity and complications. 1, 2

Treatment Algorithm by Patient Population

Immunocompetent Adults and Adolescents (>12 years)

• Oral acyclovir 800 mg 4-5 times daily for 5-7 days is recommended when treatment can be started within 24 hours of rash onset 1, 2, 3
• Treatment initiated within the first 24 hours dramatically lessens the rash and clinical illness 3
• Adults and adolescents have more severe disease than children and benefit most from early antiviral therapy 1, 4
• Treatment beyond 24 hours is less effective but may still provide benefit if started within 72 hours 3

Immunocompetent Children (2-12 years, <40 kg)

• Oral acyclovir 20 mg/kg (maximum 400 mg) four times daily for 5 days 1, 2
• Treatment should be initiated within 24 hours of rash onset 2
• Routine treatment is NOT recommended for otherwise healthy children under 13 years unless they are sibling contacts or have other medical conditions 5
• Children over 40 kg should receive the adult dose of 800 mg four times daily 2

Immunocompromised Patients

• Intravenous acyclovir 10 mg/kg every 8 hours for 7-10 days is the standard of care 1, 2, 6
• This includes patients with HIV/AIDS, cancer, those receiving immunosuppressive medications (biologics, JAK inhibitors, corticosteroids ≥20 mg/day for ≥2 weeks, purine analogues, methotrexate), or other immunodeficiencies 7, 1
• IV therapy decreases new lesion formation, halts viral dissemination, and lessens visceral complications 6
• Immunomodulator therapy should be discontinued in severe cases if possible 1

Pregnant Women

• Intravenous acyclovir is indicated for varicella pneumonia or other severe complications 5
• Acyclovir should be used during pregnancy only if potential benefit justifies potential risk to the fetus 2
• Pregnant women are at higher risk for severe infection and complications 4

Neonates

• Intravenous acyclovir for 5-10 days if begun early 5
• Neonates are at high risk for severe disease 4

Special Clinical Situations

Varicella Pneumonia or Severe Complications

• Intravenous acyclovir 10 mg/kg every 8 hours for adults and children with pneumonia or other life-threatening complications 1, 5
• Treatment should be initiated immediately upon diagnosis 5, 4

Patients with Chronic Conditions

• Those with chronic cutaneous or pulmonary disorders should receive oral acyclovir therapy 1
• Patients on long-term salicylate or corticosteroid therapy should receive acyclovir 1

Post-Exposure Prophylaxis

High-Risk Susceptible Contacts

• Varicella zoster immune globulin (VZIG) within 96 hours of exposure for immunocompromised individuals, pregnant women, or neonates 1, 5
• If VZIG is unavailable, acyclovir 7-day course starting 7-10 days after exposure may be considered 1
• Current UK guidelines specifically recommend aciclovir rather than varicella immunoglobulin, with a 7-day course starting 7 days after exposure 7

Healthcare Workers

• Unvaccinated healthcare workers without evidence of immunity who are exposed should be furloughed from days 10-21 after exposure 1
• Post-exposure vaccination should be administered within 3-5 days of exposure 7

Critical Dosing Considerations

Renal Impairment

• Dosage adjustment is mandatory in patients with renal dysfunction 2
• For creatinine clearance 10-25 mL/min: 800 mg every 8 hours 2
• For creatinine clearance 0-10 mL/min: 800 mg every 12 hours 2
• Adequate hydration must be maintained to prevent nephrotoxicity 2, 6

Monitoring Requirements

• Mental status must be monitored for CNS symptoms (reversible with dose adjustment) 2, 6
• Maintain adequate urine flow, especially at higher doses 6
• Caution with concomitant nephrotoxic agents 2

Infection Control

• Isolate patients until all lesions have crusted over 1
• Patients are infectious up to 2 days before rash onset 7
• Avoid contact with immunocompromised individuals, pregnant women, and neonates 7

Common Pitfalls to Avoid

• Do not delay treatment - efficacy drops dramatically after 24 hours of rash onset 3
• Do not use oral acyclovir in immunocompromised patients - IV therapy is required 1, 6
• Do not forget renal dose adjustment - failure to adjust can cause CNS toxicity 2, 6
• Do not administer live varicella vaccine to immunocompromised patients - contraindicated due to risk of disseminated infection 7, 1