Chickenpox: Symptoms and Treatment
Clinical Presentation
Chickenpox typically presents with a characteristic pruritic vesicular rash accompanied by fever, headache, fatigue, myalgia, and chills. 1
The rash progresses through stages: macules → papules → vesicles → crusted lesions, with new crops appearing over several days. Lesions typically appear first on the trunk and face, then spread to extremities. 1
Treatment Approach
Immunocompetent Patients
Most immunocompetent children with chickenpox require only symptomatic management without antiviral therapy. 1, 2
However, antiviral therapy with acyclovir is recommended for patients at higher risk for complications, specifically:
- All patients over 12 years of age 1
- Patients with chronic cutaneous or pulmonary disorders 1
- Patients receiving long-term salicylate therapy or corticosteroid therapy 1
Acyclovir Dosing
For children <45 kg: 20 mg/kg (maximum 400 mg/dose) orally 4 times daily for 5 days 1, 3
For adults and children >40 kg: 800 mg orally 4 times daily for 5 days 1, 3
Timing is critical: Therapy must be initiated within 24 hours of rash onset for maximum benefit. 3, 4 Starting treatment beyond this window significantly reduces efficacy. 3
Immunocompromised Patients
Immunocompromised patients require aggressive treatment with intravenous acyclovir at 10 mg/kg IV every 8 hours. 1, 5
Critical management steps for immunocompromised patients include: 1
- Immediately discontinue immunomodulator therapy during active infection 1
- Never initiate immunomodulator therapy during active chickenpox 1
- Immunomodulator therapy can only be reintroduced after all vesicles have crusted over and fever has resolved 1
Immunocompromised patients face substantially higher risk of severe complications including pneumonia (44.4% of viral complications), hemorrhagic rash (44.4%), hepatitis, encephalitis, and death. 1, 5 In one review, 5 of 20 varicella cases in IBD patients proved fatal, highlighting the severity in this population. 1
Severe Disease Requiring IV Therapy
Intravenous acyclovir (10 mg/kg every 8 hours for 7-10 days) is indicated for: 3, 5, 6
- All immunocompromised patients 1, 3
- Varicella pneumonia 5, 6
- Hemorrhagic varicella 5
- CNS complications (encephalitis, meningitis) 5, 6
- Visceral dissemination 5, 6
Adequate hydration and urine flow must be maintained during IV therapy, mental status monitored, and dosing adjusted for renal impairment. 3, 6
Post-Exposure Prophylaxis
Varicella-Zoster Immune Globulin (VZIG) is first-line prophylaxis for high-risk susceptible individuals and must be administered within 96 hours of exposure. 7, 1
High-risk individuals requiring VZIG include: 7, 1
- Immunocompromised patients 7, 1
- Pregnant women without immunity 1
- Premature infants born to susceptible mothers 7
- Infants born at <28 weeks gestation or weighing ≤1,000 grams regardless of maternal immune status 7
Alternative prophylaxis: If VZIG is unavailable, acyclovir 20 mg/kg (maximum 800 mg) orally 4 times daily for 5-7 days, initiated 7-10 days after exposure, may be considered. 1
Post-exposure vaccination within 3-5 days may modify disease if infection has not yet occurred. 1
Infection Control
Patients with active chickenpox must be isolated until all lesions have crusted over. 1
Healthcare workers without evidence of immunity who are exposed to VZV should be furloughed from days 10-21 after exposure. 7, 1 Evidence of immunity includes documentation of 2 doses of varicella vaccine, laboratory evidence of immunity, or laboratory confirmation of prior disease. 7
Airborne transmission of VZV has been documented in healthcare settings, with transmission occurring to patients and staff who had no direct contact with the index case. 7
Vaccination Considerations
Varicella vaccine should NOT be administered to immunocompromised patients due to risk of disseminated viral infection. 1
For varicella-naive patients requiring immunosuppressive therapy: Complete the two-dose varicella vaccine series at least 3 weeks prior to starting any immunomodulator or immunosuppressive therapy. 1 If already on immunosuppression, vaccination requires a 3-6 month cessation of all immunosuppressive therapy before and after administration. 1
Household contacts of immunocompromised individuals should be vaccinated if seronegative. 1
Common Pitfalls to Avoid
Never assume immunity based on age alone—always verify history or serology. 1 While 97-99% of adults with a positive history of varicella are seropositive, 30-35% of adults without clear history remain susceptible. 7, 1
Never continue immunosuppressive therapy during active varicella infection in severe cases—this substantially increases mortality risk. 1
Do not delay antiviral therapy beyond 24 hours of rash onset in patients requiring treatment—efficacy decreases significantly. 3, 4
Avoid salicylates (aspirin) in children with chickenpox due to risk of Reye syndrome. 1