Chickenpox (varicella) in patients with immune compromise and immunocompetent patients with complications of chickenpox
Chickenpox (varicella) is caused by a primary infection with varicella zoster virus (VZV). Management of chickenpox depends on the patient’s age, comorbidities, and clinical presentation.
Patients with immune compromise who develop chickenpox are at risk of developing severe infection and complications (eg pneumonitis, encephalitis, hepatitis). Antiviral therapy is recommended, irrespective of rash duration or severity of disease, for chickenpox in patients with immune compromise (including those with HIV infection) and immunocompetent patients with complications of chickenpox. Start antiviral therapy as early as possible.
Oral antiviral therapy may be considered for initial treatment of nonpregnant patients with immune compromise and a milder presentation of chickenpox; however, close clinical review is required. Use:
1valaciclovir 1 g (child 2 years or older: 20 mg/kg up to 1 g) orally, 8-hourly for a minimum of 7 days12. For dosage adjustment in adults with kidney impairment, see valaciclovir dosage adjustment valaciclovir valaciclovir valaciclovir
OR
1famciclovir 500 mg orally, 8-hourly for a minimum of 7 days3. For dosage adjustment in adults with kidney impairment, see famciclovir dosage adjustment famciclovir famciclovir famciclovir
OR
2aciclovir 800 mg (child: 20 mg/kg up to 800 mg) orally, 5 times daily for a minimum of 7 days4. For dosage adjustment in adults with kidney impairment, see aciclovir oral dosage adjustment. aciclovir aciclovir aciclovir
Intravenous antiviral therapy is recommended for initial treatment ofAustralian Society for Infectious Diseases (ASID), 2022Center for Disease Control (CDC), 2022:
- nonpregnant patients with immune compromise and a more severe presentation of chickenpox
- pregnant patients with immune compromise
- all patients with complications of chickenpox (eg pneumonitis, encephalitis, hepatitis).
For patients who require intravenous antiviral therapy, use:
For ongoing management of patients with chickenpox complicated by encephalitis, see Varicella zoster encephalitis.
For detailed advice on the management of pregnant patients with immune compromise or complications of chickenpox, see the Australasian Society for Infectious Diseases (ASID) Management of Perinatal Infections guidelines.
Switch to oral antiviral therapy after significant clinical improvement, and continue treatment for a minimum of 7 days (intravenous + oral). Longer courses of up to 14 days may be required for patients with slow improvement and those with significant immune compromise.
Limited data suggest that valaciclovir (a prodrug of aciclovir) is safe in pregnancy, and some prescribers prefer it because it has a more convenient (8-hourly) dosing regimenAustralian Society for Infectious Diseases (ASID), 2022. There are insufficient data to support the use of famciclovir in pregnancyAustralian Society for Infectious Diseases (ASID), 2022.
Supportive care for patients with chickenpox includes:
- keeping fingernails short to avoid excoriation and secondary bacterial infection
- managing pruritus with an oral antihistamine
- relieving discomfort with paracetamol; managing fever with paracetamol is not routinely required.
Avoid using nonsteroidal anti-inflammatory drugs (NSAIDs) in children with chickenpox because of the possible association with secondary bacterial infectionMikaeloff, 2008. Avoid using aspirin in children with chickenpox because of the rare association with Reye syndrome in children younger than 16 years.
Secondary bacterial infection of chickenpox skin lesions with Streptococcus pyogenes (group A streptococcus [GAS]) or Staphylococcus aureus can occur and should be treated as for cellulitis. If other organisms are identified on culture, alternative antimicrobials may be required.
For management of patients exposed to varicella zoster virus, including the use of varicella vaccine or high-titre zoster immunoglobulin (ZIG), see the Australian Immunisation Handbook.