Chickenpox (varicella) in children who are immunocompetent

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.

Neonates are at an increased risk of severe disease and complications of chickenpox (eg pneumonitis, encephalitis, hepatitis). For the management of neonates exposed to varicella zoster virus, including those born to a birthing parent (eg mother) with perinatal chickenpox infection, see the Australasian Society for Infectious Diseases (ASID) Management of Perinatal Infections guidelines.

Note: Neonates are at increased risk of severe disease and complications of chickenpox.

In children 1 month to 12 years of age who are immunocompetent, chickenpox is usually mild and self-limiting. The mainstay of therapy is supportive care, including:

  • 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.

Antiviral therapy is not usually recommended for chickenpox in children 1 month to 12 years of age who are immunocompetent because the benefit is smallCenter for Disease Control (CDC), 2022.

However, antiviral therapy may be recommended for immunocompetent children who are at increased risk of severe chickenpox, including extensive cutaneous lesions and complications (eg pneumonitis, encephalitis, hepatitis). This includes childrenCenter for Disease Control (CDC), 2022:

  • with significant pre-existing skin disease (eg eczema)
  • with chronic lung disease
  • using inhaled or oral corticosteroids
  • older than 12 years who have not been vaccinated for chickenpox.

If antiviral therapy is recommended for chickenpox in children who are immunocompetent, irrespective of rash duration, use:

1aciclovir 20 mg/kg up to 800 mg orally, 5 times daily for 7 days1 aciclovir

OR

1valaciclovir (child 2 years or older) 20 mg/kg up to 1 g orally, 8-hourly for 7 days23. valaciclovir

For management of immunocompetent children with complications of chickenpox (eg pneumonitis, encephalitis, hepatitis) and children with immune compromise who develop chickenpox, see here.

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 children exposed to varicella zoster virus, including the use of varicella vaccine or high-titre zoster immunoglobulin (ZIG), see the Australian Immunisation Handbook.

1 Aciclovir dosing in obesity is poorly defined; however, limited data support dosing based on ideal body weight in children.Return
2 An oral liquid formulation of valaciclovir is not commercially available; for formulation options for children or people with swallowing difficulties, see Don’t Rush to Crush, which is available for purchase from the Advanced Pharmacy Australia website or through a subscription to eMIMSplus.Return
3 Valaciclovir is not licensed in Australia for use in children younger than 12 years; however, it is licensed internationally for use in children older than 2 years.Return