Chicken Pox

Chickenpox is the manifestation of primary infection with the varicella zoster virus.

Shingles is the reactivation of dormant virus in the dorsal root ganglion.

Chicken pox is highly infectious.

  • Spread is via the respiratory route
  • It can be caught from someone with shingles
  • A patient is infective from 4 days before the rash first appears
  • They remain infective for 5 days after the rash first appears.
  • The incubation period is 10 -21 days


Clinical features tend to be more severe in older children and adults, and include:

  • fever
  • itchy rash starting on the head/trunk before spreading.
  • rash is initially macular then papular then vesicular
  • systemic upset is usually mild.


Management is supportive:

  • keep cool
  • trim nails
  • calamine lotion
  • school exclusion:
    • guidelines now have reverted to the traditional advice:
    • exclude children from school until all vesicles have crusted over (rather than 5 days post onset of rash which had been advocated for a while)
  • Immunocompromised patients and newborns with peripartum exposure should receive varicella zoster immunoglobulin (VZIG). If chickenpox develops then IV aciclovir should be considered.


  • most common complication is secondary infection of lesions
    • Rare complications include
      • pneumonia
      • encephalitis (cerebella involvement may be seen)
      • Disseminated haemorrhagic chickenpox
      • arthritis, nephritis and pancreatitis may be seen very rarely.