|

Chickenpox in Children

Last updated:

Overview

Chickenpox describes a primary, acute infection caused by the varicella-zoster virus (VZV) characterised by an itchy vesicular rash.

Shingles describes the reactivation of VZV and is known as herpes zoster. After a chickenpox infection, VZV can remain dormant in the dorsal root or cranial nerve ganglia. Over time, as the immune system becomes less effective at suppressing VZV, it reactivates, leading to shingles.

Exposure to chickenpox in childhood leads to lifelong IgG antibodies which persist for life.

Transmission

Chickenpox is:

  • Highly infectious and around 90% of susceptible close contacts develop it
  • Spread by respiratory droplets or direct contact with skin lesions
  • Infectious from 24 hours before the rash appears until the vesicles are dry and have crusted over (usually 5 days)

It has an incubation period of 1-3 weeks and it is possible for chickenpox reinfection, but uncommon.

Epidemiology

  • Chickenpox is predominantly a childhood illness
  • More than 90% of people >15 years old are immune

Presentation

The typical features of chickenpox include:

  • A febrile prodrome:
    • May have nausea, myalgia, anorexia, headaches, malaise
  • Followed by an itchy rash:
    • First, small, erythematous macules appear on the head and trunk before spreading
    • They then become papules, vesicles, and itchy pustules
    • Crusting usually occurs within 5 days of the rash onset and crusts fall off after 1-2 weeks

Investigations

Overview

Laboratory tests are rarely required in primary care unless exposure to chickenpox has occurred in at-risk groups. 

Management

Overview

  • 1stline: supportive treatment
    • Paracetamol, topical calamine lotion
  • School exclusion:
    • Children should be kept away from school or nursery until all vesicles have crusted over (around 5 days after the onset of the rash)
  • Safety-net:
    • Patients should return if they deteriorate or if features of complications occur including bacterial superinfection or dehydration
  • Avoid contact with pregnant and immunocompromised people

Complications

Complications in children

  • Bacterial superinfection – a secondary bacterial infection superimposed on chickenpox:
    • Most commonly caused by Group A Streptococcus (e.g. Streptococcus pyogenes) and Staphylococcus aureus
    • Presents with sudden high-grade fever (often after initial improvement), erythema, and tenderness around the original chickenpox lesions
    • May lead to impetigo, cellulitis, erysipelas, necrotising fasciitis, and scarring
    • The use of NSAIDs may increase this risk
  • Rare complications include:
    • Pneumonia
    • Neurological complications:
    • Disseminated haemorrhagic chickenpox
    • Glomerulonephritis
    • Henoch–Schönlein purpura
    • Pancreatitis
    • Keratitis

Prognosis

  • In most cases, chickenpox is self-limiting and relatively mild
  • Severe disease and complications are more likely to occur in children aged <1 year old, adults, pregnant women, and immunocompromised people
  • Recovery from a primary chickenpox infection usually leads to lifelong immunity, however, chickenpox recurrence in health people has been reported, but uncommon
    • This is more likely to occur in people who are immunocompromised

Author