Chickenpox

Chickenpox is a highly infectious, acute contagious disease predominantly of children under 10 years old, though it may occur at any age. It is characterised by fever and a rash, and is caused by varicella zoster virus.

The name chickenpox is said to relate to the similarity of the skin lesions to boiled chick-peas.

Around 90% of people who come into contact will develop the disease.

Transmission is through

• direct person to person contact
• airborne droplet infection
• through contact with infected articles such as clothing and bedding

Around 90% of adults over the age of 18 years have immunity for VZV in the UK. Although not seen in recent years, varicella infections occurs in a seasonal pattern with a peak incidence from March to May.

Reactivation of latent VZV will result in shingles (herpes zoster) which is more likely to be seen in adults.

A person exposed to shingles may develop Chicken pox but a person exposed to Chicken pox will not develop Shingles.

Click here for an example image of this condition

Key points:

• pregnant/immunocompromised/ neonate:
  • seek urgent specialist advice
• chickenpox:
  • consider aciclovir if:
    • onset of rash <24 hours, and 1 of the following:
      • >14 years of age;
      • severe pain;
      • dense/oral rash;
      • taking steroids;
      • smoker
  • give paracetamol for pain relief

Reference:

1. UK Health Security Agency. The Green Book: Varicella. Jun 2019 [internet publication].
2. Freer G, Pistello M. Varicella-zoster virus infection: natural history, clinical manifestations, immunity and current and future vaccination strategies. New Microbiol. 2018 Apr;41(2):95-105.