You are here

Chickenpox A004

Document
Last amended 
8 May 2023
Current RMA Instruments
Reasonable Hypothesis SOP29 of 2023
Balance of Probabilities SOP 30 of 2023
Changes from previous instruments

SOP Bulletin 236

 ICD Coding

ICD-10-AM Code: B01

Brief description

Chickenpox is an acute self-limiting viral infection by the Varicella-Zoster virus.  It manifests as a vesicular skin rash but can also produce systemic effects which can be serious such as pneumonia, or encephalitis.  The incubation period is between 10-21 days.  The virus is highly contagious.  Infectivity is generally considered to last from 48 hours prior to the onset of the rash until the skin lesions have fully crusted.  The condition can be more severe if contracted as an adult rather than as a child.

The reactivation of a quiescent latent infection is ‘Shingles’ and is this covered by a separate SOP.  A claim of chicken pox should generally be determined as “Chicken pox – resolved”.

Confirming the diagnosis:

The diagnosis is typically made clinically, but can be confirmed by testing the vesicular fluid, or by serology.

The relevant medical specialist is an infectious disease physician.

Additional diagnoses covered by these SOPs
  • Varicella
Conditions not covered by these SOPs   
  • Herpes zoster*
  • Shingles (and postherpetic neuralgia)*       

* another SOP applies 

Clinical onset

The clinical onset will be when the first symptoms, subsequently confirmed to be due to chickenpox, developed.  

Clinical worsening

There are no worsening factors except for inability to obtain appropriate clinical management.  Treatment is usually symptomatic only unless the patient is immunocompromised, or complications develop.  If clinical worsening is being considered an opinion from an infectious disease physician should be sought, on whether there has been a clinical worsening out of keeping with the natural history of the underlying pathology.