Last reviewed: 1 Nov 2021
Last updated: 29 Sep 2021



History and exam

Key diagnostic factors

  • presence of risk factors
  • fever
  • vesicular rash
  • vesicles on mucous membranes

Other diagnostic factors

  • pruritus
  • headache
  • fatigue/malaise
  • sore throat
  • tachycardia

Risk factors

  • exposure to varicella
  • age 1 to 9 years
  • unimmunised status
  • occupational exposure

Diagnostic investigations

Investigations to consider

  • polymerase chain reaction
  • viral culture
  • direct fluorescent antibody testing (DFA)
  • Tzanck smear
  • latex agglutination (LA)
  • enzyme-linked immunosorbent assay (ELISA)
  • complement fixation
  • ultrasound (pregnant women)

Treatment algorithm



Andrew Riordan, MD, FRCPCH, MRCP, DTM&H

Consultant in Paediatric Infectious Diseases and Immunology

Royal Liverpool Children's Hospital (Alder Hey)




AR declares that he has no competing interests.


Dr Andrew Riordan would like to gratefully acknowledge Dr Steven Pergam, Dr Rupali Jain, and Dr Anna Wald, previous contributors to this topic.


SP has served as a consultant for Merck & Co., Inc, Optimer/Cubist, and Chimerix, and has participated in clinical trials with these three organizations. He is also an author of a paper cited in this topic. RJ declares that she has no competing interests. AW is a member of the Data and Safety Monitoring Board (DSMB) for a Merck study of a candidate VZV vaccine.

Peer reviewers

Chad M. Hivnor, Major, USAF, MC, FS


Outpatient & Pediatric Dermatology

59th Medical Wing/ SGOMD

Lackland Air Force Base

San Antonio



CMH declares that he has no competing interests.

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