Acute varicella-zoster

Last reviewed: 22 Aug 2023
Last updated: 19 Apr 2023



History and exam

Key diagnostic factors

  • history of exposure
  • fever
  • vesicular rash
  • vesicles on mucous membranes
More key diagnostic factors

Other diagnostic factors

  • pruritus
  • headache
  • fatigue/malaise
  • sore throat
  • tachycardia
Other diagnostic factors

Risk factors

  • exposure to varicella
  • age 1 to 9 years
  • unvaccinated status
  • occupational exposure
More risk factors

Diagnostic investigations

1st investigations to order

  • clinical diagnosis
More 1st investigations to order

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)
More investigations to consider

Treatment algorithm


otherwise healthy children at low risk of severe disease

increased risk of moderate to severe disease

high risk of severe disease

severe disease



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.

  • Acute varicella-zoster images
  • Differentials

    • Smallpox
    • Herpes zoster infection (shingles)
    • Herpes simplex virus (HSV) infection
    More Differentials
  • Guidelines

    • Recommended adult immunization schedule for ages 19 years or older, United States, 2023
    • Recommended child and adolescent immunization schedules for ages 18 years or younger, United States, 2023​
    More Guidelines
  • Patient leaflets


    Chickenpox vaccine

    More Patient leaflets
  • padlock-lockedLog in or subscribe to access all of BMJ Best Practice

Use of this content is subject to our disclaimer