Anaphylaxis

Last reviewed: 3 Sep 2022
Last updated: 03 Nov 2020

Summary

Definition

History and exam

Key diagnostic factors

  • acute onset
  • urticaria
  • angioedema
  • flushing
  • dyspnea
  • wheezing
  • rhinitis
More key diagnostic factors

Other diagnostic factors

  • allergen ingestion
  • insect stings or bites
  • pruritus
  • inspiratory stridor and hoarse voice
  • bilateral conjunctivitis
  • nausea and vomiting
  • abdominal cramping or pain
  • agitation/anxiety
  • confusion/disorientation
  • tachycardia
  • dizziness
  • syncope
  • sense of impending doom (angor animi)
  • recent exercise
  • hot or cold exposure
  • hypotension
  • bradycardia
  • cardiac arrest
  • diarrhea
  • visual disturbances
  • tremor
  • seizures
Other diagnostic factors

Risk factors

  • adult age: food-, insect venom-, and medication-related
  • <30 years old: food-associated, exercise-induced
  • female sex
  • atopy/asthma
  • history of anaphylaxis
  • exposure to a common sensitizer (e.g., latex)
More risk factors

Diagnostic investigations

1st investigations to order

  • serum tryptase level
More 1st investigations to order

Investigations to consider

  • in vitro IgE testing
  • skin test
  • challenge test
More investigations to consider

Emerging tests

  • basophil activation test

Treatment algorithm

INITIAL

all patients: acute onset

ONGOING

patients with identified allergen

Contributors

Authors

Doerthe Adriana Andreae, MD

Assistant Professor

Pediatric Allergy and Immunology

Penn State Health Milton S. Hershey Medical Center

Hershey

PA

Disclosures

DAA is author of an UpToDate article on food allergy, for which she receives royalties. DAA is an author of a number of references cited in this topic.

Michael Henning Andreae, MD

Associate Professor

Department of Anesthesiology

Penn State Health Milton S. Hershey Medical Center

Hershey

PA

Disclosures

MHA is an author of a reference cited in this topic.

Acknowledgements

Dr Doerthe Adriana Andreae and Dr Michael Henning Andreae would like to gratefully acknowledge Dr Andrea Vereda, a previous contributor to this topic.

Disclosures

AV declares that she is currently employed by Aimmune Therapeutics. AV wrote the main content of this topic before taking up this appointment.

Peer reviewers

Frank J. Domino, MD

Associate Professor

Family Medicine and Community Health

University of Massachusetts Medical School

Worcester

MA

Disclosures

FJD declares that he has no competing interests.

Wayne Shreffler, MD, PhD

Assistant Professor of Pediatrics

Mount Sinai School of Medicine

New York

NY

Disclosures

WS declares that he has no competing interests.

Lawrence Youlten, FRCP (Edin), PhD

Visiting Consultant in Allergy

Addenbrooke’s Hospital NHS Trust

Cambridge

UK

Disclosures

LY declares that he has no competing interests.

Grant Hayman, MBChB, MRCP, DTM and H, MSc, FRCPath

Consultant Immunologist

Department of Immunology

Epsom & St Helier University Hospitals NHS Trust

Carshalton

Surrey

UK

Disclosures

GH declares that he has no competing interests.

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