Summary
Definition
History and exam
Key diagnostic factors
- acute onset
- airway swelling (angio-oedema)
- inspiratory stridor and hoarse voice
- shortness of breath
- wheezing, chest hyperinflation, and accessory muscle use
- cyanosis
- respiratory arrest
- pale, clammy skin
- hypotension
- increased pulse rate (tachycardia)
- bradycardia
- cardiac arrest
- confusion or disorientation
- urticaria (hives)
- erythema
- pruritus
- angio-oedema
- rhinitis
- bilateral conjunctivitis
Other diagnostic factors
- risk factors
- nausea, vomiting, diarrhoea, and incontinence
- abdominal cramps and pain
- agitation, anxiety, and a sense of impending doom (angor animi)
Risk factors
- adult age: food-, insect venom- and medicine-related
- <30 years old: food-associated, exercise-induced
- female sex
- atopy/asthma
- history of anaphylaxis
- exposure to a common sensitiser (e.g., latex)
Diagnostic investigations
1st investigations to order
- mast cell tryptase
- 12-lead ECG
- urea and electrolytes
- arterial blood gases
Investigations to consider
- chest x-ray
Treatment algorithm
presumed anaphylaxis: in cardiorespiratory arrest
presumed anaphylaxis: not in cardiorespiratory arrest
after initial treatment: not in cardiorespiratory arrest
post-anaphylaxis
Contributors
Expert advisers
Alexander Alexiou, MB BS BSc DCH FRCEM Dip IMC RCSEd
Emergency Medicine Consultant
Barts Health NHS Trust
Physician Response Unit Consultant
London’s Air Ambulance
Royal London Hospital
London
UK
Disclosures
AA declares that he has no competing interests.
Thomas Palmer, BSc MBChB FRCEM
ST6 Emergency Medicine
Royal London Hospital
London
UK
Disclosures
TP declares that he has no competing interests.
Acknowledgements
BMJ Best Practice would like to gratefully acknowledge the previous team of expert contributors, whose work has been retained in parts of the content:
Doerthe Adriana Andreae MD
Assistant Professor
Pediatric Allergy and Immunology
Penn State Health Milton S. Hershey Medical Center
Hershey
PA
Michael Henning Andreae MD
Associate Professor
Department of Anesthesiology
Penn State Health Milton S. Hershey Medical Center
Hershey
PA
Disclosures
DAA is author of an UpToDate article on food allergy and a number of references cited in this topic. MHA is an author of a reference cited in this topic.
Peer reviewers
Robert Taylor, MBChB MRCP(UK) MRCP(London) DipMedTox DipTher PGDME FHEA FRCEM
Acute Hospital Sub Dean (Cornwall)
Honorary Clinical Senior Lecturer
Consultant Emergency Physician
The Knowledge Spa
Royal Cornwall Hospital
Truro
UK
Disclosures
RT declares that he has no competing interests.
Editors
Celia Pincus
Section Editor, BMJ Best Practice
Disclosures
CP declares that she has no competing interests.
Susan Mayor
Lead Section Editor, BMJ Best Practice
Disclosures
SM works as a freelance medical journalist and editor, video editorial director and presenter, and communications trainer. In this capacity, she has been paid, and continues to be paid, by a wide range of organisations for providing these skills on a professional basis. These include: NHS organisations, including the National Institute for Health and Care Excellence, NHS Choices, NHS Kidney Care, and others; publishers and medical education companies, including the BMJ Group, the Lancet group, Medscape, and others; professional organisations, including the British Thoracic Oncology Group, the European Society for Medical Oncology, the National Confidential Enquiry into Patient Outcome and Death, and others; charities and patients’ organisations, including the Roy Castle Lung Cancer Foundation and others; pharmaceutical companies, including Bayer, Boehringer Ingelheim, Novartis, and others; and communications agencies, including Publicis, Red Healthcare and others. She has no stock options or shares in any pharmaceutical or healthcare companies; however, she invests in a personal pension, which may invest in these types of companies. She is managing director of Susan Mayor Limited, the company name under which she provides medical writing and communications services.
Rachel Wheeler
Lead Section Editor, BMJ Best Practice
Disclosures
RW declares that she has no competing interests.
Julie Costello
Comorbidities Editor, BMJ Best Practice
Disclosures
JC declares that she has no competing interests.
Adam Mitchell
Drug Editor, BMJ Best Practice
Disclosures
AM declares that he has no competing interests.
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