Anaphylaxis is a severe and potentially life-threatening condition that is becoming increasingly prevalent. Healthcare professionals working in a variety of settings must know how to recognise this condition and the importance of treating it promptly. 

Article by Nikki Welyczko

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Anaphylaxis is defined as, 'A serious systemic hypersensitivity reaction that is usually rapid in onset and may cause death' (Cardona et al, 2020).

There are approximately 20–30 deaths reported each year as a result of anaphylaxis in the UK (Resuscitation Council UK, 2021). There were nearly 26 000 admissions in 2022–23 (25 721 admissions), for allergy or anaphylaxis more than double the 12 361 admissions in 2002–03 (a 108% increase) (Medicines and Healthcare products Regulatory Agency (MHRA), 2023).

For food-related anaphylaxis and other adverse reactions, the rise is even higher, going from just under 2000 admissions in 1971 to just over 5000 last year (a 154% increase) (MHRA, 2023). Approximately 10 deaths a year are related to food-induced anaphylaxis (Harper et al, 2018).

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Symptoms and diagnosis

Anaphylaxis is characterised by rapidly developing, life-threatening problems involving:

  • the airway (pharyngeal or laryngeal oedema) 
  • breathing (bronchospasm with tachypnoea) 
  • circulation (hypotension and/or tachycardia)

In most cases, there are associated skin and mucosal changes, such as flushing, urticaria and angioedema (National Institute for Health and Care Excellence (NICE), 2021). However, cutaneous symptoms are absent in 10–20% of cases (Muraro et al, 2014; Resuscitation Council UK, 2021).

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Anaphylaxis can be caused by a broad range of triggers, but the most common allergens identified include food, drugs and venom (Turner et al, 2015) (Table 1).

Food is the most common cause of anaphylaxis, accounting for 30% of all cases (Resuscitation Council UK, 2021). Young people are at greater risk of food-related anaphylaxis (Resuscitation Council UK, 2021). Pre-school aged children have the highest rate of hospitalisation from food-related anaphylaxis, but fatalities in this age group are low (Resuscitation Council UK, 2021). Teenagers and adults up to the age of 30 years have the greatest risk of fatal food allergies (Conrado et al, 2021; Turner et al, 2015).

Drug-related anaphylaxis is rare in children, and is highest in the elderly (Turner et al, 2015).


Table 1. Common causes of anaphylaxis (non-fatal and fatal) in the UK 


Anaphylaxis (all severities)

Fatal anaphylaxis


Most common triggers:

• Peanut

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Prompt assessment and management are essential, as delays in treatment are associated with fatal outcomes (Anagnostou and Turner, 2019). Many patients with anaphylaxis are not given the correct treatment because of failure to recognise anaphylaxis (Lindor et al, 2018). The key steps for the initial treatment of anaphylaxis are outlined in the Resuscitation Council UK (2021) Emergency Treatment of Anaphylaxis guidelines, summarised below, and are applicable to all healthcare settings:

  • Triage any allergic reaction with urgency as patients are at risk of rapid deterioration with the development of anaphylaxis, if not already anaphylactic (De Feo et al, 2018; Cohen et al, 2018)
  • Assess and treat the patient’s airway, breathing, circulation, disability and exposure (Resuscitation Council UK, 2021)
  • Airway management is critical. Assess the patient’s airway for patency and identify risks such as a hoarse voice, perioral oedema, stridor and angioedema (McLendon and Sternard, 2023)
  • Get help – call for a

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NMC proficiencies

Nursing and Midwifery Council: standards of proficiency for registered nurses

Part 1: Procedures for assessing people’s needs for person-centred care

1. Use evidence-based, best practice approaches to take a history, observe, recognise and accurately assess people of all ages

2.16 recognise and manage seizures, choking and anaphylaxis, providing appropriate basic life support

Part 2: Procedures for the planning, provision and management of person-centred nursing care

11. Procedural competencies required for best practice, evidence-based medicines administration and optimisation

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Anagnostou K, Turner PJ. Myths, facts and controversies in the diagnosis and management of anaphylaxis. Arch Dis Child. 2019;104(1):83-90. http://doi.org/10.1136/archdischild-2018-314867

Conrado AB, Ierodiakonou D, Gowland MH. Food anaphylaxis in the United Kingdom: analysis of national data, 1998-2018BMJ. 2021;372:n251. https://doi.org/10.1136/bmj.n251

Cardona V, Ansotegui IJ, Ebisawa M et al. World allergy organization anaphylaxis guidance 2020. World allergy organisation journal. 2020;13(10):100472. https://doi.org/10.1016/j.waojou.2020.100472

Cohen N, Capua T, Pinko D et al. Trends in the diagnosis and management of anaphylaxis in a tertiary care pediatric emergency departmentAnn Allergy Asthma Immunol. 2018;121(3):348-352. https://doi.org/10.1016/j.anai.2018.06.033

De Feo G, Parente R, Triggiani M. Pitfalls in anaphylaxis. Curr Opin Allergy Clin Immunol. 2018;18(5):382-386. https://doi.org/10.1097/ACI.0000000000000468

Dodd A, Hughes A, Sargant N et al. Evidence update for the treatment of anaphylaxis. Resuscitation. 2021;163:86-96. https://doi.org/10.1016/j.resuscitation.2021.04.010

Ewan PW. Adverse reactions to colloids. Anaesthesia. 2001;56(8):771-772. https://doi.org/10.1046/j.1365-2044.2001.01916-3.x

Grammar LC. Idiopathic Anaphylaxis. 2023. https://www.uptodate.com/contents/idiopathic-anaphylaxis (accessed 6 December 2023)

Harper NJN, Cook TM, Garcez T et al. Anaesthesia, surgery, and life-threatening allergic reactions: epidemiology and clinical features of perioperative anaphylaxis in the 6th National Audit Project (NAP6)

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