May 2026 exceptional surveillance of anaphylaxis: assessment and referral after emergency treatment (NICE guideline CG134)
Addendum – Updating NICE's guideline with the RCUK's recommendations about post-anaphylaxis observation periods
Introduction
This surveillance report's proposal to replace NICE's guideline recommendations about post-anaphylaxis observation periods in adults aged 16 years and older and children with the RCUK's recommendations about a risk-stratified approach to the length of in-hospital observation following anaphylaxis was approved in July 2025. Risk-stratified recommendations as recommended by the RCUK were assessed by NICE as having the potential to improve patient care by ensuring that people are not unnecessarily detained while those at greater risk of biphasic reaction (BR) are observed for a safe duration of time. They were also assessed as having the potential to be cost saving for the NHS by freeing up emergency department capacity.
As the proposed wording of new recommendations was to be based on RCUK recommendations with clarifications agreed with an RCUK topic expert, the update was carried out by NICE's surveillance team and publishing team without the need of a full evidence review. Work began in August 2025.
Update methods
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Working closely with a topic expert at the RCUK, who is part of the RCUK's anaphylaxis working group and co-author of the RCUK's emergency treatment of anaphylactic reactions, to approve adapted wording and clarify RCUK recommendations as required.
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Consulting with a NICE CCA with expertise in the management of anaphylaxis about additions and amendments to NICE's guideline.
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Working with a NICE senior guidance content designer to ensure new recommendations are coherent with existing recommendations and meet with NICE's writing and presentational standards.
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Consulting with NICE's guideline stakeholders about all substantive changes to the guideline (see stakeholder consultation).
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Sign-off on the recommendations for publication after consideration by NICE's Guideline Executive.
The areas updated
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Recommendations 1.1.7 to 1.1.10 have been added. These are adapted from the RCUK's guidance and recommend a risk-stratified approach to the duration of the period of observation following treatment for suspected anaphylaxis in the emergency setting prior to discharge. They apply to all age groups.
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Recommendation 1.1.11 has been created which recommends admitting children aged less than 16 years if they cannot be discharged after 2 hours of observation in accordance with the criteria in recommendation 1.1.7. This is to ensure children access the most appropriate care pathway if a longer period of observation is required.
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Recommendations 1.1.15 and 1.1.16 have been updated and restructured to make it clear that at discharge, prescribers should offer 2 in-date adrenaline auto-injectors (AAIs), with a brand-specific demonstration of their use and advice to always carry them, in line with MHRA and RCUK guidance.
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Recommendation 1.1.15 has also been updated to recommend not offering AAIs to patients with anaphylaxis resulting from a drug allergy, where the drug has been identified and can be subsequently easily avoided. This is to align NICE's guideline with RCUK and BSACI (British Society for Allergy & Clinical Immunology) guidance.
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The use of 'anaphylaxis' has been used in place of 'anaphylactic reaction' throughout the recommendations in line with current best practice.
Stakeholder consultation
We carried out a 2 week consultation on the draft recommendations, which focussed on substantive changes. Full stakeholder questions, their comments and our responses can be seen in appendix A, but in brief we received 8 responses from the following organisations: RCUK, Royal College of Anaesthetists, General College of Dentistry, South Eastern Health and Social Care Trust, Royal College of Pathologists, Association of Paediatric Emergency Medicine, British Paediatric Allergy, Immunity and Infection Group, and NHS England.
We asked 4 questions about the substantive changes to NICE's guideline and 1 question about whether there was any health inequalities associated with anaphylaxis that NICE's guideline could better address. There was strong support from stakeholders for NICE's guideline adopting the RCUK's recommendations (7 agreed, and 1 thought 6 to 12 hours of observation was adequate) about post-anaphylaxis observation periods. Stakeholders welcomed the consistency with the RCUK guidance.
There was also strong support for amending discharge recommendations to make it clearer that 2 AAIs should be offered to people who need it prior to discharge and that this was not needed in cases of a drug-induced anaphylaxis where the drug allergen was known and could be subsequently easily avoided; 7 stakeholders agreed and 1 disagreed. The latter noted the provision of AAIs may be difficult for smaller services out of hours. No stakeholder disagreed with the update to not offer AAIs in cases of drug-induced anaphylaxis where the drug can be easily avoided.
There were several suggestions made by stakeholders about the wording and structure of the recommendations that improved their clarity and which we adopted, briefly these were:
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2 stakeholders commented that not all children require admission following treatment for suspected anaphylaxis. They commented that many families are experienced in dealing with the post-anaphylaxis period following resolution of symptoms after treatment, and the appropriate period of in-hospital observation. We amended recommendation 1.1.7 to say only those children who could not be discharged after 2 hours of observation should be admitted based on these responses, and on comments from a NICE clinical colleague with anaphylaxis expertise.
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We added the word 'when' to recommendation 1.1.7 bullet 3 based on stakeholder feedback, for example, 'the person already has 2 in-date adrenaline auto-injectors and knows how and when to use them.'
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Stakeholders highlighted that the 2011 version of NICE's guideline was confusing and unclear with respect to the number of AAIs that should be offered to patients. They noted that NICE's guideline seemed to be suggesting a clinician should offer 3 AAIs. Offering 2 AAIs is in line with current MHRA guidance. We amended recommendation 1.1.15 to make it explicit that patients should be offered 2 AAIs before discharge.
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Stakeholders commented that intranasal adrenaline (EURNeffy) has been licensed for people weighing 30 kg or more and that recommendations should be amended to reflect this event. EURNeffy licensing was also raised by RCUK colleagues, however, currently there is limited evidence for EURNeffy's effectiveness. We are tracking an ongoing trial about EURNeffy which we will assess when it publishes, and we will continue to monitor for other emerging evidence about intranasal adrenaline. We have also highlighted this area to the NIHR.
Conclusion
NICE's Guideline Executive agreed publication of the updated recommendations. In addition, for final publication, it was decided that the changes were substantive enough to warrant replacing NICE's existing guideline (CG134) with the new NICE guideline (NG258).
ISBN: 978-1-4731-9534-9
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