NICE on anaphylaxis

With thanks to my colleague, Dr Su Li, for summarising this 2011 NICE guideline for Paediatric Pearls.

Anaphylaxis: assessment to confirm an anaphylactic episode and the decision to refer after emergency treatment for a suspected anaphylactic episode

December 2011

Anaphylaxis is a severe, life-threatening, generalised hypersensitivity reaction involving

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


There can often be skin and mucosal changes. Patients presenting with these signs and symptoms should be diagnosed as having ‘suspected anaphylaxis’.

Anaphylaxis may be an allergic response that is

  • immunologically IgE mediated (foods, venoms, drugs, latex) or
  • non-immunologically mediated or
  • idiopathic (significant clinical effects with no obvious cause).


This guideline does not make any drug recommendations. These can be found at

Patient Centred Care

  • Treatment and care should take into account patient’s needs and preferences
  • Patients should have the opportunity to make informed decisions about their care and treatment, in partnership with health care professionals
  • Good communication between healthcare professionals and patients is essential
  • Families and carers should be given the information and support they need
  • Care of young people in transition between paediatric and adult services should be planned and managed according to the best practice guidance described in ‘Transition: getting it right for young people



  • Document acute clinical features of the suspected anaphylaxis
  • Record the time of onset
  • Record the circumstances immediately before the onset of symptoms to help identify possible triggers


  • Consider taking blood samples for mast cell tryptase if reaction is thought to be immunologically mediated or idiopathic
    • First sample as soon after emergency treatment given
    • Second sample 1-2 hours (no more than 4 hours) from onset of symptoms
    • A further sample may be required at follow up with the allergy specialist to measure baseline mast cell tryptase


  • Children who have had emergency treatment should be admitted to hospital under the care of the paediatric team.  The resus council suggests observing the child for a pragmatic (no evidence yet) 6 hours because of the risk of a biphasic reaction.
  • Offer the child/parents a referral to an allergy specialist (see for registered allergy clinics)
  • Offer the child/parents an adrenaline injector in the interim period whilst waiting for a specialist appointment


  • Before discharge, offer the child/parents
    • Information about anaphylaxis (signs, symptoms, risk of recurrence of symptoms (biphasic reaction)).  Parent information leaflet here.
    • Information about what to do if a reaction occurs (use adrenaline injector, call emergency services)
    • Demonstration on how to use an adrenaline injector see for a clear American description of how to use it.
    • Advice about how to avoid potential triggers
    • Information about the need for referral and the referral process to an allergy specialist
    • Information about patient support groups


Research Recommendations

  • Mast cell tryptase is not always elevated in children, particularly if food is thought to be the allergen or if respiratory compromise is the main clinical feature. It is recommended that further studies be carried out to identify other potential chemical inflammatory mediators.
  • There is limited evidence on biphasic reactions. Follow up studies are recommended.
  • There are no studies on length of observation period following emergency treatment for suspected anaphylaxis
  • There is limited data on the annual incidence or anaphylactic reactions and their associated outcomes.
  • The Guideline Development Group feel that referral to specialist services and/or the provision of adrenaline injectors are likely to benefit patients who have experienced a suspected anaphylaxis as a result of decreased anxiety and ongoing support. This benefit is yet to be quantified.

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