Anaphylaxis is a severe, life-threatening generalised or systemic hypersensitivity, affecting the whole body, often within minutes of exposure to a trigger substance. This reaction affects the airways (oedema), breathing (bronchospasm with tachypnoea) and circulation (hypotension and/or tachycardia).
Although patients with severe allergic reactions only occasionally present to GPs, primary care clinicians can play a vital part in supporting these patients as well as providing continuing management and review of their condition, offering opportunities to recognise comorbidities.
|Advice following an episode of anaphylaxis|
Management of an anaphylactic episode is detailed in the Resuscitation Council guidelines.1 In 2012, NICE produced guidance on how to manage the patient with suspected anaphylaxis.2 This guideline followed the 2011 NICE guideline on food allergy3 and the Royal College of Paediatrics and Child Health (RCPCH) pathway on allergic disease in childhood.4
NICE guidelines2 recommend that children aged under 16 years should be admitted to hospital under the care of a paediatric medical team, while patients over the age of 16 years should be observed for six to 12 hours from the onset of symptoms. With appropriate post-reaction care, those reactions that were controlled promptly and easily may be observed for a shorter period.
Patients presenting with severe allergic reactions should therefore be assessed by secondary care providers, rather than managed in the community. Patients should be referred to a specialist allergy service and provided an appropriate adrenaline injector as part of the secondary care management process.2
Primary care providers should be aware of this, ideally reviewing patients on receiving a discharge letter or communication from A&E. It is essential that primary and secondary care work together and communicate to ensure effective patient care pathways can be followed.
While GPs would be expected to ensure immediate hospital attendance for any severe acute presentations, the NICE guideline on food allergy3 recommends that referral to secondary care should include patients with acute systemic reactions or severe delayed reactions, faltering growth and GI symptoms, significant atopic eczema with suspicion of multiple food allergies and those with possible multiple food allergies. The foods most commonly causing reactions are milk, eggs, peanuts and shellfish.
Serum specific IgE and skin prick tests tell you only if a patient is sensitised, meaning that the immune system is capable of producing a response to the substance. Results do not indicate the severity of future reactions. Testing cannot be used to 'screen' patients with no allergy history. It is considered that 80% of patients who are sensitised to peanut will not experience symptoms on exposure.5 A positive result should confirm the relevance of the specific trigger to that patient. A positive result alone is meaningless.
NICE suggests testing children for one specific food when an IgE reaction is suspected to that food. Following testing, NICE suggests referral if there is a proven IgE reaction and asthma, negative test results but a history giving clinical suspicion of IgE-mediated allergy or persisting parental suspicion of food allergy but unconvincing history.3 Severe venom reactions should be referred to an allergy centre.
Training and best practice
Primary care has a vital role in the management of allergies and anaphylaxis. The Anaphylaxis Campaign has designed online training to provide those in general practice with the knowledge needed to support patients affected by severe allergies.
- Dr Walsh is a GP partner in Norwich, Norfolk, and member of the Clinical and Scientific Panel of the Anaphylaxis Council
1. Resuscitation Council UK. Guidelines on emergency treatment of anaphylactic reactions. January 2008 www.resus.org.uk/pages/reaction.pdf
2. NICE. Guidance on initial assessment and referral following emergency treatment for an anaphylactic episode. CG134. London, NICE, December 2011. http://guidance.nice.org.uk/CG134
3. NICE. Guidance on the diagnosis and assessment of food allergy in children and young people in primary care and community settings. CG116. London, NICE, February 2011. http://guidance.nice.org.uk/CG116
4. RCPCH. Allergy care pathways for children. Food allergy. RCPCH 2011 www.rcpch.ac.uk/allergy/foodallergy
5. Nicolau N, Poorafshar M, Murray C et al. Allergy or tolerance in children sensitized to peanut: prevalence and differentiation using component-resolved diagnostics. J Allergy Clin Immunol 2010; 125: 191-197.e13.