A primary care nurse’s quick guide to…
Peanut allergy and anaphylaxis
Key learning points:
1. Allergy to peanuts is the most common food allergy, and can cause potentially fatal anaphylactic reactions
2. Primary care nurses should be able to spot signs and symptoms and take key steps towards diagnosis
3. Management is based on allergen avoidance and emergency response; nurses can play a key role in advice and education
A holy trinity of factors makes peanut allergy the perfect fodder for newspaper headlines: prevalence in children; ubiquity of the foodstuff; potentially fatal consequences. Thus developments in peanut allergy invariably generate a host of headlines. The finding – published in March – that early introduction of peanut protects against the development of peanut allergy, and that this protection is sustained even when peanut is no longer consumed for 12 months, is just the latest example.1
Those headlines in turn generate a host of questions from patients, anxious parents and carers, and expectant mothers. Primary care professionals are first in the firing line for those questions so here’s a quick guide to help you answer them and to identify, manage and refer patients appropriately.
What is peanut allergy and anaphylaxis?
A food allergy is an adverse immune response to a food.2 Peanut allergy is the most common: its prevalence has increased in western countries, and it is now estimated to affect 1-2% of children in the UK.3,4
As with any allergy, a reaction to peanuts can be mild; however, it is the most common cause of fatal allergic reactions involving food. In one study, allergies to peanut (a member of the legume, or bean, family) accounted for 55% of fatal anaphylactic food reactions.5
Anaphylaxis is a severe hypersensitivity reaction characterised by rapidly developing, life-threatening symptoms involving the airway, breathing and/or circulation. The National Institute for Health and Care Excellence (NICE) cites figures that suggest 220,000 people up to the age of 44 in the UK have had a nut-induced (including peanut) anaphylactic reaction. NICE suggests that the estimated 20 people in the country each year who die from all-cause anaphylaxis ‘may be an underestimate’.6
Most NHS allergy care takes place in primary care,2 therefore the identification, diagnosis and management of peanut allergy is particularly relevant for primary care nurses.
Anaphylaxis is more of a secondary care concern; but recognising its signs and symptoms is paramount for all, and primary care practitioners can educate patients and carers to do so and to seek prompt help.
Spotting the signs and symptoms
The NICE quality standard on food allergy published in March this year states that service providers must ‘ensure that healthcare professionals can recognise the signs and symptoms of food allergy… and can take an allergy‑focused clinical history’.7
It further advises that ‘nurses with training and skills in allergy… recognise the signs and symptoms of food allergy… and take an allergy‑focused clinical history as a key step towards diagnosis’.7
The signs and symptoms that should alert a nurse to the possibility of food allergy are listed in the NICE guideline Food allergy in under 19s: assessment and diagnosis, as in the table below.2They are categorised into symptoms that suggest an allergic reaction caused by the production of IgE antibodies (acute with rapid onset), versus those that suggest a non-IgE-mediated allergic reaction (delayed and non-acute). The mechanism for the latter is poorly understood but likely to be mediated by T-cells.7
acute angiodema, most commonly lips, face and eyes
angiodema of lips, tongue and palate
loose or frequent stools
stools containing blood or mucus
colicky abdominal pain
food refusal or aversion
pallor and tiredness
faltering growth in conjunction with at least one or more GI symptoms above (referral to secondary care should be considered)
Usually in conjunction with at least one of the above symptoms
Upper respiratory tract symptoms (nasal itching, sneezing, rhinorrhoea or congestion)
Lower respiratory tract symptoms (cough, chest tightness, wheezing or shortness of breath)
Signs or symptoms of anaphylaxis (characterised by rapidly developing, life-threatening symptoms involving the airway, breathing and/or circulation) or other systemic allergic reactions
Diagnosing peanut allergy
March’s NICE quality standard on food allergy sets out the areas to cover in an allergy-focused clinical history, which includes:
• The suspected allergen, and how it came to be so.
• Details of the presenting and other symptoms, such as onset, severity, duration and frequency.
• Feeding and diet history, including religious and cultural factors.
• Personal and family history of atopic diseases.7
Patients whose history suggests an IgE-mediated allergy should be offered skin-prick or blood tests to confirm this, in primary care if there is appropriate expertise and facilities (notably for dealing with anaphylaxis) or by referral.7
Those whose history suggests a non-IgE-mediated allergy should be offered a trial elimination and subsequent reintroduction of the suspected allergen (not in the case of severe delayed reactions, when patients should be referred). NICE recommends that ‘healthcare professionals should have a good understanding of nutritional intake, timings of elimination and reintroduction, and follow‑up’.7
The under-19s guideline sets out further scenarios in which to consider referral, including: suspicion of multiple allergens; previous acute systemic reaction; confirmed IgE-mediated allergy and concurrent asthma.2
Managing peanut allergy in the community
As with all allergies, the mainstay of peanut allergy management is allergen avoidance, in this case peanuts and anything containing peanuts or peanut products such as unrefined peanut (arachis) oil.
When avoidance fails, which is common, the symptoms of mild allergic reactions can be relieved with antihistamines such as cetirizine and loratadine.8
First-line treatment of anaphylaxis is with adrenaline (epinephrine). Because peanut-allergic patients are at risk of anaphylaxis, they will likely be prescribed auto-injection kits even if previous reactions have been mild. They should carry these at all times for self-administration in the event of an anaphylactic emergency, in which case hospital attention should also be sought immediately.8
Allergic patients and their parents/carers have been found to have poor knowledge of how to avoid peanuts – which might explain why one UK study puts the annual incidence of accidental nut-allergic reactions at 15%. They are also found to have poor knowledge of how to treat an emergency, including use of their adrenaline injector.9,10
Primary care nurses have a key role in reducing this trend through education, advice and signposting, as well as in soothing the anxieties that peanut allergy can cause. Several studies have found peanut allergy to have a ‘profound psychosocial impact’ on patients and carers, with mothers particularly affected.11
Pregnant, breastfeeding and weaning mothers who do not themselves have a peanut allergy may wrongly believe they need to avoid peanuts because of previous guidance from the Food Standards Agency’s Committee on Toxicity; however, this was withdrawn in 2008.12
Management of peanut allergy in school and other community settings is critical so school and community nurses will also need to:
• Set up management plans for peanut-allergic individuals.
• Know how to respond in the case of a severe peanut-allergic reaction or anaphylaxis emergency.
• Teach other school and community staff members how to help keep peanut-allergic individuals safe.13,14
The future of practice in peanut allergy and anaphylaxis
NICE recognises the paucity of guidance on food allergy in adults so we are likely to see further development in this area.7
• The British Society for Allergy and Clinical Immunology has a Nurses in Allergy group and SOPs for use in allergy clinics
• The Anaphylaxis campaign offers online training courses.
• Allergy UK offers advice and resources for patients: https://www.allergyuk.org/peanut-and-tree-nut-allergy/peanut-and-tree-nut-allergy
1. Du Toit et al. Effect of avoidance on peanut allergy after early peanut consumption. N Engl J Med 2016; 374:1435-1443. http://www.nejm.org/doi/full/10.1056/NEJMoa1514209
2. Nice.CG116. Food allergy in under 19s: assessment and diagnosis. February 2011. https://www.nice.org.uk/guidance/cg116
3. Grundy J. Rising prevalence of allergy to peanut in children: data from 2 sequential cohorts. J Allergy Clin Immunol 2002;110:784-9. http://www.jacionline.org/article/S0091-6749(02)01429-X/fulltext
4. Hourihane JO, Aiken R, Briggs R, et al. The impact of government advice to pregnant mothers regarding peanut avoidance on the prevalence of peanut allergy in United Kingdom children at school entry. J Allergy Clin Immunol 2007;119:1197-202. http://www.jacionline.org/article/S0091-6749(07)00245-X/fulltext
5. Bock SA, Muñoz-Furlong A, Sampson HA. Further fatalities due to anaphylactic reactions to foods, 2001-2006. J Allergy Clin Immunol 2007;119:1016-8. http://www.sciencedirect.com/science/article/pii/S0091674906038140
6. Nice. CG134. Anaphylaxis: assessment and referral after emergency treatment. December 2011. https://www.nice.org.uk/guidance/cg134
7. Nice. QS118. Food allergy. March 2016. https://www.nice.org.uk/guidance/qs118
8. Anaphylaxis Campaign. Medication. http://www.anaphylaxis.org.uk/hcp/medication/. Accessed June 7, 2016.
9. Kapoor S, Roberts G, Bynoe Y, et al. Influence of a multidisciplinary paediatric allergy clinic on parental knowledge and rate of subsequent allergic reactions. Allergy 2004;59:185-91. http://onlinelibrary.wiley.com/doi/10.1046/j.1398-9995.2003.00365.x/full
10. Ewan P, Clark A. Long-term prospective observational study of patients with peanut and nut allergy after participation in a management plan. Lancet 2001;357:111-5. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(00)03543-1/fulltext
11. Cummings J, KnibbRC, King RM and LucasJS. The psychosocial impact of food allergy and food hypersensitivity in children, adolescents and their families: a review. Eur J Allergy Clin Immunol 2010;65:933-45. http://onlinelibrary.wiley.com/doi/10.1111/j.1398-9995.2010.02342.x/full
12. COMMITTEE on TOXICITY OF CHEMICALS IN FOOD, CONSUMER PRODUCTS AND THE ENVIRONMENT. STATEMENT ON THE REVIEW OF THE 1998 COT RECOMMENDATIONS ON PEANUT AVOIDANCE. Food Standards Agency. December 2008. http://cot.food.gov.uk/sites/default/files/cot/cotstatement200807peanut.pdf
13. Anaphylaxis Campaign. Training for School Nurses. http://www.anaphylaxis.org.uk/training-for-school-nurses/. Accessed June 7, 2016.
14. Muraro A, Agache I, Clark A, Sheikh A, Roberts G, Akdis CA, Borrego LM, Higgs J, Hourihane JO’B, Jorgensen P, Mazon A, Parmigiani D, Said M, Schnadt S, van Os-Medendorp H, Vlieg-Boerstra BJ, Wickman M. EAACI Food Allergy and Anaphylaxis Guidelines: managing patients with food allergy in the community. Eur J Allergy Clin Immunol 2014. http://healtheducationtrust.org.uk/wp-content/uploads/2015/08/EAACI_Muraro-2014-FA-Community-all12441.pdf