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Food Allergy


Introduction

Type 1 hypersensitivity reactions (IgE mediated food allergy) occur withinseconds to minutes after ingestion of a trigger food and can include urticaria, angioedema, itching, cough, hoarseness, wheeze, breathlessness, nausea, vomiting or abdominal pain2.

*This list is not exhaustive.

Non-IgE mediated food allergy or food intolerance often results in gastrointestinal symptoms only and the timing is often not suggestive of a type 1 hypersensitivity.

 

In scope            IgE mediated food allergy in adults

Not in scope      If there are associated systemic features refer to Anaphylaxis

     Non IgE mediated (food intolerance)

     Atopic eczema – eczema alone is not caused by food allergy in adults, and this should not be a focus of investigation

     Allergy suspected to be caused by anything other than food

 

Red flags

If there are associated systemic features please refer to anaphylaxis guideline and follow national guidance on treatment.

 

Management Optimisation

In the absence of red flags and emergency management, follow the steps below:

1. Clinical history and prompt documentation of reactions is paramount.

Include:

  • Foods and medications consumed within 4 hours prior to reaction
  • Activities/exercise/exposures over that period
  • Tolerance of these foods/drugs since the episode (this excludes these as a cause of the reaction)
  • Any dietary implications (e.g. nut allergy in a vegetarian)
  • Any other foods that are avoided and the reason for avoidance

2. Advise patients to avoid potential triggers identified in the history pending further investigations
 

3. Advise caution when eating away from home or with food not prepared by the patient
 

4. Self-injectable adrenaline guidance:

  • All patients prescribed self-injectable adrenaline must have appropriate training in their use. Please consider the following:
    • Adrenaline should be co-prescribed with caution for patients with cardiovascular disease on betablockers and/or ACE inhibitors
    • Asthma care should be optimised4
    • Any patient with a tendency to angioedema should avoid ACE-I
  • All patients should be provided with an emergency plan2 due to the difficulty in ensuring complete avoidance of potential trigger.

Action Plan with Adrenaline

Action plan WITHOUT adrenaline.pdf

 

5.The use of alternative methods of diagnosis (e.g. food-specific IgG testing, vega testing, kinesiology, hair analysis, pulse testing2, naturopathy) or treatment (e.g. homeopathy, acupuncture, reflexology, chiropractic therapy, or osteopathy) is not recommended5.

 

Investigations prior to referral

No investigations in primary care are required prior to referral.

If specific IgE is requested prior to referral it should only be done for foods known to be involved in the reaction. Please note:

  • negative specific IgE is not sufficient to rule out a food allergy. Patients must continue to avoid any foods implicated in reactions.
  • tolerance of the implicated food since the reaction excludes allergy.

Patch testing, skin prick testing and oral food challenges should not be undertaken in primary care2.

 

Advice and Guidance

No advice and guidance service is available.

 

Referral Criteria

Adults (16 years or over):

  • With suspected food allergy (where one or multiple foods are implicated)
  • With suspected food reactions where food trigger is not clear
  • Where food avoidance would cause important dietary restriction (e.g. nuts in a vegetarian or coeliac disease patient)
  • Where the food allergy has occupational implications (e.g. military employment)

 

Referral Instructions

There is a referral form available, which would help to minimise returned referrals. Only the relevant section needs to be completed. GPs have the right to refer via referral letter in the usual way.

 

Supporting Information

For patients

For professionals

 

References

  1. Overview | Food allergy | Quality standards | NICE
  2. Food allergy | Health topics A to Z | CKS | NICE
  3. Adrenaline & Anaphylaxis | Anaphylaxis UK
  4. BSACI guideline: prescribing an adrenaline auto-injector. Pamela Ewan, Nicola Brathwaite, Susan Leech, David Luyt, Richard Powell, Stephen Till, Shuaib Nasser, Andrew Clark. First published: 29 September 2016 https://onlinelibrary.wiley.com/doi/10.1111/cea.12788
  5. https://www.bsaci.org/resources/allergy-management/food-allergy/investigations/other-tests/

 

Page Review Information

Review Date                      22 January 2025

Next Review Date              22 January 2027

Speciality Lead GP            Dr Kate Northridge

Contributors                       Dr Catherine Elliott, Specialist Doctor in Allergy, University Hospital Plymouth