Food Allergy is defined as an immune-mediated hypersensitivity reaction to food and may be divided into:

• Immunoglobulin E (IgE) mediated (immediate-onset/ typically within 2 hours) reactions
• Non IgE-mediated (delayed-onset) reactions- occurs 2 to 48 hours after ingestion
• There are other categories of adverse food reactions which are not allergic, eg food poisoning, viral urticaria, etc.

A health care professional with the appropriate competencies (GP or other health care professional) should take a focused allergy clinical history as per NICE Assessment and allergy-focused clinical history Guidance. NICE Allergy Guidelines (See resources).  

History is paramount in reaching a diagnosis of food allergy taking into consideration of risk factors for allergic aetiology such as family or personal history of atopy.

Based on the clinical history, physically examine the child or young person, in particular for:

• Growth and physical signs of malnutrition
• Signs indicating allergy related co-morbidities (atopic eczema, asthma and allergic rhinitis).

Food allergy may present in a variety of ways ranging from immediate allergic reactions to more chronic presentations such as eczema or gastrointestinal (GI) symptoms. NICE Assessment and allergy-focused clinical history Guidance (see resources). 

The diagnostic process, which may include:

• An elimination diet followed by a possible planned re-challenge or initial food reintroduction procedure.
• Skin prick tests and specific IgE antibody testing and their safety and limitations
• Referral to secondary or specialist care (Hospital Paediatrics & Paediatric Dieticians)

IgE-mediated allergy is suspected:
In NHS Highland, skin prick testing is only available in secondary care, but GPs could request blood tests for specific IgE antibodies to the suspected foods and likely co-allergens.
Base the choice of test on:

• The clinical history and the suitability for, safety for, and acceptability to the child (or their parent and carer).
  And:
• The available competencies of the health care professional.

Tests should only be undertaken by healthcare professionals with appropriate competencies, so primary care clinicians may need to seek help/advice on the appropriateness of allergy testing and or their interpretation from secondary care Paediatricians.

Interpret the results of tests in the context of clinical history.

Do not use atopy patch testing or oral food challenges to diagnose IgE-mediated food allergy in primary care or community settings.

Non IgE-mediated allergy is suspected:

• Try eliminating the suspected allergen for 3 to 4 weeks, then “always” reintroduce.
• Always Consult or refer to a Dietician.
• Skin prick tests and specific IgE-antibodies are not predictive of non-IgE mediated allergy and should not be routinely used.

Based on the allergy-focused clinical history, consider referral to secondary care (Hospital Paediatrics at Raigmore) in any of the following circumstances.

The child or young person has:

• Faltering growth in combination with one or more of the gastrointestinal symptoms described in NICE CG116:  signs and symptoms of possible food allergy. (see resources).  
• Not responded to a single-allergen elimination diet.
• Had one or more acute systemic reactions.
• Had one or more severe delayed reactions.
• Confirmed IgE-mediated food allergy and concurrent diagnosed asthma.
• Significant atopic eczema where multiple or cross-reactive food allergies are suspected by the parent or carer. (Refer to Dermatology as well).

There is:

• Persisting parental suspicion of food allergy (especially in children or young people with difficult or perplexing symptoms) despite a lack of supporting history.
• Strong clinical suspicion of IgE-mediated food allergy, but allergy test results are negative.
• Clinical suspicion of multiple food allergies.

• Complete avoidance of the specific precipitant should be ensured.
• A written individual protocol available from BSACI (Allergy Action Plan)(see resources) must be provided. It is helpful for parents and lay school staff, and is legally required for school staff to be indemnified for administering medication.
• Oral antihistamine should be prescribed for mild reactions. Cetirizine (Non-sedating antihistamine) is generally recommended but Chlorphenamine can be used. Liquid antihistamine preparations are preferred for all age groups because of ease of swallowing and more rapid onset of action.
• In certain circumstances (see below), in addition to antihistamine for oral use, a preloaded device for the delivery of intramuscular adrenalin (epinephrine) (EpiPen) should be available at home, and at school or nursery.
• It is recommended that children should be prescribed 4 auto-injectors (2 for home and 2 for school) - this is due to the possibility of the device misfiring or failure to respond to the first dose – a second dose can be given 5 minutes after the first if required
• Any impact on other health care issues such as vaccination.

Avoidance:

• Children and young people should be referred to a dietician – especially if major food group is implicated (dairy, soya, wheat, eggs, peanut/nuts, fish, shellfish, legumes) multiple food allergies and/or faltering growth.

There is a risk of a severe (life threatening) anaphylactic reaction where the following features are present, and in that case, adrenaline auto injector prescription is recommended if:

• History of previous anaphylaxis (food or exercise induced).
• Previous food reaction involving respiratory or cardiovascular symptoms.
• History of generalized allergic reaction to foods and co-existent asthma requiring regular preventer therapy.

Adrenaline auto injector prescription may be considered if:

• Generalised reaction to trace amounts of food (eg airborne food allergen or contact only via skin).
• Reaction to peanut or tree nut without anaphylaxis.
• Remoteness of home from medical facilities.
• Food allergic reaction in a teenager.

For mild reactions use Cetirizine or Chlorphenamine in solution form.

Epinephrine (Adrenaline):
This is used in the treatment of severe reactions. A variety of delivery systems are available. We recommend the use of EpiPen^® (epinephrine auto-injector) in all instances to facilitate training and prevent confusion (unless there are shortages). It is available in 2 sizes (“EpiPen^® 300 micrograms” and “EpiPen^® Junior 150 micrograms”) and administered as an intramuscular injection into the lateral thigh.

Please check BNF for Children for dosing.

Adrenaline training and differences between different auto-injectors (EpiPen^®, Jext^®, Emerade^®)(see resources)  

• Adrenaline Autoinjector training

Full guidance on auto-injectors (see resources) 

• BSACI guideline: prescribing an adrenaline auto-injector

The hospital:
When the child has been admitted to Hospital at diagnosis:

• Establish what level of treatment may be required in future.
• Where appropriate, provide an adrenaline auto-injector (EpiPen) and an antihistamine to parents on a discharge prescription.
• Demonstrate the use of the adrenaline auto-injector (only if inpatient at time of diagnosis, in other scenarios training is provided via Primary Care e.g. community Pharmacists, Health Visitors, GP Practice Nurses). Demonstration Videos
• Prepare, discuss, and issue an individualised protocol for management of allergic reactions Allergy Action Plan (see resources) (with copies for the notes, the GP, and school nurse/Health Visitors)
• Request GP to update Allergy Action Plan (see resources) annually with parents.
• Ask School Nurse to arrange for protocol to be implemented at school (see below).
• Organise Outpatient Follow up as needed with the named hospital Paediatrician.

In addition, where a food has been identified as the precipitant:

• Provide written advice on food avoidance – and discuss.
• Refer to Dietician.

The CHP:
Make provision in the health visiting/school nursing service in every locality for training of parents and carers, and school or preschool staff in the avoidance of common food allergens, and the administration of antihistamine and intramuscular adrenaline. There should be a system to record the training, accreditation, and re-accreditation of the trainers.

The GP:

• Where appropriate prescribe antihistamine with or without adrenaline for parents to pass on to school/out of school care. (if this has not already been done in hospital).
• Arrange training of parents and carers (and arrange for an appropriately trained School Nurse or Health Visitor to deliver training to school/nursery staff) in basic food avoidance, and the administration of oral antihistamine and intramuscular adrenaline. A demonstration of the use of the adrenaline auto-injector is required as part of the training.
• Provide written advice on food avoidance, see resources Anaphylaxis Org.uk and Allergy UK.   
• Refer to dietician as needed.
• Information on anaphylaxis is available on the Anaphylaxis Campaign see resources: Analphlaxis org.uk, Allergy UK, EpiPen site.   .
• Prepare and discuss individualised protocol for management of allergic reactions. A written individual protocol is required to provide clear guidance to lay school staff, and also to fulfil the legal requirements for school staff to be indemnified for administering medication.
• Allergy action plans for Children from BSACI See resources. A copy should be provided to the parents and the school/Nursery. Do not routinely send to Community Paediatrics unless the child is under their follow up.
• Refer to hospital out-patient clinic as per the suggested referral criteria, above.
• Follow up clinical review frequency will depend on the type of food allergy and be individualised according to family and symptoms and likely to need more frequent review at first diagnosis but once established management plan, a 12 monthly review with adrenaline auto-injector update with annual protocol update (copy to be provided for school), will be adequate.

The Parent:

• Ensure that the adrenaline auto-injector (eg EpiPen) and oral antihistamine are kept in a safe but accessible place.
• Obtain supplies of the adrenaline auto-injectors and oral antihistamine for school/ out of school care. Ensure they are labelled with the child’s name and date of birth – and ensure that they remain in date.
• When the adrenaline auto-injector and oral antihistamine are within 2 months of their “use by” date, contact GP for further supplies.
• Age appropriate discussion with the child, including food avoidance, and when to ask for help.

The school:
See the CHP above and Allergy Action Plans for Children from BSACI (see resources).