Hospital‐Based Food Challenges for the Diagnosis of Food Allergy—A BSACI Clinical Practice Statement

ABSTRACT

Food challenges play an important role in the diagnosis and management of food hypersensitivity. Although the gold‐standard is the double‐blind, placebo‐controlled food challenge, an open challenge, where the challenge food is known to both the patient and the allergy team, is a practical and effective tool for use in daily clinical practice. A food challenge can help determine the presence or absence of a food allergy if the history and allergy tests are discordant, or if resolution of the allergy is expected. The outcome of a food challenge can result in either confident introduction or re‐introduction of foods or provide clarity on which foods or forms of the food need to be avoided. Challenges can be a positive or negative experience for individuals; to maximise the potential for positive impact, food challenges should be overseen by individuals with relevant knowledge, skills and experience, and take place in a suitable clinical area with appropriate access to emergency support and a pathway for admission to an inpatient facility. Challenge foods should be age‐specific, in an appropriate form (uncooked, cooked, baked, composite food), and given in incrementally increasing amounts until an age‐specific top or cumulative dose has been consumed. The decision to pause or stop a challenge should be based on international guidance and clinician judgement, but also consider an individual's symptom history and their preferences.

• Food challenges are a useful diagnostic and management tool for food allergy, and should be overseen by experienced practitioners with access to emergency support.

• Challenge foods should be given in incrementally increasing doses, and the challenge paused or stopped according to clinician judgement and international guidelines.

• Alongside other interventions, food challenges can ensure diagnostic accuracy and facilitate safe food reintroduction.

Abbreviations

AAI

adrenaline autoinjector

BSACI

British Society of Allergy and Clinical Immunology

CPS

Clinical Practice Statement

EAACI

European Academy of Allergy & Clinical Immunology

ED

eliciting dose

FA

food allergy

FC

food challenge

FHS

food hypersensitivity

FPIES

food protein‐induced enterocolitis syndrome

IgE‐FA

IgE‐mediated food allergy

LTP

lipid transfer protein

Non‐IgE‐FA

non‐IgE‐mediated food allergy

PEFR

peak expiratory flow rate

PFS

pollen food syndrome

WDEIA

wheat‐dependent exercise‐induced anaphylaxis

1. Introduction

A food challenge (FC) is the gold standard test to confirm the presence or absence of allergic reactions to a food [1]. A survey of all paediatric allergy services in the United Kingdom (UK) reported that 90% of secondary care providers and 100% of tertiary providers undertook food challenges [2]. Far fewer FC are undertaken in adults; whilst 82% of members of the British Society of Allergy and Clinical Immunology (BSACI) who responded to a survey reported undertaking FC in children, only 16% of survey respondents undertook FC in adults, and 3% in both children and adults [3]. The BSACI survey provided details of the type of food challenges undertaken, where these challenges take place, which personnel are involved, how challenge foods are prepared and administered and what treatment is given in the advent of a reaction. The results demonstrated variation in practice, and therefore this BSACI Clinical Practice Statement (CPS) aims to provide practical advice and a clinical toolkit to support the delivery of safe and successful FC for both children and adults in UK allergy centres. It also incorporates guidance from, and aims to complement, international consensus documents [1, 4].

2. Methodology

The multidisciplinary writing group consisted of individuals who responded to an open call to BSACI members, and those representing all specialist groups within the BSACI, ensuring a multi‐disciplinary perspective. The group agreed the scale and sections of the paper, and a small team of writing group members was allocated to each section. The author of each section undertook a literature search when relevant, although much of the paper is devoted to very practical matters which do not always have published evidence to support them. The whole writing group reviewed the paper, and the final version was circulated to patient organisations and the BSACI membership before ratification and publication.

2.1. The Purpose and Scope of Food Challenges

An accurate clinical history, supported by appropriate testing (specific IgE/skin prick testing) is often sufficient to diagnose IgE‐mediated Food Allergy (IgE‐FA) [1]. A FC can support diagnosis and also confirm either resolution or the persistence of the allergy, but it can serve multiple other purposes. Indications for challenge are listed in Table 1. The purpose of the FC should be clearly understood and agreed by staff and patients together before being undertaken. An open FC, where both the clinician and patient are aware of the food being challenged, is most utilised in clinical practice for IgE‐FA. Other types of challenge for IgE‐FA (Table 2) may be more appropriate in certain situations [4, 5, 6]. For non‐IgE‐FA, a FC is mainly utilised for individuals with food protein‐induced enterocolitis syndrome (FPIES), due to the absence of suitable biomarkers to confirm diagnosis or resolution, and the potential for severe reactions [7]. If a non‐immune‐mediated Food Hypersensitivity (FHS) is suspected, a controlled dietary exclusion followed by reintroduction is the best diagnostic option, with monitoring via a symptom diary [8, 9, 10].

TABLE 1.

Indications for oral food challenge (adapted from [1]).

Diagnostic clarity	Test result is positive but with an inconsistent clinical history or one suggesting tolerance, or there is co‐sensitisation to cross‐reacting allergens (house dust mite, pollen) which may invalidate the result
	Test result is negative but there is a high index of suspicion, reluctance to introduce/reintroduce foods due to anxiety, or severe reactions reported
	Disparity between results from different tests results or between test results and clinical history
	The food has never been eaten
	There is suspected resolution of the allergy due to approaching transfer to adult services or accidental ingestion has not resulted in an allergic reaction.
Individual management advice	Clarification of the reaction threshold, to facilitate individualised avoidance advice
	There is a need to increase food choices, for example, diet is already restricted due to another condition (coeliac disease, diabetes), or vegetarian or vegan diet.
Demonstrate phenotype for therapeutic purpose	Occupational/functional: application to the armed forces or food‐services occupations, going to university, gap year travel, moving into the workplace
	Therapeutic Intent: where further information on thresholds is required, for example, extreme anxiety about low dose exposure or prior to and after commencing immunotherapy

TABLE 2.

Types of FC used when IgE‐FA is suspected or has been disproved.

Type of FC	Definition	Use in clinical settings
Open food challenges (OFC)	Both patient and staff know that the ‘test’ allergen is being eaten	Most OFC will be undertaken in hospital, using an incremental dosing schedule
Single‐blind placebo‐controlled food challenges, SBPCFC	Two challenges on separate days, one active and one placebo. Only the patient is blinded as to which day is ‘active’	Useful in cases where anxiety may be responsible for subjective or non‐specific symptoms
Double‐blind placebo‐controlled food challenge, DBPCFC	As above, but both staff and the patient are blinded as to which day is ‘active’	As above, but enables staff to make a more objective assessment Mainly used in research settings
Supervised feeds (open)	Total dose is delivered in one age‐appropriate portion or split into 2 smaller portions (~25% and 75%) to be consumed over 30–60 min	Used when high clinical suspicion that the patient is tolerant but the patient/parent too anxious to undertake home introduction
Home introductions	The test food is consumed at home in incremental doses	Used there is a minimal/no risk of IgE‐FA to that specific food but supports patient/family to re‐introduce the food

2.2. Contraindications for Challenge

Absolute contraindications include pregnancy, unstable angina, severe/chronic lung disease, asthma exacerbation and suboptimal asthma control. Considerations which make assessment of a clear outcome more challenging include inability to stop antihistamines or biologics prior to FC. In these cases, the nuances of interpreting the outcome of a FC undertaken on antihistamines/biologics should be discussed with the patient/parent, including the probable need to repeat it following their discontinuation if diagnostic clarity is required. Extreme anxiety, neurodiversity, food aversion, textural hypersensitivity or needle phobia are not contraindications but may require individual adjustments to the challenge protocol.

2.3. Preparation Prior to a FC

2.3.1. Environment and Equipment (Table S1)

A FC should take place in a designated area of a clinical facility, with access to a trained resuscitation team, overnight care and a designated pathway to transfer care to a High‐Dependency or Intensive Care setting, especially if offsite. The BSACI survey revealed that FC in the UK either take place in a day care unit (74%) or inpatient facility (26%) [3]. Lower risk FC (e.g., supervised feeds) undertaken in outpatient settings should have pathways to transfer patients to in‐patient settings if treatment escalation is required. Multiple patients can undertake a FC in the same room, providing each has a designated seat/bed a sufficient distance apart, and privacy available should reactions occur. Accommodation should be made to support individual adaptations of space and facilities due to cultural needs, hearing or vision impairment. Staff should be able to easily simultaneously observe and assess each patient, with immediate access to portable monitoring (for multiple patients), treatment and crash trolleys.

2.3.2. Staff

All FC should be supervised and supported by healthcare professionals experienced in undertaking FC and managing allergic reactions. The size and composition of the team and level of support, whether onsite or remote, should be appropriate to the patient cohort and level of FC risk/difficulty. Nurses and dietitians with extended roles support/lead many food challenge services in the UK, providing expertise with regard to patient clinical care, management of food challenge materials and post challenge advice. The team should be proficient in patient/family communication including discussing/consenting for FC, preparing, checking and administering and adjusting doses, assessing patients throughout FC, recognising and treating reactions including anaphylaxis, and documenting FC procedures and progress. They should have regular (consider at least quarterly) training in symptom recognition and anaphylaxis management including simulation, (jointly with supporting hospital teams where possible), alongside standard Trust‐level mandatory requirements for basic/intermediate life support training.

2.3.3. Patient Consent and Assent

It is recommended that written consent is obtained, either prior to or on the day of the FC; evidence suggests this is currently not universal practice [2]. All patients, including children, young people and adults with additional needs, should be actively involved in the decision making and consent process in a developmentally appropriate manner, encouraged/enabled to express their views and preferences and given sufficient time to decide. All discussions and paperwork should be in a language and format that is accessible to the patient (BSL support, F2F interpreter, online interpretation platforms). The discussion should include the purpose and benefit of FC, the recommendation regarding eating the food following a non‐reactive challenge, risks and mitigation strategies, alternative approaches, procedural aspects, feasibility (likelihood of completion due to taste aversion, fussy eating or extreme anxiety), and logistics. The consent document should outline the risks of a FC, including the possibility of anaphylaxis. Age‐specific written information should also be provided, which reflects the local set up and processes. It should include a contact phone number, department email, details of who provides the FC food (department/patient) and whether cultural or religious requirements can be met if the food is provided by the department.

2.3.4. Medications

Antihistamines should be discontinued for a minimum of 3 days, depending on the antihistamine, but inhaled corticosteroids, nasal steroid sprays and topical treatments do not need to be stopped [5]. For other medications, an individual decision should be made regarding possible effects on the underlying condition if the medication is stopped, versus the potential for a more difficult to assess or treat reaction if the medication is not stopped. For example, beta‐blockers may impair the action of adrenaline, but after reviewing the indication, the FC may still go ahead with glucagon available.

2.3.5. Communication

Contacting the patient/parent a short time prior to the challenge ensures that they are fully prepared for the procedure. Information should include location, appointment duration, stopping medication, and what to bring with them (food and drink, entertainment, change of clothes, and FC food if applicable) and address any pre‐appointment anxiety.

2.4. Preparation on the Day of the FC

2.4.1. Assessment (Table S2)

Depending on the patient's age and clinical history, baseline observations may include weight, height, temperature, oxygen saturations, pulse rate, blood pressure, Peak Expiratory Flow Rate (PEFR)/spirometry, examination of the skin, eyes, nose and throat and auscultation of the chest. The following issues should be appraised to confirm fitness for FC:

• Current/recent illness—may increase the risk of a severe reaction and/or affect the interpretation of the FC outcome.

• Medications—check discontinuation of antihistamines, changes in prescription or new medical diagnosis since last review.

• Asthma stability—PEFR should be > 80% predicted/expected at baseline; if not, then further asthma assessment may be indicated.

Urticaria/angioedema/eczema—current/ongoing exacerbations should be assessed for appropriateness to proceed, documented and monitored prior to and during the FC if it goes ahead. A photo taken immediately prior to commencing the FC can support accurate detection of skin changes (e.g., lip swelling, subtle facial oedema) during the challenge.

• Sensitive peri‐oral skin—consider applying a barrier cream around the mouth prior to starting the FC

2.4.2. Rescue Medications (Table 3)

TABLE 3.

Rescue medications required for a FC.

	Route
Medication immediately available
Adrenaline	IM +/−autoinjector +/− nasal
Antihistamine (not chlorphenamine)	Oral
Salbutamol	Inhaled and spacer, or Nebulised
Corticosteroids	Oral
Crystalloids	IV
Medication which may be required in refractory anaphylaxis
Adrenaline	Infusion/nebulised
Crystalloids	IV
Corticosteroids	IV
Magnesium sulphate	Nebulised or IV
Ipratropium Bromide	Nebulised/inhaled
Glucagon—if patient taking beta blockers	IV
Oxygen	Inhaled

Abbreviations: IM, Intramuscular; IV, Intravenous.

Age‐appropriate medications to treat any reactions should be immediately available and checked prior to starting the FC [4]. The availability of medications should cover all outcomes including refractory anaphylaxis.

2.4.3. Food and Drink

A light meal is advised ≥ 2 h prior to the start of the challenge; this is the most common practice in the UK [3]. The European Academy of Allergy & Clinical Immunology (EAACI) guideline on food allergy diagnosis proposes commencing a FC 2–4 h after a light meal [1]. During the FC, 46% of BSACI survey respondents allow snacks whereas 42% only allowed water [3]. If it is essential to allow a snack during the challenge (e.g., toddlers or individuals with diabetes), this should be a known tolerated food, not cross‐reactive to the challenge food, or high in fat as this might delay the absorption of the challenge food [11].

2.5. Food Challenge Procedures (Tables 4 and 5 and Tables S3–S5)

TABLE 4.

PRACTALL doses for commonly challenged foods [1].

Challenge food	Protein/100 g	Co‐FID code*	Food weight (in g) providing the equivalent allergen protein amount (mg) for each PRACTALL dose
			10 mg	30 mg	100 mg	300 mg	1000 mg	3000 mg	Cumulative
Cow's Milk whole full fat	3.4	12–596	0.3	0.9	2.9	8.8	29.4	88.2	130.5 a
Cow's milk yoghurt (Greek style)	5.7	12–555	0.2	0.5	1.7	5.3	17.5	52.6	77.8 a
Cheddar Cheese	25.4	12–346	0.04	0.1	0.4	1.2	3.9	11.8	17.4 a
Whole hens egg	12.6	12–937	0.08	0.2	0.8	2.4	7.9	23.8	35.2 a
Cod	23.9	16–373	0.04	0.1	0.4	1.3	4.2	12.5	18.5 a
Salmon (baked)	25.2	16–359	0.04	0.1	0.4	1.2	4	11.9	17.6 a
Tuna (tinned)	25.4	16–417	0.04	0.1	0.4	1.2	3.9	11.8	17.4 a
Tuna (baked)	32.3	16–400	0.03	0.1	0.3	0.9	3.1	9.3	13.7 a
Prawns (shrimp)	23.8	16–245	0.04	0.1	0.4	1.3	4.2	12.6	18.6 a
Squid (raw)	15.4	16–263	0.06	0.2	0.7	1.9	6.5	19.5	28.9 a
Mussels (cooked)	17.7	16–390	0.06	0.2	0.6	1.7	5.6	17	25.2 a
Peanut (roasted)	24.7	14–834	0.04	0.1	0.4	1.2	4	12.1	17.8 a
Peanut butter	22.8	14–892	0.04	0.1	0.4	1.3	4.4	13.2	19.4 a
Almond (blanched)	21.2	14–896	0.05	0.1	0.5	1.4	4.7	14.2	20.9 a
Brazil nut	14.3	14–871	0.07	0.2	0.7	2.1	7	20.9	31
Cashew nut (roasted)	20.5	14–812	0.05	0.1	0.5	1.5	4.9	14.6	21.6
Macadamia nut	7.9	14–891	0.13	0.4	1.3	3.8	12.7	38	56.3
Hazelnut (blanched)	14.1	14–874	0.07	0.2	0.7	2.1	7.1	21.3	31.4
Pecan nut	9.2	14–837	0.1	0.3	1.1	3.3	10.9	33	48.7
Pistachio nut (roasted)	17.9	14–840	0.05	0.2	0.6	1.7	5.6	16.7	24.9
Walnut	14.7	14–879	0.07	0.2	0.7	2	6.8	20.4	30.2
Pine nut	14	14–839	0.07	0.2	0.7	2.1	7.1	21.4	31.6
Coconut (desiccated)	5.6	14–873	0.18	0.5	1.8	5.3	17.8	53.6	79.2
Soy milk unsweetened	2.4	12–524	0.4	1.2	4.2	12.5	41.7	125	185
Tahini	18.5	14–847	0.05	0.2	0.5	1.6	5.4	16.2	23.9
Sesame seeds	18.2	14–844	0.05	0.2	0.5	1.6	5.5	16.5	24.3
Poppy Seeds	20.6	13–849	0.05	0.1	0.5	1.5	4.9	14.6	21.5
Pumpkin seeds	24.4	14–842	0.04	0.1	0.4	1.2	4.1	12.3	18.2
Sunflower seeds	19.8	14–845	0.05	0.1	0.5	1.5	5.1	15.2	22.4
Mustard powder	28.9	17–362	0.03	0.1	0.3	1	3.5	10.4	15.3
Chickpeas (canned)	8.4	13–670	0.12	0.4	1.2	3.6	11.9	35.7	52.9 a
Lentils (green/brown)	7.8	13–661	0.13	0.4	1.3	3.8	12.8	38.5	56.9 a
Bread (wholemeal)	9.4	11–981	0.11	0.3	1.1	3.2	10.6	31.9	47.1 a
Pasta, white, cooked	5.5	11–1129	0.18	0.5	1.8	5.4	18.2	54.5	80.6 a

^a Insufficient cumulative dose for adults—see Supporting Information.

^* McCance and Widdowson Composition of Foods Integrated Dataset (CoFID) (Gov.UK, 2021).

TABLE 5.

Example of un‐weighed dosing protocol for children (see full table in the Supporting Information).

Food (see appendix for recipes)	Dosing schedule	Age range ~ school age (> 5 years old)
		Cumulative portion size
Peanut butter	1/32nd tsp, 1/16th tsp, 1/8th tsp, 1/4th tsp, ½ tsp, 1 tsp	~2 tsp
Tree nut paste	1/32nd tsp, 1/16th tsp, 1/8th tsp, 1/4th tsp, ½ tsp, 1 tsp	~2 tsp
Finely ground up nuts in biscuit (e.g., peanut or tree nuts)	Small crumb, 1/16th biscuit, 1/8th biscuit, 1/4th biscuit, ½ biscuit, (remaining ~1/16th biscuit)	Total weight = 8 g nut weight of each type of nut
Tahini (sesame seeds)	1/32nd tsp, 1/16th tsp, 1/8th tsp, 1/4th tsp, ½ tsp, 1 tsp	~2 tsp
Wheat	Small crumb, 1/16th biscuit, 1/8th biscuit, 1/4th biscuit, ½ biscuit, (1 & remaining ~1/16th biscuit)	2 biscuits, for example, shortcake or 1 shortcake biscuit or 1 rich tea figure
Oat	Small crumb, 1/16th biscuit, 1/8th biscuit, 1/4th biscuit, ½ biscuit, (1 & remaining ~1/16th biscuit)	2 biscuits, for example, shortcake, GF oat biscuit
Fish	Portion of cooked fish equivalent to 2 fish fingers: 1/16th fish finger, 1/8th fish finger, ¼ fish finger, ½ fish finger, 1 fish finger	2 fish fingers = 60 g of cooked, chilled fish.
Cooked lentil (e.g., tinned)	5 lentils, 10 lentils, 1 tsp, 2 tsp, 5 tsp, ½ tablespoon	Small portion 1 tablespoon
Uncooked fruit or vegetable	½ slice, 1 slice, 2 slices, 4 slices, then ½ fruit 1 slice = ~2 cm round, for example, banana, carrot	1 small fruit/portion of fruit
Baked milk biscuit (low‐level baked milk protein)	Small crumb, 1/16th, 1/8th, 1/4th, ½, ¾ biscuit. Home‐made recipe: use 1 mL milk per biscuit	~1.5 malted milk biscuit
Baked milk muffin (higher‐level baked milk protein)	Small crumb, 1/16th, 1/8th, ¼, 1/3, ½ muffin	1 muffin (20 mL milk in 1 muffin)
Baked egg [1 medium egg = 8 cakes] (partial baked egg protein)	Small crumb, large crumb, 1/16th, 1/8th, ¼, ½ cake, remaining cake	Total dose = 1 fairy cake

Note: NB: Adapted from protocols used by Leicester NHS Trust paediatric allergy team.

2.5.1. Lip Rub

Applying the challenge food to the lips or skin prior to oral consumption is commonly undertaken in UK secondary care allergy services [2, 3], but is not recommended practice as local reactions are often false positives [1, 4, 12].

2.5.2. Dosing Regimens

An incremental, age‐appropriate, individually tailored dosing regimen is recommended, commencing with a dose containing a level of protein unlikely to provoke symptoms [13]. The most widely adopted approach is the PRACTALL expert consensus, which recommends a starting dose of 3 mg protein, with subsequent doses containing 10, 30, 100, 300, 1000 and 3000 mg protein (Table 4) [4]. Alternatively, an un‐weighed, incremental dosing schedule can be used, with doses given over 3–6 steps and providing a maximum dose equivalent to an age‐appropriate serving size [5]. This method is most suitable for fruits/vegetables but can also be used for other foods, providing the first dose is sufficiently small for high protein foods, and the final dose is age appropriate. Table 5 is an example of one UK centre's approach to non‐weighed FC dose schedules. The BSACI survey reported that 43% always used the PRACTALL regime, and 38% either PRACTALL or an incremental dosing regime.

The clinical history should dictate the starting dose; a reported severe reaction, or one to trace amounts justifies a lower starting dose, for example, 1 mg/3 mg protein. Conversely, negative allergy tests and/or a high suspicion of tolerance supports a higher starting dose of 30 mg/100 mg. Alternatively, the top two PRACTALL doses can be given 30 min apart, or the full cumulative dose given over 30 min (supervised feed). Whatever dosing regimen is used, the final/cumulative dose should be equivalent to an age‐appropriate serving of food [1, 4, 5, 14, 15], and if not reached, an additional dose may be required, especially in adults (Tables 4 and 5, and Tables S3 and S4) [13]. The cumulative or top dose of a less common food should be determined according to the protein/100 g, which can then help define the smaller doses. The amount of protein predicted to elicit objective allergic signs in a percentage of a population of allergic individuals (population eliciting dose ED_P) can vary between foods, and where known, should inform the starting and top dose (Table S5) [1, 13, 14, 15, 16]. FC in infants may require special adaptation, especially during ongoing weaning. Specific low dose FC for infants have been developed to enable dietary advancement with repeated or escalating doses challenged at 3–6 monthly intervals [17].

The time between doses should not be less than 15–20 min and should take account of individual history. Most UK services report a dose interval of 20–30 min and guidelines recommend 15–30 min (EAACI) or 20–30 min (PRACTALL), but suggest a 30–60 min interval may improve clarity and reduce the risk of severe reactions where required [1, 3, 4]. A longer dose interval (≥ 30 min) may be required for those with significant anxiety, previous severe/delayed reactions or when a baked matrix (baked milk/egg) may delay symptom presentation [18]. A shorter dose interval may be suitable for patients with rapid‐onset symptoms, for example, in pollen food syndrome (PFS). Irrespective of interval, there should be stringent observation of patients, and dose intervals increased following evidence of reaction development.

For FPIES a challenge dose of 0.15–0.3 g of food protein per kg/body weight is recommended, administered as a single dose or three equal doses over a 30‐min period, followed by a minimum 4‐h final observation period [19]. Rescue medication (ondansetron, IV fluids) should be available. If severe reactions are reported, 25% of the standard serving should be given, followed by a full serving 2 h later if asymptomatic [20]. If significant IgE‐sensitisation has developed subsequent to the FPIES diagnosis a modified FC that incorporates initial lower doses (similar to IgE‐FA FCs) and also extends the observations period is suggested [7]. The schedule may differ if the index food versus a related food is being assessed.

2.5.3. Food Safety (Tables S6 and S7)

Services that provide or prepare food for FC should have a designated food preparation area, which meets organisational hygiene recommendations and minimises cross‐contamination. All preparation should be according to Standard Operating Procedures (SOP) and food hygiene practices compliant with national standards and regularly audited. All staff involved in FC should be aware of food safety standards and the correct storage of challenge foods. Perishable foods should be stored in a refrigerator and/or freezer prior to the challenge, and between doses, the temperature of which should be regularly monitored. If the PRACTALL method is used, scales are required which can weigh down to 0.0001 g and are serviced and calibrated regularly. Each FC dosing container should be labelled with patient identification details, challenge food and dose, and checked prior to administration.

2.5.4. Food Choices for Challenge

Patient/family preferences for the challenge food, including form, vehicle and methods of masking flavour and taste should be agreed ahead of the FC. Foods may carry different utility and importance to individuals from diverse cultural, socioeconomic or health backgrounds. A food perceived to be easily avoided might be an important part of a traditional cuisine, or a plant‐based diet. An individual/family without oven facilities may not be able to bake a muffin for a milk/egg challenge. The food might need to be fresh (raw), cooked or processed, with the most allergenic form of the food being challenged, unless less allergenic forms of the food (e.g., baked egg/milk) are still being avoided [21, 22]. If taste preference could affect consumption, then the challenge food can be hidden in another tolerated food, for example, yoghurt or mashed potato. Discussions with the patient and family should determine the best format of the food from the perspective of cultural relevance, culinary traditions and family priorities, which may impact on the preparation of the food challenge, and who will supply it. If the challenge food is in an unusual form, for example, herb, spice or composite food, it may be necessary to challenge with the food in the format that provoked the reaction. Different food brands may contain varying concentrations of protein (e.g., tahini can contain 16–26 g protein/100 g), affecting the starting and cumulative doses.

2.6. Challenge Foods (Table 6)

TABLE 6.

Matrix/Vehicles for the delivery of the allergen.

Cow's milk	Baked—malted milk biscuit, Biscotti, muffin Cooked/fermented—custard, white sauce, pizza, yoghurt/fromage frais Raw/uncooked/pasteurised—fresh milk
Hen's egg	Baked—muffin, cupcake, scone (see Appendix for recipes) Cooked—hard‐boiled egg, quiche, omelette, tortilla, pancake. Ensure Lion's stamp Raw—mousse, ice cream
Soy	Bread, soy flour in home‐made food, tofu, tempeh, soy‐based yoghurt, soy milk
Peanut or tree nut	Peanut or tree nut butter, thinned/diluted for babies, added to yoghurt or on its own. Biscuit containing ground nut/nut flour, nut muffin (baking may affect allergenicity), nut snack, for example, Bamba, breakfast cereal or a favourite food, whole nuts (only in children aged 5 years or older). For whole nuts use roasted (peanut, cashew, pistachio), blanched (almond, hazelnut) or raw (Brazil nut, walnut pecan nut, macadamia nut)
Fish	Cod, salmon, tuna‐cooked and eaten plain or canned (salmon/tuna) or made into a potato fishcake or sandwich filling. If sushi/raw fish involved, challenge to trigger food.
Shellfish	Cooked shrimp, fresh water north Atlantic and king prawns, canned crab, canned mussels, pre‐cooked squid or scallops (available from large supermarkets). Can also be finely chopped and mixed into sandwich filling or with potato in fishcake.
Fruit/veg	Age‐appropriate portion fruit eaten raw. Can be finely chopped and added to porridge or a dessert, for example, yoghurt, or sandwiched between cake/bread or biscuits (e.g., for banana). Vegetables can be added to mashed potato
Cereals	Wheat—use products with a high percentage of wheat protein in the ingredients, for example, plain biscuit (Rich Tea, shortbread), wheat breakfast cereal, for example, Weetabix (contains barley malt extract), shredded wheat, pasta, semolina. Puffed wheat for low dose challenge Barley—boiled pearl barley, home‐made vegetable soup containing barley Corn—pre‐made polenta, corn cracker, cornflakes (malt‐free), home‐made cornflake cakes, plain popcorn, home‐made cornflour biscuit Rice—boiled rice, rice cake, breakfast cereal, baby rice, rice flour biscuit, rice milk Oats—GF oat cakes, flapjack, porridge oats, oat cereal, oat milk (check ingredients) Rye—crispbread, rye bread, home‐baked item made with rye flour
Seeds	Sesame—tahini paste Sunflower and pumpkin seeds—whole seeds, seeded bread or cracker (check package), paste, home‐made biscuits with ground seeds Mustard—mild American mustard on bread, honey mustard dressing, dish containing mustard or added to scone/biscuit—mustard type needs to be discussed.
Legumes	Canned or cooked green garden peas, cooked yellow split pea, pea protein flour (green or yellow pea, follow label for preparation instructions). Lentils, chickpeas, or beans, either eaten plain or added to a home‐cooked dish. If beans are canned in tomato sauce they must be washed before consumption. Lupin—lupin flour added to a cooked food, or in a home‐made biscuit
Coconut	Fresh coconut, coconut cream/canned milk
Other foods	Other food can be sandwiched between bread (if tolerated) or blended into shakes or homemade biscuits if necessary. Always ensure all other ingredients contained within a composite food (foods which contain multiple ingredients) or used in the food vehicle for the food challenge have been tolerated many times before

2.6.1. Cow's Milk and Hen's Egg

BSACI guidance recommends that children with low‐risk allergy to cow's milk or hen's egg should start home introduction using a cow's milk/egg ladder [23, 24] which starts with baked/extensively heated forms of cow's milk/hen's egg. This approach is not currently recommended for other groups (e.g., older children or those with other risk factors for a severe reaction). A hospital challenge may be indicated where there is a history of previous anaphylaxis, high parental anxiety or a reported reaction to baked cow's milk/egg. If the challenge is non‐reactive (negative), then other forms of cow's milk and hen's egg can be considered for challenge [25, 26]. Most studies on the predictive value of allergy tests to cow's milk and eggs have been undertaken in children, so their use in determining likely resolution in adults is unknown. Lack of sensitisation to the major allergens Bos d 8 (milk) and Gal d 1 (egg) may predict tolerance [27, 28], but it is recommended that children with persisting allergy to cow's milk/egg and adults who are still completely or partially avoiding egg or milk should have a hospital FC. Adolescents and adults with new‐onset symptoms to cow's milk/egg or who are sensitised and avoiding these foods but have not experienced any reactions, will benefit from a hospital challenge due to the high likelihood more severe reactions [29, 30].

2.6.2. Fish and Shellfish

Allergy to fish is more prevalent in childhood and may resolve. It is usual to challenge with cooked/canned fish as, although the major fish allergen β‐parvalbumin is heat stable, other fish allergens are susceptible to heat or water‐soluble so may not be present in cooked or canned fish, for example, tuna and salmon [31, 32]. The choice of fish used in the challenge should relate back to the clinical history and be relevant to the cultural norms of the patient. As fish has a distinctive taste and smell it may be necessary to improve palatability for children, for example, by presenting the fish in the form of a fish cake. Fish oil supplements may provoke symptoms in a fish allergic individual, so a challenge may be needed if they are required for nutritional reasons.

Shellfish reactions most commonly occur in adults and usually involve crustaceans, especially prawn/shrimp [31]. There are species differences in allergens, so the FC should include the species that caused the reaction (if known) and one alternative species [33, 34]. In the UK, king, tiger and North Atlantic prawns are the most often available types of prawns. Allergy to molluscs is much less prevalent; therefore, a home challenge can be recommended if tests are negative. For both fish and shellfish, PPT with the species used for challenge is helpful, especially when there are no SPT extracts or specific IgE tests available for less common species.

2.6.3. Peanut and Tree Nut

The form of nut challenged (roasted, baked, raw) should be relevant to the patient history and given in an age‐appropriate form and amount (Table 6). Nut butters should contain 100% nut and preferentially be free from sugar and salt. Recipes can be used to ‘hide’ nuts but should not be high in fat as this may reduce the bioavailability of the nut allergen [11]. Challenge vehicles high in fat can delay digestion, which may result in higher doses being given before a challenge is halted (which may increase the potential for a more severe reaction). Adults and children aged ≥ 1 year with a high likelihood of tolerance can have a mixed nut supervised feed. For children, this is usually in the form of a biscuit. In adults, it is usual to challenge with whole nuts, except in situations of extreme anxiety. For patients with PFS, the tolerance of a food containing finely crushed roasted nuts, but symptoms to fresh nuts can illustrate the safety of roasted nuts, foods containing low quantities of nuts or those with trace nut warnings.

2.6.4. Soya and Other Legumes

If all soya is being avoided then challenging with soya flour (in non‐seeded bread) may be a useful assessment. If soya flour is tolerated, then soya milk is the best form for challenge, although this may be more likely to provoke PFS in susceptible individuals. In adults, if a fermented soy product has provoked symptoms, then soy sauce and tempeh should also be challenged, as fermented soy can provoke symptoms in isolation [35, 36, 37]. A FC for other legumes can start with canned or cooked legumes, but may also need to involve processed vegan products and legume flours, as these contain much higher concentrations of legume protein than more natural sources [38, 39].

2.6.5. Seeds

A sesame challenge often utilises sesame paste (tahini) as it contains all the sesame allergens including those present in the oil‐bearing part of the seed. It can be disguised and allows for a low starting dose, which is important especially in adults who may have inconclusive or falsely negative tests [40, 41, 42]. A seeded challenge (where the outer cellulose hull limits exposure to the allergen during digestion, especially if the seeds are not chewed and thus broken to release sesame protein) may be helpful for some individuals (e.g., in a household having lots of sesame‐foods, and an individual who is anxious about accidental sesame seed exposures). Given the differences in allergenicity, the purpose, interpretation and dietary implications of these challenges must be explained and fully understood by the patient. Reactions to other seeds are increasingly being reported, but there is little data on the efficacy of tests, and challenge may be the best diagnostic option [43, 44, 45, 46, 47, 48].

2.6.6. Fruits and Vegetables

Challenges to fruits and vegetables can either be to determine a diagnosis of a primary allergy to an individual fruit or vegetable, for example, kiwifruit, or assist in the diagnosis and/or management of PFS or LTP allergy. Individuals with PFS or LTP allergy often exclude multiple fruits and vegetables, so FC can also help improve nutritional intake and quality of life and facilitate home introduction of other foods. Fruit FC should use ripe, uncooked, fresh fruit, as cooking, drying, or canning destroys the allergens involved in PFS, although frozen fruit may still provoke reactions [49]. However, individuals with LTP allergy may react to both raw and cooked fruits/vegetables [50]. The amount of allergen in fruits can also vary due to varietal differences [51]. It is often best to cut the fruit up and avoid seeds and skin initially as these are more likely to provoke symptoms. Vegetables should be challenged either cooked or raw depending on the form normally eaten. People with LTP allergy might tolerate raw tomato but not concentrated forms such as tomato puree, so both need to be challenged [52]. Individuals sensitised to LTP allergens may have a non‐reactive FC if the history suggests reactions may be linked to a co‐factor, for example, exercise, alcohol or pain relief [50].

2.6.7. Wheat

FCs should ideally involve different forms of wheat, such as durum wheat found in pasta, and bread wheat found in most other wheat products. There are differences in the proteins of these two main forms of wheat and some patients may tolerate pasta but react to a breakfast cereal or bread [53, 54]. A wheat challenge should therefore involve both types of wheat, so depending on the patient history, the first challenge should be with bread or a plain wheat breakfast cereal followed by cooked pasta. Wheat products should be free of rye and barley unless there is known tolerance to these cereals. An extended post‐FC observation time (beyond 2 h) is useful as reactions may be delayed. In adults, reactions to wheat are often co‐factor‐dependent, but if a challenge with the co‐factor is not possible, then a larger final or cumulative dose of wheat should be given, for example, 2–3 slices of bread or large bowl of pasta [55, 56, 57].

2.6.8. Herbs and Spices

Spice allergy most often involves chilli, paprika, fenugreek and mustard [13]. Fresh herbs such as parsley, dill, coriander and fennel can provoke allergic reactions due to cross‐reactivity with mugwort pollen [49]. The suspected herb or spice should be challenged in the format that provoked the reaction, for example, fresh/dried or part of a composite meal.

2.6.9. Food Additives

There is little published data on FC to food additives except for the preservative sodium metabisulphite [58]. A suggested incremental dosing schedule comprises 5, 20 and 50 mg of sodium metabisulphite, mixed into sulphite‐free juice or cordial and given 40 min apart, with/without placebo doses. The 5 mg dose may only be necessary for highly sensitive individuals [59]. Sulphites can provoke moderate or severe reactions including wheeze; therefore, it is preferable that challenges are avoided in individuals with asthma [59, 60].

2.7. Challenge Management

2.7.1. In Challenge Assessment

Regular observations during the challenge are not routinely indicated. Reassessment of observations should, however, be undertaken if clinical symptoms or changes in behaviour or appearance of physical signs are noted.

2.7.2. Stopping Criteria (Table 7)

TABLE 7.

Symptoms which may be sufficient to delay or stop a food challenge (adapted from [2]).

	Continue with the challenge	Delay/stop the challenge	Stop the challenge
Accompanying notes	Use clinical judgement in individual cases and objective measurements if considered necessary	1 symptom—consider delaying the next challenge dose if reaction is increasing. Occasionally, clinical judgement may direct stopping at this stage. ≥ 2 symptoms from distinct organ categories—stop the challenge	1 symptom—stop the challenge
Skin	Few areas of faint erythema perioral urticaria or due to contact Any scratching	Erythema < 50% body surface 1–2 urticarial lesions (not perioral or due to contact) Prominent lip or ear oedema	Erythema > 50% body surface ≥ 3 urticarial lesions (not perioral or due to contact) Facial +/− uvula oedema or generalised oedema
Eyes & Nose	Minimal redness or eye rubbing Mild infrequent rhinitis	Conjunctival hyperaemia (without prior rubbing) Persistent and significant rhinorrhoea or sneezing or rhinitis
Respiratory	Intermittent cough and throat clearing Isolated chest tightness with no other objective signs	Frequent cough but no respiratory compromise, for example, wheeze, tachypnoea, significant peak flow drop	Cough with respiratory compromise a Any wheeze a Chest tightness with a fall in PEFR ≥ 20% a
Oro‐pharyngeal	Itchy mouth or itchy throat or intermittent throat clearing	Persistent throat tightness or pain > 20 min	Non‐transient hoarseness/stridor a
Gastro‐intestinal	Nausea (any severity/frequency) Mild abdominal pain Vomit due to gag or taste aversion	Persistent (> 20 min) non‐distractable abdominal pain with a decrease in activity levels in children 1 episode of diarrhoea	1+ vomit episode due to allergic reaction 2+ diarrhoea episodes
Cardio‐vascular	Mild tachycardia		Clinically significant hypotension a Cardiovascular shock/collapse a

Note: Red shades indicates stop, yellow is pause/wait and green is go/continue with the challenge.

^a Manage as anaphylaxis.

Each centre should have agreed stopping criteria based on published guidance; Table 7 summarises the consensus PRACTALL stopping criteria [4]. The survey of UK paediatric allergy services reported only 60% of services use a standardised protocol for recording symptoms and signs during a challenge [2]. Adherence to stopping criteria ensures inconclusive symptoms are not erroneously designated as a positive reactive challenge, and avoids exposure to a higher dose than is necessary for diagnostic purposes. Mild abdominal pain, oral itch, transient localised lip oedema, peri‐oral urticaria, facial flushing or slightly red eyes should be noted, and may prompt assessment, but alone are insufficient to stop the FC. However, in supporting the diagnosis of pollen food syndrome, persistent or recurrent oropharyngeal pruritus or abdominal pain may provide sufficient evidence to stop the FC. Moderate nausea or chest tightness may warrant further evaluation prior to continuing. Small children often become upset and clingy, and children and adults may experience mood changes prior to a definite reaction. In such cases, or where the reaction is unclear, extending the observation period by delaying the next dose may allow further sign(s) to appear and reassures the patient prior to continuing the FC. An objective sign (e.g., vomit, rhinitis, wheeze, dyspnoea, angioedema urticaria, hypotension) increases the certainty that a true clinical reaction has occurred [61].

2.7.3. Medical Management of Reactions

There must be a formal pathway for managing the escalation of symptoms, including alerting the supervising clinician, administering emergency medication, cannulation, and pausing other FCs if awaiting resus team support. If stopping criteria are reached, reactions should be treated as per guidelines. With anaphylaxis, an appropriate dose of nasal or IM adrenaline should be promptly administered before any additional medications are given (e.g., adjunctive treatments, like salbutamol or nebulised adrenaline depending on the symptoms present). If an adrenaline autoinjector (AAI) is used then patients of an appropriate age, or parents of younger children should be encouraged to (self) administer the AAI where possible. This experience can be empowering and facilitates checking and positively reinforcing good technique. In the rare event that this is not effective in managing anaphylaxis, there are national recommendations for the management of refractory anaphylaxis which teams should be familiar with.

2.7.4. Challenge Outcome

The FC processes, interventions and outcome, should be explained step‐by‐step, using encouraging and supportive language to describe the implications and consequent actions. It is important to describe the challenge outcome as reactive or non‐reactive, and avoid terms such as ‘failed’ or ‘passed’. The focus should be on the symptoms experienced and how these were assessed and treated. Reflecting on the outcome can enhance a patient's understanding about their allergy. FCs have the potential to improve quality of life for patients and caregivers irrespective of challenge result [62, 63], and ensuring a positive experience for patients/families is important.

2.7.5. Observation Period

A one‐hour observation period after the last dose is often sufficient if minimal or no symptoms are reported, or if the patient has a diagnosis of PFS. In other scenarios or if co‐factor‐induced allergy is suspected, a two‐hour observation period after the last intervention is recommended. It is proposed that the patient consumes a snack or light meal during the observation period, followed by monitoring to check for symptoms secondary to further allergen absorption. Discharge timings after anaphylaxis vary from 2 to 12 h, with the observation duration based on the Resuscitation Council UK guidelines [64].

2.8. Follow‐Up and Aftercare (Table 8)

TABLE 8.

Suggested dietary advice following non‐reactive paediatric FCs.

Pre‐FC allergy status	Possible dietary options following non‐reactive FC
Previous definite reaction (i.e., certain clinical allergy)	Encourage portion‐sized dosing with a frequency that family can practically manage (more frequent exposure, for example, 3–4 times a week may be encouraged in infants/toddlers where tolerance may still be being established)
2Avoiding due to significant levels of sensitisation (IgE)	Encourage portion‐sized dosing with a frequency that family can practically manage
3Avoiding due to low levels of sensitisation (IgE)	Encourage inclusion in the diet in practical amounts and frequencies for the family (specifics may not be necessary)
4Avoiding without sensitisation	Allow family to introduce as directed by the child according to their taste preferences and nutritional requirements

Whatever the outcome, all patients/parents should receive team contact details, a treatment plan and training on reaction management for either a delayed reaction post‐FC (occurs in 3%–13% of FC) or following home reintroduction [65].

2.8.1. Non‐Reactive (Negative) Challenge

Follow‐up will maximise the likelihood of successful introduction (if appropriate) and minimise ongoing allergen avoidance due to anxiety [66, 67, 68]. The approach to reintroduction will depend on why the food was being excluded. Children and adults who are sensitised and/or previously had symptoms to the food are advised to consume a normal portion of the food regularly, although the optimal frequency and quantities are currently unknown (Table 8) [65]. If multiple foods have been de‐labelled (e.g., all tree nuts), practical individualised advice will aid successful dietary inclusion. Those with low/no sensitisation or no previous reactions to the food do not need to consume the food regularly. Those allergic to a single food, who successfully reintroduce that food at home, do not need to renew their adrenaline prescription on expiry. Following successful introduction, updated allergy action plans can also be provided by community‐based HCPs.

2.8.2. Reactive (Positive) Challenge

Post‐challenge information should include level of allergen avoidance, treatment options, advice on emergency medications, new/updated allergy action plan and the next appropriate timepoint for reassessment especially if anaphylaxis has occurred. Those who reacted on the first or second dose should continue rigorous avoidance of the known allergen and carry rescue medication including adrenaline where indicated. Those who reacted at a high dose (3000 mg, large cumulative dose, normal portion) should be given individualised advice on whether foods containing small or trace amounts of allergen can be included in the diet. They should continue to carry rescue medication, but shared decision‐making should determine whether adrenaline is required. If resources are limited, signposting to patient‐focussed allergy organisations can be helpful, especially for those who are anxious. Thought should also be given as to whether patients need to be aware that co‐factors such as fatigue, exercise and illness may lower the threshold dose for a reaction in some individuals [69].

2.8.3. Communication With Primary Care and Other Stakeholders

This should include the challenge food, cumulative quantity consumed (food amount and estimated protein amount), outcome (reactive/non‐reactive/inconclusive), dietary recommendations, changes to emergency medication, updates to allergy coding, who to contact should queries arise or reactions occur, and when re‐referral for re‐assessment is warranted. Updates should also be made to any written health plans for carers and schools.

2.9. Governance Considerations and Minimum Data Set (Tables S8 and S9)

The FC service should be reviewed at least annually. Governance processes should review:

• Patient information and consent

• Standard Operating Procedures: food storage and preparation, dosing schedules and administration, management of reactions

• Training of staff, emergency preparedness and escalation processes

• Verbal and written communication with stakeholders pre and post the FC

• Overall longitudinal service review including changing FC trends

The ability to audit FC services depends on the quality of documentation; templates improve consistency, reinforce training and ensure decision‐making is clear. A database of FC activity can make service evaluation more accurate and efficient, and enables detection of patterns of safety and activity. Incidents that should prompt an early audit/review include a patient experiencing refractory anaphylaxis, a national alert, or a proposed change in foods used for FCs. Audit results can be utilised for training staff and tracking patient activity. Service evaluation should include:

• Assessing whether all current food allergies are accurately documented in the patient record

• Proportion of non‐reactive, reactive, anaphylaxis, cancelled FCs

• Frequency of dose 1 and top dose reactions

• Trends in FC being ordered

• Effect of patient feedback on FC procedures and practice

3. Conclusion

The diagnosis and management of FA is complex. Dietary restriction not only affects nutritional status and dietary choice, it also adversely affects interactions at school or the workplace, travel and holidays and quality of life. Although allergy tests are useful, currently the most effective test remains the FC. Providing robust confirmation of the presence or absence of an IgE‐FA by undertaking a FC ensures the correct diagnosis and provides the patient with insight into their condition and the confidence to either manage their food allergy or reintroduce foods back into their diet. To facilitate nationwide access to safe, patient‐centred FC services, the BSACI has established a portal of FC resources to complement this publication.

Author Contributions

Isabel Skypala organised the BSACI Food Challenge survey, wrote the abstract, introduction, purpose of food challenge, dosing regimens, co‐wrote sections on foods for challenge. Heidi Ball provided extensive input into the sections on Pre‐FC preparation, presentation of foods and dosing regimens, Kavitha Sooriyakumar wrote the original sections on contraindications to food challenge, medical management of reactions, preparation prior to a FC (staffing). Daisy Stevens wrote the section on equipment and made comments on the final draft. Veeresh Patil wrote the section on preparation for challenge. Claudia Gore contributed to the section on foods for challenge. Ahmed Elghoudi wrote the section on audit. Karen Wright contributed to the section on foods for challenge and also had input into some of the tables. Samantha Blamires and Justine Dempsey reviewed and edited some of the tables in the main document and Supporting Information. Kosta Stoenchev contributed to the section on the settings for food challenge. Rebecca Knibb, Jill Edmonds, Matt Doyle and Natasha Gunawardana reviewed the document and sent comments. Leonard Siew contributed a food challenge dosing schedule. Nandinee Patel co‐wrote several sections and tables and together with Isabel Skypala, put all of the sections together, rationalised the text and tables, edited all the sections, drafted the paper and edited the final draft.

Funding

The writing group received no funding for the production of these recommendations. However, from 2022 to 2026, BSACI has received funding from the following pharmaceutical industry sponsors: Abbott, Aimmune, ALK Abello, Allergy Therapeutics, ARS Pharma, AstraZeneca, Bausch & Laum, Bio‐Diagnostics Ltd., BioCryst Pharmaceuticals, Captium, DBV Technologies, Dermal Laboratories, Diagenics, Dr. Faulk Pharma, Dyson, Ga2lan, Glenmark, InBio, KalVista, L'Oreal, Mead Johnson Nutrition, Mylan, Naturpharma, NeilMed Pharmaceuticals, Novartis, Nutricia, Pharming, Reckitt Benckiser, Sanofi Genzyme, Scope Eyecare, Fusion Allergy, Shire, Stallergenes Greer, Takeda, Thermo Fisher Diagnostics Ltd., UK Masto, Viatris.

Conflicts of Interest

Isabel J. Skypala has received honoraria from ThermoFisher, HVD, the Royal College of General Practitioners (RCGP) and TouchIME. Nandinee Patel is supported through the NIHR Biomedical Research Centre based at Imperial College Healthcare NHS Trust and Imperial College London. Natasha Gunawardana has received advisory fees from ALK. Karen Wright is supported through the NIHR Biomedical Research Centre based at the University of Southampton. Other authors have no relevant COI to declare.

Supporting information

Table S1: Environment and equipment for a food challenge.

Table S2: Pre‐FC checklist.

Table S3: Example of un‐weighed dosing protocol providing an age‐appropriate portion for children (adapted from protocols used by Leicester NHS Trust paediatric allergy team).

Table S4: Food Challenge total cumulative dose for those aged 16 years and over.

Table S5: Eliciting Doses for different foods in different percentages of the allergic population*.

Table S6: Correct Storage of foods for challenge—check also local hygiene guidelines.

Table S7: Food preparation. The requirement for the items listed below will depend on whether the unit will provide foods for food challenge or require patients to bring the foods they will be challenged to, to the appointment. Different centres select different service designs based on resources (suitable on‐site hospital kitchen) and local patient needs (diversity of foods being challenged to and financial capacity of local patient population). This area should be separated from any staff kitchen areas. All foods should be prepared according to best practice and food hygiene regulations.

Table S8: Minimum data recorded/audit template spreadsheet for documentation.

Table S9: Data collection for audit.

Data Availability Statement

The authors have nothing to report.