Diagnosis and management

1. Fiocchi A, Brozek J, Schünemann H, et al. WAO J 2010;3:57-161
2. 2011/12 UK Birth Rate, Office of National Statistics, ONS http://www.ons.gov.uk/ons/taxonomy/index.html?nscl=Population Number of births in UK 2012 = 812,970 
3. Meyer R, Schwarz, C & Shah, N. Current Allergy & Clinical Immunology 2012;25(1):10-17.
4. Høst A. Ann Allergy Asthma Immunol 2002;89 (6 suppl 1):33-37.
5. Koletzko S, Niggemann B, Arato A, et al. J Pediatr Gastroenterol Nutr 2012; 55(2):221-229.
6. Sladkevicius E, Nagy E, Lack G et al. Resource implications and budget impact of managing cow milk allergy in the UK. J Med Econ 2010;13(1):119-28.

Consider Food Allergy in a child or young person who:

• has one or more signs and symptoms of possible food allergy (pay particular attention to persistent symptoms that involve different organ systems) or
• has had treatment for atopic eczema, gastro-oesophageal reflux disease or chronic gastrointestinal symptoms (including chronic constipation) but their symptoms have not responded adequately.

Do not offer allergy tests without first taking an allergy-focused clinical history.

A healthcare professional with the appropriate competencies (a GP or other healthcare professional) should take an allergy-focused clinical history tailored to the presenting symptoms and age of the child or young person using the questions below.

The clinical history should include:

• any personal history of atopic disease (asthma, eczema or allergic rhinitis)
• any individual and family history of atopic disease (asthma, eczema or allergic rhinitis) or food allergy in parents or siblings
• details of any foods that are avoided and why
• an assessment of presenting symptoms and other symptoms that may be associated with food allergy, including:
  • age at first onset
  • speed of onset
  • duration, severity and frequency
  • setting of reaction (for example, at school or home)
  • reproducibility of symptoms on repeated exposure
  • what food and how much exposure to it causes a reaction
• cultural and religious factors that affect the child's diet
• who has raised the concern and suspects the food allergy
• what the suspected allergen is
• the child's feeding history, including age of weaning and whether they were breastfed or formula-fed (if the child is currently being breastfed, consider the mother's diet)
• details of previous treatment, including medication, for the presenting symptoms, and the response to this
• any response to the elimination and reintroduction of foods
• physical Examination
• Based on the clinical history, physically examine the child or young person, paying particular attention to:
• growth and physical signs of malnutrition
• signs indicating allergy-related comorbidities (atopic eczema, asthma and allergic rhinitis)

Based on the allergy-focused clinical history, consider referral to secondary or specialist care 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 signs and symptoms of possible food allergy
• 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 asthma
• significant atopic eczema where multiple or cross-reactive food allergies are suspected by the parent or carer

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

National Institute for Health and Care Excellence (2011) Adapted from CG 116 Food allergy in children and young people. Diagnosis and assessment of food allergy in children and young people in primary care and community setting. London: NICE. Available from www.nice.org.uk/CG116 Reproduced with permission.

Alternative diagnostic tools not recommended.

Do not use the following alternative diagnostic tests in the diagnosis of food allergy:

• vega test
• applied kinesiology
• hair analysis

Do not use serum-specific IgG testing to diagnose food allergy.

Offer a skin prick test and/or blood tests for specific IgE antibodies to the suspected foods and likely co-allergens.

Base choice of test on:

• the clinical history and
• the suitability, safety for, and acceptability to the child or young person (or their parent or carer) and
• the available competencies of the healthcare professional to undertake the test and interpret the results

Tests should only be undertaken by healthcare professionals with the appropriate competencies to select, perform and interpret them.

Only undertake skin prick tests where there are facilities to deal with an anaphylactic reaction.

Interpret test results in the context of clinical history.

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

Try eliminating the suspected allergen (normally for between 2-6 weeks), then reintroduce. Seek advice from a dietitian with appropriate competencies about nutritional adequacies, timings of elimination and reintroduction, and follow-up.

Taking into account socioeconomic, cultural and religious issues, offer information on:

• what foods and drinks to avoid
• how to interpret food labels
• alternative sources of nutrition to ensure adequate nutritional intake
• the duration, safety and limitations of an elimination diet
• oral food challenge or reintroduction procedures, if appropriate, and their safety and limitations

If allergy to cow's milk protein is suspected, offer:

• food avoidance advice to breastfeeding mothers
• information on appropriate hypoallergenic formula or milk substitute to mothers of formula-fed babies

Seek advice from a dietitian with appropriate competencies.

Based on the allergy-focused clinical history, consider referral to secondary or specialist care 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 signs and symptoms of possible food allergy
• 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 asthma
• significant atopic eczema where multiple or cross-reactive food allergies are suspected by the parent or carer

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

National Institute for Health and Care Excellence (2011) Adapted from CG 116 Food allergy in children and young people. Diagnosis and assessment of food allergy in children and young people in primary care and community setting. London: NICE. Available from www.nice.org.uk/CG116 Reproduced with permission.

1. Meyer R et al. J Allergy Clin Immunol Pract. 2017.09.003
2. Fox et al. Clin Transl Allergy (2019); 9: 40
3. Luyt et al. Clin Experimental Allergy;44:642-672