Diagnosis and management

This section contains a background to Cow's Milk Allergy (CMA). It provides information on managing CMA by appropriate assessment and diagnosis according to relevant guidelines, and advice on when to use an amino acid-based formula for infants and children with CMA.

CMA Overview

CMA is a distressing condition for infants and their parents/carers:

CMA is an immune mediated reaction to the proteins within cow's milk and is one of the most common food allergies affecting 2-5% of infants.¹ Up to 40 000 babies a year in the UK may develop CMA.²
Most cases of CMA present in infancy and the majority of children will grow out of the allergy by the age of 5 years.
CMA can be complex to diagnose as many infants will often present with two or more symptoms frequently seen in infancy.
The most common symptoms are of dermatological, gastrointestinal and respiratory origin.

Symptom complexity can delay diagnosis

Data from the UK shows:⁶

It takes an average of 3.6 months from initial GP visit to formal diagnosis

Delayed diagnosis prolongs the distress for infants and their parents and has the potential to impact on infants' growth and development.

CMA imposes a substantial burden on the NHS

Patients with CMA had a mean of 18.2 clinician visits and cost the NHS an estimated £25.6 million during the first 12 months after initial presentation:⁶

The initial aim of management is prompt and accurate diagnosis, removal of cow's milk protein from the diet whilst ensuring the nutritional requirements of the infant/child are met using suitable specialist formulas and dietary modification.

References

Fiocchi A, Brozek J, Schünemann H, et al. WAO J 2010;3:57-161
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
Meyer R, Schwarz, C & Shah, N. Current Allergy & Clinical Immunology 2012;25(1):10-17.
Høst A. Ann Allergy Asthma Immunol 2002;89 (6 suppl 1):33-37.
Koletzko S, Niggemann B, Arato A, et al. J Pediatr Gastroenterol Nutr 2012; 55(2):221-229.
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.

CMA assessment

NICE have produced a guideline (CG 116) to aid in the diagnosis and assessment of food allergy in children and young adults. The first steps are initial recognition, an assessment of the symptoms and the allergy focused history. The guideline includes a series of algorithms, which have been reproduced with the permission of NICE for use on this website.

1. Initial recognition

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.

2. History and examination

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)

3. Consider referral to secondary or specialist care

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.

Diagnosis

CMA can be classified according to whether the allergic reaction is an IgE mediated (within 2 hours) or a non IgE mediated (delayed, chronic) response. The NICE guideline helps determine the type of allergy and outlines the tests that should be used to confirm the diagnosis.

Once an allergy is suspected NICE recommends that an elimination diet should be tried for 2 to 6 weeks. The allergen should then be reintroduced to confirm diagnosis. NICE also recommends that the advice of a dietitian with appropriate competencies should be sought to assist with nutritional adequacies, timings of elimination and reintroduction, and follow-up.

The algorithms found below have been reproduced with the permission of NICE.

Once the diagnosis of the CMA has been confirmed, including the type of allergy (IgE or non IgE), a management plan can be established.

1. Testing for food allergy

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.

2. Testing for IgE-mediated food allergy: skin prick test for specific IgE antibodies

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.

3. Testing for non-IgE-mediated food allergy: elimination test

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.

4. Consider referral to secondary or specialist care

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

Management

CMA is managed by excluding cow's milk protein from the diet.

Breast feeding is always the preferred way to feed an infant. If an infant is being breast fed, the mother needs to follow an exclusion diet with the support of the dietitian to ensure that the maternal diet is adequate. Calcium and Vitamin D supplements are recommended.

Formula fed infants will need to be provided with a replacement hypoallergenic formula, either an extensively hydrolysed or amino acid formula.

There are specific times where the use of an amino acid formula is indicated.