Quality statement 2: Diagnosing IgE‑mediated food allergy

Quality statement

Children and young people whose allergy‑focused clinical history suggests an IgE‑mediated food allergy are offered skin prick or blood tests for IgE antibodies to the suspected food allergens and likely co‑allergens.

Rationale

If an allergy‑focused clinical history suggests an IgE‑mediated food allergy, skin prick or blood tests are needed to confirm the diagnosis. A positive test on its own simply shows sensitisation to a food allergen. The diagnosis of clinical allergy depends on the selection and performance of the appropriate test and the interpretation of the results in the context of the clinical history by a healthcare professional with training and skills in this area.

Quality measures

Structure

Evidence of local arrangements and written clinical protocols to ensure that children and young people whose allergy‑focused clinical history suggests an IgE‑mediated food allergy are offered skin prick or blood tests for IgE antibodies to the suspected food allergens and likely co‑allergens.

Data source: Local data collection.

Process

Proportion of children and young people whose allergy‑focused clinical history suggests an IgE‑mediated food allergy who have skin prick or blood tests for IgE antibodies to the suspected food allergens and likely co‑allergens.

Numerator – the number in the denominator who have skin prick or blood tests for IgE antibodies to the suspected food allergens and likely co‑allergens.

Denominator – the number of children and young people whose allergy‑focused clinical history suggests an IgE‑mediated food allergy.

Data source: Local data collection.

Outcome

a) Incidence of IgE‑mediated food allergy.

Data source: Local data collection.

b) Children and young people with IgE‑mediated food allergy who feel, or whose families feel, able to manage their condition.

Data source: Local data collection.

What the quality statement means for service providers, healthcare professionals and commissioners

Service providers (such as primary, community and secondary care providers) ensure that staff can direct, perform and interpret skin prick and blood tests for IgE antibodies to food allergens and co‑allergens in children and young people with suspected IgE‑mediated food allergy. These may be done in primary or community care if staff in the service have the expertise to perform and interpret the tests; otherwise there should be agreed local pathways for referral to secondary care. Services performing skin prick tests should have facilities to deal with anaphylactic reactions.

Healthcare professionals with training and skills in selecting, performing and interpreting skin prick and blood tests (such as GPs, nurses or dietitians) offer children and young people skin prick or blood tests for IgE antibodies to food allergens and co‑allergens if an allergy‑focused clinical history suggests an IgE‑mediated food allergy. Healthcare professionals should only perform skin prick tests if there are facilities to deal with anaphylactic reactions.

Commissioners (clinical commissioning groups and NHS England) commission services that offer children and young people skin prick or blood tests for IgE antibodies to food allergens and co‑allergens if an allergy‑focused clinical history suggests an IgE‑mediated food allergy. Commissioners ensure (for example, through their contracts with providers) that healthcare professionals have undertaken training in selecting, performing and interpreting skin prick and blood tests for IgE antibodies.

What the quality statement means for patients, service users and carers

Children and young people who are thought to have a food allergy caused by IgE antibodies are offered either skin prick or blood tests to confirm the diagnosis.

Source guidance

Food allergy in under 19s: assessment and diagnosis (2011) NICE guideline CG116, recommendations 1.1.5 and 1.1.9

Definitions of terms used in this quality statement

IgE‑mediated food allergy

Allergic reactions caused by IgE antibodies are often immediate and have a rapid onset. Signs and symptoms of IgE‑mediated food allergy are given in recommendation 1.1.1 of the NICE guideline on food allergy in under 19s.

Skin prick test and blood tests for specific IgE antibodies

Skin prick tests should only be undertaken where there are facilities to deal with an anaphylactic reaction.

[Adapted from NICE's guideline on food allergy in under 19s, recommendation 1.1.7]

The choice between a skin prick test and a specific IgE antibody blood test should be based on:

  • the results of the allergy‑focused clinical history and

  • whether the test is suitable for, safe for and acceptable 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.

[Adapted from NICE's guideline on food allergy in under 19s, recommendation 1.1.8]

Guidance on performing and interpreting tests can be found in the British Society of Allergy and Clinical Immunology's cow's milk allergy guideline and egg allergy guideline.

[Expert opinion]