The guideline, the first of its kind, is designed to assist GPs in the clear diagnosis and assessment of the condition in children.

Hospital admissions in the UK for food allergies have increased five-fold since 1990.

In addition, a fifth of children who report an allergy also wrongly self-report diagnoses and avoid eating certain foods as a result, but do not have a confirmed diagnosis.

The guideline advises GPs to take an allergy-focused clinical history if allergy is suspected, including a physical examination. Diagnosis may include skin prick and/or blood tests for immunoglobulin antibodies, which can suggest particular allergic reactions.

But diagnostic tests available on the high street or the internet are not recommended as there is little evidence the tests work.

Referral to secondary care should be considered if the child has ongoing problems including faltering growth, vomiting, abdominal pain, loose or frequent stools, or constipation, in combination with other GI symptoms.