Prevalence and risk factors for milk allergy overdiagnosis in the BEEP trial cohort.

BACKGROUND: Cow's milk allergy (CMA) overdiagnosis in young children appears to be increasing and has not been well characterised. We used a clinical trial population to characterise CMA overdiagnosis and identify individual-level and primary care practice-level risk factors. METHODS: We analysed data from 1394 children born in England in 2014-2016 (BEEP trial, ISRCTN21528841). Participants underwent formal CMA diagnosis at ≤2 years. CMA overdiagnosis was defined in three separate ways: parent-reported milk reaction; primary care record of milk hypersensitivity symptoms; and primary care record of low-allergy formula prescription. RESULTS: CMA was formally diagnosed in 19 (1.4%) participants. CMA overdiagnosis was common: 16.1% had parent-reported cow's milk hypersensitivity, 11.3% primary care recorded milk hypersensitivity and 8.7% had low-allergy formula prescription. Symptoms attributed to cow's milk hypersensitivity in participants without CMA were commonly gastrointestinal and reported from a median age of 49 days. Low-allergy formula prescriptions in participants without CMA lasted a median of 10 months (interquartile range 1, 16); the estimated volume consumed was a median of 272 litres (26, 448). Risk factors for CMA overdiagnosis were high practice-based low-allergy formula prescribing in the previous year and maternal report of antibiotic prescription during pregnancy. Exclusive formula feeding from birth was associated with increased low-allergy formula prescription. There was no evidence that practice prescribing of paediatric adrenaline auto-injectors or anti-reflux medications, or maternal features such as anxiety, age, parity and socioeconomic status were associated with CMA overdiagnosis. CONCLUSION: CMA overdiagnosis is common in early infancy. Risk factors include high primary care practice-based low-allergy formula prescribing and maternal report of antibiotic prescription during pregnancy.

Trends in use of specialized formula for managing cow's milk allergy in young children.

BACKGROUND: Excessive use of specialized formula for cow's milk allergy was reported in England, but complete analysis has not been undertaken and trends in other countries are unknown. Some specialized formula products, especially amino-acid formula (AAF), have high free sugars content. We evaluated specialized formula trends in countries with public databases documenting national prescription rates. METHODS: Cross-sectional analysis of national prescription databases in the United Kingdom, Norway and Australia. Outcomes were volume and cost of specialized formula, and proportion of infants prescribed specialized formula. Expected volumes assumed 1% cow's milk allergy incidence and similar formula feeding rates between infants with and without milk allergy. RESULTS: Prescribed volumes of specialized formula for infants rose 2.8-fold in England from 2007 to 2018, with similar trends in other regions of the United Kingdom. Volumes rose 2.2-fold in Norway from 2009 to 2020 and 3.2-fold in Australia from 2001 to 2012. In 2020, total volumes were 9.7- to 12.6-fold greater than expected in England, 8.3- to 15.6-fold greater than expected in Norway and 3.3- to 4.5-fold greater than expected in Australia, where prescribing restrictions were introduced in 2012. In Norway, the proportion of infants prescribed specialized formula increased from 2.2% in 2009 to 6.9% in 2020, or 11.2- to 13.3-fold greater than expected. In 2020, specialized formula for infants cost US$117 (103 euro) per birth in England, US$93 (82 euro) in Norway and US$27 (23 euro) in Australia. Soya formula prescriptions exceeded expected volumes 5.5- to 6.4-fold in England in 1994 and subsequently declined, co-incident with public health concerns regarding soya formula safety. In 2020, 30%-50% of prescribed specialized formula across the three countries was AAF. CONCLUSIONS: In England, Norway and Australia, specialized formula prescriptions increased in the early 21st century and exceeded expected levels. Unnecessary specialized formula use may make a significant contribution to free sugars consumption in young children.

Detection and management of milk allergy: Delphi consensus study.

BACKGROUND: There is significant overdiagnosis of milk allergy in young children in some countries, leading to unnecessary use of specialized formula. This guidance, developed by experts without commercial ties to the formula industry, aims to reduce milk allergy overdiagnosis and support carers of children with suspected milk allergy. METHODS: Delphi study involving two rounds of anonymous consensus building and an open meeting between January and July 2021. Seventeen experts in general practice, nutrition, midwifery, health visiting, lactation support and relevant areas of paediatrics participated, located in Europe, North America, Middle East, Africa, Australia and Asia. Five authors of previous milk allergy guidelines and seven parents provided feedback. FINDINGS: Participants agreed on 38 essential recommendations through consensus. Recommendations highlighted the importance of reproducibility and specificity for diagnosing milk allergy in children with acute or delayed symptoms temporally related to milk protein ingestion; and distinguished between children directly consuming milk protein and exclusively breastfed infants. Consensus was reached that maternal dietary restriction is not usually necessary to manage milk allergy, and that for exclusively breastfed infants with chronic symptoms, milk allergy diagnosis should only be considered in specific, rare circumstances. Consensus was reached that milk allergy diagnosis does not need to be considered for stool changes, aversive feeding or occasional spots of blood in stool, if there is no temporal relationship with milk protein ingestion. When compared with previous guidelines, these consensus recommendations resulted in more restrictive criteria for detecting milk allergy and a more limited role for maternal dietary exclusions and specialized formula. INTERPRETATION: These new milk allergy recommendations from non-conflicted, multidisciplinary experts advise narrower criteria, more prominent support for breastfeeding and less use of specialized formula, compared with current guidelines.