Researchers have found that approximately 1% of children have an allergy to cow’s milk, but up to 14% of families believe their children may have the condition, pointing to official guidelines for detecting cow’s milk allergy as a possible cause for the overdiagnosis, according to a new analysis from the Imperial College London.

Nine official guidelines were analyzed for cow’s milk allergy published between 2012 and 2019, finding that many of the guidelines named symptoms such as excessive crying, regurgitating milk, and loose stools as indications of a cow’s milk allergy. However, the study authors argue that these symptoms are common in normal, healthy babies.

The researchers found that a recent European birth cohort study following more than 12,000 infants in 9 countries showed less than 1% of infants had cow’s milk allergy. Further, they found that in some studies, up to 14% of families believe their infant has a cow’s milk allergy.

This analysis suggests the prescription of specialist formulas for babies with cow’s milk allergy had increased significantly between 2000 and 2018 in countries such as Australia and England without any evidence for an increase in cow’s milk allergy, according to the study authors.

In addition, the research team found that 7 of the 9 guidelines advised breast-feeding women to cut out all dairy from their diet if their child has a suspected cow’s milk allergy. Still, their analysis of 13 studies of breastmilk composition suggests that less than 1 millionth of the protein from cow’s milk travels to breast milk, being too small to trigger a reaction in most allergic children.

“Many infants who are labelled as having milk allergy don’t have the condition. Having a child with suspected milk allergy can be a stressful time for any family,” said Robert Boyle, MD, lead author of the study, in a press release. “Misdiagnosing milk allergy could lead to another condition with similar symptoms being missed, or breast-feeding mothers needlessly following restricted diets – or even stopping breast-feeding altogether. It can also lead to families and the NHS unnecessarily paying for expensive specialist formula.”

Milk allergy is categorized into 2 categories: IgE mediated and non-IgE mediated. IgE mediated allergies have reactions that involve a component in the immune system, with symptoms including vomiting, hives, and difficulty breathing in more severe reactions.

Non-IgE mediated reactions have symptoms that include vomiting, diarrhea, and excessive crying. However, the researchers said that the nature of these symptoms means they are often confused with normal symptoms in young babies.

After analyzing betalactoglobuline, a type of cow’s milk protein known to trigger allergic reactions, the researchers found that the amount of this protein in breast milk was micrograms per liter. This amount was too low to trigger a reaction through breastfeeding for more than 99% of children with cow’s milk allergy, according to the study authors.

Three guidelines were directly supported by formula manufacturers or marketing consultants, and 81% of all guideline authors reported a conflict of interest with formula manufacturers, according to the study.

 “Formula manufacturers may gain from promoting increased cow’s milk allergy diagnosis – by influencing practitioners and parents to use a specialized formula in place of a cheaper formula, and by potentially undermining women’s confidence in breastfeeding, so that specialized formula is used in place of breastmilk, ” Boyle said in a press release. “We must not only critically appraise our current guidelines, and dissociate the development of guidelines from those who may profit from them, but also ensure we are giving each family the best possible care by avoiding overdiagnosis of cow’s milk allergy.”

Milk allergy guidelines may cause overdiagnosis in babies and children. Imperial College London. Published April 13, 2020. Accessed April 16, 2020.