Health guidelines may lead to overdiagnosis of child milk allergy, experts warn

Babies and young children could be wrongly diagnosed with a milk allergy due to medical guidelines linked to the condition, scientists have suggested.

An investigation by Imperial College London and Moscow’s Sechenov University has found that around 1% of children have a cow’s milk allergy, but up to 14% of families believe their child has the condition.

The researchers analysed nine official guidelines for cow’s milk allergy published between 2012 and 2019, in a review published in the journal JAMA Pediatrics.

They pointed to official guidelines for detecting cow’s milk allergy as a possible cause for the overdiagnosis, noting that some of the advice was backed by formula manufacturers or marketing consultants.

The prescription of specialist formulas for babies with cow’s milk allergy 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 analysis.

The guidelines came from a range of medical organisations in a number of countries, many of which were in Europe.

Dr Robert Boyle, consultant allergy specialist and lead author of the research from Imperial’s National Heart and Lung Institute, said: “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.

“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.”

The researchers pointed out that excessive crying, regurgitating milk and loose stools were named as possible symptoms in the guidelines – but such issues are also common in healthy babies.

They also looked into the possible links between the formula manufacturers and the authors of the guidelines. They found that eight out of 10 of all guideline authors reported a conflict of interest.

The team also found seven of the nine guidelines advised breast-feeding women to cut out all dairy from their diet if their child was suspected of having a cow’s milk allergy.

The researchers suggested this could be unnecessary.

It was noted that less than one millionth of the protein from cow’s milk travels through to breast milk and this would be too small to trigger a reaction in most allergic children.

The team analysed data on the amount of a type of cow’s milk protein known to trigger allergic reactions, called betalactoglobulin. They found that the amount of this protein in breast milk was just micrograms – or millionths of a gram – per litre.

Milk allergy is most common in children under two years old. Symptoms can include vomiting, hives and a severe reaction in rare cases that can lead to the breathing difficulty called anaphylaxis.

Vomiting, diarrhoea or excessive crying are other potential signs.

Dr Boyle said: “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.”