From BMJ: -Link: Overdiagnosis and industry influence: how cow’s milk protein allergy is extending the reach of infant formula manufacturer

This article provides a detailed discussion of this topic. Two key points:

• Because the diagnosis of non-IgE mediated cow’s milk protein allergy is based mainly on a formula trial/reintroduction, it is susceptible to overdiagnosis
• Expert guidelines have been authored mainly by those with conflicts of interest

An excerpt:

Clinicians and patients who spoke to The BMJ are concerned at the wide availability of industry funded online information promoting non-specific symptoms potentially indicating cow’s milk allergy as a diagnosis in exclusively breastfed infants. Although there is evidence that cow’s milk and other food proteins can be transferred from mother to infant in breastmilk, the quantities transferred are likely to be too small to cause symptoms in most infants.