Infant & Paediatric Allergy : Navigating Cow's Milk Protein Allergy in Clinical Practice

What Cow's Milk Protein Allergy Actually Is

Cow's milk protein allergy, or CMPA, is defined as an adverse, immune-mediated reaction to one or more of the proteins found in cow's milk. It is not a single uniform illness but a spectrum of immune responses, all triggered by the same two protein fractions and all capable of producing very different clinical pictures depending on which arm of the immune system is engaged.

The scale of the problem is easy to underestimate. CMPA affects roughly 2.0% to 7.5% of infants globally, which makes it the leading cause of food allergy in children under three years of age. For a condition this common, the diagnostic and management pathway still trips up clinicians and families alike , partly because two very different proteins are doing the damage, and partly because the underlying immunology is frequently misunderstood.

Two proteins, two behaviours

Cow's milk contains two major protein fractions, and they do not behave the same way in the body:

• Casein (76%–86% of milk protein): a highly allergenic, heat-resistant group of proteins (α1, α2, β, and κ-casein). Because casein survives cooking and heat processing, boiling or baking dairy does not reliably remove the allergenic risk.

  Whey (14%–24% of milk protein): dominated by β-lactoglobulin and α-lactalbumin. Whey proteins can sometimes be denatured…