Milk protein allergy

MPA is an adverse immune reaction to one or more of the proteins found in milk, most commonly cow's milk, which are normally harmless to a non-allergic individual.

The pathophysiology of MPA involves an aberrant immune-mediated reaction against milk proteins, with or without involvement of IgE.

The incidence of MPA is estimated at 2-7.5% in the first year of life, with a lower rate in breastfed infants.

Risk factors for developing MPA include a family history of allergies, other atopic diseases, and early introduction of cow's milk.

The clinical course of MPA can vary, but common symptoms include gastrointestinal symptoms, skin reactions, and respiratory problems. In IgE-mediated disease, symptoms such as urticaria, angioedema, vomiting, wheezing, and anaphylaxis occur soon after ingestion of cow's milk, and there is evidence of sensitization (presence of specific IgE). Non-IgE-mediated cow's milk allergy presents with delayed onset of predominantly gastrointestinal symptoms, including proctocolitis, enteropathy, and cow's milk proteins-induced food protein-induced enterocolitis syndrome, or with symptoms resembling functional gastrointestinal disorders, such as infant colic, infant regurgitation, and constipation. In non-IgE-mediated disease, gastrointestinal and cutaneous symptoms improve or resolve with exclusion and reappearing with reintroduction of cow's milk.

The prognosis for MPA is generally good, with most children outgrowing the allergy by adolescence. However, cow's milk allergy is more likely to persist in IgE-mediated disease and where there is greater sensitivity, multiple food allergies, and/or concomitant asthma and allergic rhinitis.