Milk allergy

A milk allergy is a food allergy, an adverse immune reaction to one or more of the constituents of milk from any animal (most commonly alpha S1-casein, a protein in cow's milk). This milk-induced allergic reaction can involve anaphylaxis, a potentially life-threatening condition.

Allergy

A person with milk allergy can be reactive to one of dozens of the proteins within milk. The most common one is alpha S1-casein.

Alpha S1-caseins do differ between species; but almost all commercially farmed animals produce antigenically similar milk. This explains why someone with an allergic reaction to cow's milk cannot drink sheep's or goat's milk, but can drink breast milk without an allergic reaction.

The allergy may be caused by the presence of specific milk antibodies or specific milk-sensitive lymphocytes. This gives rise to the two distinct forms of milk allergy: Antibody-mediated allergy, and Non-antibody mediated allergy.

Antibody-mediated allergy

The effects of antibody-mediated allergy are rapid in onset, evolving within minutes or seconds. These allergies always arise within an hour of drinking milk; but can occasionally be delayed longer when eating food containing milk as an ingredient.