In lactose intolerance, depending on the individual, a negative response to lactose will often depend on how much lactose he or she consumes. In many cases, cutting out obvious sources of lactose like milk, cheese or yogurt, or turning to lactose-free alternatives, will avoid problems. In other cases, the person needs to avoid all lactose.
In milk allergy, cutting the obvious is not enough. Any dairy product, even if labeled “lactose-free,” can set off reactions. Lactose-free does not mean dairy-free. Lactose-free items are often crammed with milk proteins. In addition, many baked goods and processed foods have dairy components. This dairy often comes in the form of whey protein, a concentrated dairy extract that can cause a severe reaction in someone with a milk allergy.