Milk allergy and lactose intolerance are two very different issues related to the same food stuff. Milk allergy is generally an immune response to the protein found in milk which results in the immune system being stimulated and a reaction results such as an itch, rash, nausea, vomiting and breathing problems depending on the severity of the sensitivity and the number of times the person has been exposed. In general, an immune reaction gets more intense and more severe the more exposures. This type of reaction can be life threatening.