Is milk intolerance a food allergy or what?

Not allergy: Milk intolerance most commonly refers to a condition characterized by bloating, cramps and diarrhea caused by lactase deficiency without allergy/immune mechanisms involved. In allergy to cow's milk the immune system is reacting against cow's milk proteins causing symptoms such as hives. In infants, may cause blood in stools and constipation. The terms intolerance and allergy are often misused.