What Is a Milk Allergy?
Milk allergy usually first occurs when infants are given cow’s milk-based formula or are exposed to cow’s milk in the mother’s diet through her breast milk. Between 2% and 3% of babies and toddlers are affected by milk allergy. Milk contains proteins, carbohydrates (such as sugars), fats, minerals, and vitamins. Casein is the principal protein in cow’s milk, accounting for about 80% of the total milk proteins. Casein is what makes up the curd that forms when milk is left to sour. The remaining 20% of cow’s milk proteins are contained in the whey, the watery part that’s left after the curd is removed. The proteins in milk are what cause allergic reactions in some people. A person may be allergic to proteins in either the casein or the whey parts of milk and sometimes even to both. There are two major types of milk allergy reactions: rapid onset and slower onset. The rapid type of reaction comes on suddenly (within seconds to hours after ingesting the milk or milk product) with symptoms
