Allergy to cow’s milk is the most common food allergy in infants and young children. Symptoms of a milk allergy reaction can range from mild, such as hives, to severe, such as anaphylaxis. Therefore it is advised that people with milk allergy have quick access to an epinephrine auto-injector (such as an EpiPen®, Auvi-Q™ or Adrenaclick®) at all times. To prevent a reaction, strict avoidance of cow’s milk and cow’s milk products is essential. Always read ingredient labels to identify cow’s milk ingredients.
Approximately 2.5 percent of children younger than three years of age are allergic to milk. While their are alternatives in Almond and Soy addressing the original allergy can reduce sensitivities or attacks in schools, play dates and children just being children.
There are also significate differences between a Milk Allergy and a Lactose Allergy.
https://www.foodallergy.org/allergens/milk-allergy