Milk allergy is one of the most common food allergies in children, but most children outgrow it by the age of 3. Although proteins in cow's milk are the usual cause of such an allergy, milk from goats, sheep and buffalo can also cause an allergic reaction.
Avoidance is the best treatment for milk allergy, but so many foods contain milk or milk products these days that people with the allergy have to pay close attention to just about everything they eat. An allergic reaction to milk typically occurs a few minutes to a few hours after consuming milk, and symptoms can include wheezing, vomiting, hives and digestive problems. Rarely, milk allergy can cause anaphylaxis.
A milk allergy is not the same as lactose intolerance — it's an allergy that involves the immune system whereas lactose intolerance involves the digestive system. People who are lactose intolerant don't produce enough of the enzyme to break down the sugar in milk.