Many times the terms “milk allergy” and “lactose intolerance” are used interchangeably, creating confusion among people. However, they are different health conditions with different causes, symptoms, target groups and different treatments are needed to offset their effects. It is therefore imperative to outline the differences between these two terms.

On one hand, when we talk about “food intolerance,” we refer to an adverse reaction of the body to a food substance or additive that involves digestion or metabolism (breakdown of food by the body) but does not involve the immune system. Lactose intolerance is an example of this. It occurs when a person lacks the enzyme (lactase) needed to digest milk sugar (lactose).

On the other hand, “food allergy” is a reaction of the body's immune system to something in a food or an ingredient in a food –usually a protein. Cow's milk, eggs, wheat, and soy are among the most common sources of food allergies in children. Milk allergy is caused by an abnormal reaction of the immune system to the proteins present in milk.

Furthermore, the symptoms of milk allergy and lactose intolerance can take many forms, and many times they differ greatly among individuals. In cow's milk allergy, the effects can be immediate or delayed, and symptoms will appear throughout the body. The sites mostly affected are the digestive tract (nausea, stomach cramps, vomiting, diarrhoea), the skin (hives, eczema, swelling), and the airways (wheezing, runny nose, nasal congestion, coughing). One of the greatest dangers in food allergies comes from anaphylaxis, which in this case may be rare, acute or even sometimes produce an overwhelming reaction of the immune system. For some people, cow's milk allergy might cause only hives or an upset stomach; for others, however, it can lead to serious illness or even death (life threatening).

Lactose intolerance may produce symptoms similar to cow's milk allergy, such as diarrhoea, vomiting and/or stomach cramps; however, it can result in abdominal bloating and gas production. The severity of symptoms varies depending on the amount of lactose each individual can tolerate.