Need clarification: what is the difference between lactose intolerance and milk allergy?

Allergy/intolerance: Allergy is an over reaction of the immune system to a normally harmless substance while an intolerance usually mean you cannot digest the food properly. In lactose intolerance you are missing the enzyme to digest lactose in dairy products resulting in GI symptoms.

Enzyme and immunity: Lactose intolerance is due to a lack of lactase to break down the lactose thereby allowing it to get down to the large intestine where the bacteria start to use it leading to gas and diarrhea this may be corrected by taking lactase tablets ahead of time.Milk allergy is an allergic reaction. Often involves other systems . The only treatment is avoidance. Cooked product ok for 1/2 of the sufferers.