Lactose intolerance is the responce of the digestive system. The person is unable to digest the sugars in milk.
Food intolerance vs. food allergy: What's the difference? From the Mayo Clinic Web site. http://www.mayoclinic.com/health/food-allergy/AN01109
Info, milk Production, Milk Marketing, and International Dairy Trading.
An allergy is an inappropriate immune responce to an allergen. The body reacts to the proteins found in milk or other food. Avoid all milk. Companies are allowd to "hide" milk in processing agents, food adatives and other means.
Reactions can varry person to person so much that diagnosis can be difficult. A person can have a sudden anaphilatic reation. One person can have heives another a gastral intestine reation minites or sometimes days later, though generally 20 minites to a couple hours later. Children with milk allergy don't always commuinicate an upset stomach, but don't gain weight or act sluggish or moody after consuming milk.
One would never offer "sugar free peanut butter" to a child who was allergic to peanuts. Someone who is allergic to peanuts is allergic to the peanut protein not the sugar in peanut products. Often people will think a person who is reactive to milk protein can have sugar reduced milk, commonly known as lactose free milk. A person who is reactive to the lactose or sugars in milk lack the enzymes to digest sugars in milk, so these products are created for these people, not for the Milk protein allergic.
Unlike nuts companies are allowed to put hidden milk in "milk free" products and often combine factory lines with products that are labelled milk free.
The RASP test, is a blood test that measures the IgE anti body measurement.