That is a very good question. Milk allergy is an abnormal response by the body's immune system to milk and products containing milk. Cow's milk is the usual cause of milk allergy, but milk from sheep, goats and buffalo also can cause a reaction. Some children who are allergic to cow's milk are allergic to soy milk, too. Milk allergy is one of the most common food allergies in children. Avoidance is the primary treatment for milk allergy. Fortunately, most children outgrow a milk allergy by age 3.
Lactose intolerance, also called lactase deficiency, means you aren't able to fully digest the milk sugar (lactose) in dairy products. It's usually not dangerous, but symptoms of lactose intolerance can be uncomfortable. The problem behind lactose intolerance is a deficiency of lactase — an enzyme produced by the lining of your small intestine. You can control symptoms of lactose intolerance by carefully choosing a diet that limits dairy products.
Milk allergy and lactose intolerance are not the same thing. Lactose intolerance is not an allergy.There is no FDA definition for the terms "lactose free" or "lactose-reduced," a lactose-free product should not contain any lactose, and a lactose-reduced product should be one with a meaningful reduction. Therefore, the terms lactose-free and lactose-reduced have different meanings, and a lactose-reduced product may still contain lactose that could cause symptoms.
Soy based products contain soy protein and are made from soybeans. They do not contain any dairy.
Consult your pediatrician about your concerns that your baby may have inherited a milk allergy. Your pediatrician will advise you about what formula is best for your child.
Thank you for your question,