An allergy is a sign that your immune system is prone to making mistakes. When certain harmless substances enter your system, your body misidentifies them as dangerous and sends out a team to neutralize them. First on the scene is the antibody immunoglobulin E, which then calls for mast cell back-up. The mast cells bring in a swarm of chemicals, and you suffer the allergic symptom fallout. If you have a milk allergy, there's a good chance your body will make more mistakes and you'll end up with other allergies, like skin allergies. Plus, people who already have atopic dermatitis (which is a type of eczema) are more at risk for milk allergies. In addition, some of the symptoms of a milk allergy appear on your skin, including hives, rashes and swelling. So milk allergies can definitely be related to skin allergies and symptoms.
Dairy allergies are often the first allergies that a child develops; they're most common in infants. Kids tend to outgrow allergies to milk by the time they're three years old. But until the allergy is gone, the best way to prevent allergic reactions is to keep your child away from dairy products. For future reference, some studies show that if an infant is breastfed for the first four months of his life, he won't develop a milk allergy. For those babies that already have a milk allergy, breast milk is still safe, although some babies might react if milk you drink is passed on to them. The problem is cow's milk. There are also some hypoallergenic baby formulas in which milk proteins are broken down to levels that are safe for allergic infants to drink.
It's important to differentiate between a milk allergy and lactose intolerance, however. While a milk allergy involves your immune system, lactose intolerance is a digestive problem. Lactose intolerance is much more likely to affect adults than milk allergies.