Lactose intolerance is a common digestive problem that can result in a variety of uncomfortable, although short-lasting effects. However, these symptoms occur entirely in your digestive system. If you experience symptoms anywhere else in your body after drinking milk, you may have a milk allergy. A milk allergy is potentially much more severe than lactose intolerance, so you should see your doctor as soon as possible if you experience itching after drinking milk.
Lactose intolerance arises from your body producing too little lactase, the enzyme that breaks down lactose sugar during digestion. Because it's a digestive problem, all symptoms of lactose intolerance occur in your stomach and intestines. These include nausea, bloating, abdominal pain, gas and diarrhea. Although these symptoms can be severe, they usually last no more than a few hours after consuming lactose.
A milk allergy results from your immune system responding to milk proteins as if they are invaders, which can cause symptoms throughout your body, including itching and hives. Because a milk allergy may result in potentially life-threatening anaphylaxis, you should avoid milk products until seeing your doctor if you experience any symptoms of an allergic reaction.