If you are unable to eat dairy products, drinking milk can cause a variety of symptoms, from an upset stomach to headaches. Although most people assume that these are a sign of lactose intolerance, in fact another condition, known as milk allergies, may be behind the reaction.
Lactose intolerance means that your body lacks a needed enzyme, lactase. This enzyme digests lactose, a sugar found in milk. Without this enzyme, your body is unable to process the sugar in milk. The symptoms caused by this tend to be gastrointestinal in nature. If you can drink small quantities of milk, and only experience a reaction when you consume larger quantities, it is likely lactose intolerance, not a milk allergy.
Milk allergies, meanwhile, involve an immune system response against milk. Your immune system mistakenly identifies milk proteins as a threat, making antibodies against them. The milk allergy may be a reaction to casein or to whey, two proteins found in milk. Those with milk allergies usually experience a reaction even with a very small amount of milk, and the symptoms tend to be more wide-ranging than those seen with lactose intolerance, including symptoms affecting the skin and respiratory tract.
Although the symptoms of both conditions are similar, it is important to determine which of these conditions you have ,as the treatment is different. Those with lactose intolerance can usually consume some milk after taking pills containing lactase. However, there is no comparable way for those with a milk allergy to avoid a reaction, and they must avoid consuming milk in any quantity.
The only sure way to determine whether you have lactose intolerance or a milk allergy is to visit your doctor for a blood test. If you suspect that your symptoms are caused by consuming milk, contact your doctor, and consider eliminating milk from your diet to see if your symptoms improve.