Cow's milk allergy is one of the most common food allergies. Cow's milk allergy affects about 2% of young children, but is rare in adults. In up to 60-70% of affected children, there is a tolerance to well-cooked forms of milk in foods such as cakes, muffins and cookies. Your doctor may discuss this with you.
What are the reactions associated with milk?
The term allergy to milk corresponds to immediate reactions to milk which involve IgE antibodies, and that are characterized by skin, respiratory, digestive and sometimes cardiovascular symptoms (see the section on Food allergy). Other reactions involving the immune system and particularly the gastrointestinal tract are related to milk (see the section on Food related enteropathies). Finally, certain reactions to milk do not involve the immune system at all. For example, lactose intolerance is relatively frequent, but is not an allergy. It is caused by the absence of an enzyme necessary to digest lactose contained in milk and milk products. It is characterized by abdominal pain, bloating and diarrhea.
How does one avoid milk?
As for most other food allergies, treatment always begins with avoidance. In addition to informing those around you and taking precautions to avoid contamination, you must attentively read all food labels, since the milk protein can be found in many different foods. Other names can be used to designate milk: casein, lactalbumin, lactate, lactose, lactoglobulin, lactoferrin, modified milk ingredients, etc. (see the site of the Canadian Food Inspection Agency for a more exhaustive list). In Canada, a law mandates that the word "milk" is clearly indicated in the list of ingredients. When milk is avoided, you must ensure that the elements of nutritional value of milk, in particular the daily requirements for calcium and vitamin D, are provided for by other foods in the diet. Growth must be followed closely. A consultation by a nutritionist may be recommended by your doctor.
What is the evolution of an allergy to milk?
In the majority of cases, an allergy to milk disappears, often before school age.
Nha Uyen Nguyen-Luu, MD FRCP
(translation: Andrew Moore, MD FRCPC)