Prather Pediatric and Allergy Center - Ask Doctor Brent

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Title: Cow's Milk is the Most Common Cause of Food Allergy

Category: Asthma and Allergy


Recently a large collaborative study was done in Melbourne, Australia by Dr. David Hill along with Dr. Bjorksten from Sweden and Dr. Allen Walker from Harvard. Dr. Walker summarized their findings in the Summer Harvard Newsletter. They concluded that cows milk is the most common cause of food allergies particularly in infants and children. This is something we have always known and is not a surprise. They did try to separate out groups of people according to probability of having true allergy. They distinguished between adverse reactions to food which is a general term and can be caused from sugars and food additives and have nothing to do with true allergies which always occurs from proteins. They broke down the nature of allergic reactions to foods into three major categories: high probability, moderate probability and low probability. Under the high probability of cows milk allergy as the cause of symptoms was anaphylaxis, urticaria, angioedema, eczema, vomiting and diarrhea. These reactions usually occurred within minutes of ingesting milk. I had a patient who had cows milk anaphylaxis as an infant and small child and would get pale and weak and require adrenalin shots every time she ingested even the amount of milk in one or two cookies or a piece of cake at another child's birthday party. She is now a healthy teenager, President of her junior high school and no longer has any trouble with milk products. Her story is typical in that most patients who have milk allergy, even severe milk allergy in infancy, usually outgrow it as they get older.

Under moderate probability were eczema, colic, failure to thrive with chronic GI symptoms, and inflammatory bowel diseaselike syndromes (colitis, eosinophilic enteropathy, breast milk colitis).

Out of the hundreds of cases of eczema patients I see, however, I rarely find one who improves on cow milk avoidance. Nevertheless, it is worth trying and if there is a history of difficulty with cow milk proteins it should always be tried for at least a few weeks. Colic is a nebulous diagnosis which probably has many causes. Many studies do link it to cow milk protein allergy. It is probably worth a trial on a cow milk protein-free formula for a very colicky baby, again, for at least a week or two. Rarer things like colitis which can be caused from allergy to cow milk proteins would need the help of a pediatric gastroenterologist to do biopsies and sophisticated studies to make a proper diagnosis. Fortunately, these are exceedingly rare.

Under low probability, Dr. Walker and his colleagues summarized chronic rhinorrhea or chronic clear runny nose and nasal obstruction. Also, recurrent middle ear disease or fluid in the middle ear was rarely associated with cow milk allergy. Recurrent cough and asthma was rarely caused from cow milk allergy. These single system diseases developing in the second or third year of life (after having tolerated cows milk for years before) are rarely caused by a sudden onset of cow milk allergy.

If your child has any of these diagnoses and you suspect cow milk allergy, discuss it with your physician who can recommend eliminating cow milk from the diet for two to four weeks. Then, challenging with cow milk either in the office or at home under careful conditions. Occasionally, skin testing to cow milk can be helpful and there are blood tests such as Rast tests which can also help to diagnose milk allergy. Just about all of the findings and diagnoses associated with cow milk can also be associated with other milk contents such as casein and whey which are now being used in some of the new formulas. These milk induced allergy diseases are similarly found and connected with other high allergy foods including egg, soy, wheat and casein hydrolysate and whey hydrolysate formulas.

It is important to sort out true allergy from symptoms and diseases not associated with allergy for many reasons. One is that it is terrible to restrict foods from a child's diet which they are not allergic to and possibly limit important nutrients which they need. Discuss these confusing and complicated issues with your doctor if you feel your child has any of these things and also be sure your child is getting an adequate amount of calories, calcium and vitamins. Fortunately, milk allergy and most other food allergies are usually outgrown over time and about once a year it is safe to challenge with the suspected food in a very careful setting such as your doctor's office.