Cow's milk allergy: a critical review.

Foods which are ingested frequently, and cow's milk in particular, are a common cause of delayed-in-onset allergy. Difficulty in diagnosing milk allergy is encountered because: (1) skin tests are unreliable; (2) the symptoms of milk allergy are frequently delayed in appearing, thereby obscuring their connection with the previously ingested food; (3) when such symptoms do appear, they often fail to suggest allergy as etiologic; and (4) the offending antigen may be present in a milk product not obviously associated with milk per se such as sherbet or cheese. Contrary to common belief, most milk (and other food) allergy is not reagin (IgE) mediated. Milk allergy is not confined to infancy, but is frequently seen in children and adults, often persisting as an allergy which had supposedly been "outgrown." Since milk allergy is often a familial disorder, its presence in a patient can assist the physician in possibly discovering it in other members of the family. A two or three-week trial elimination of milk, in conjunction with written dietary instructions for the patient, is presently the only reliable diagnostic procedure.