The importance of appropriate challenges in diagnosing food sensitivity

Two patients with clinically significant immunoglobulin E (IgE) mediated reactions to cow's milk which occur only under special circumstances are described. Although double-blind, placebo-controlled food challenges or open food challenges are generally very helpful, certain patients who react only under special circumstances might be missed when these office tests are used. The two reported incidences occurred in older children who seemed to outgrow their cow-milk allergy but still had clinically significant allergic reactions under certain circumstances.