[Single blind food challenge using dried food powder --2nd Report. milk]

We analyzed data obtained from cow's milk challenge with single-blind manner in our department.

We have performed 83 cow's milk challenges in the hospital from 1995 to 2005, and patient profiles and results of the challenges were analyzed.

Positive rate of cow's milk challenges were 44.6% (37/83), and evoked symptoms by cow's milk challenges were most frequently seen in skin, followed by respiratory tract, and gastrointestinal system. Cases of anaphylaxis were seen in 8.1%. Seventy six percentages of symptoms started within one hour after the challenge, and 56.8% among positive cases were medicated. Adrenaline was injected in 9 cases out of 37 positive challenge cases. And all anaphylaxis patients recovered. We performed 19 open challenges with heated-cow's milk among 37 positive cases, and only one negative case existed. When we compared profiles of negative cow's milk challenges and positive ones, significant higher rate on positive skin prick tests (SPT) against cow's milk and complication of bronchial asthma were recognized in positive group. Sensitivity of SPT was 97.3% and specificity was 17.4%. Sensitivity of IgE CAP-RAST was 100% and specificity was 15.2%.

Single-blinded challenge tests were safe. And they were useful in judgment of the acquisition of oral tolerance in cow's milk allergy. It was only one case that effect of the heating un-matched in food provocation test results. Although we experienced fairly high prevalence of respiratory symptoms during cow's milk challenge tests, appropriate medication especially adrenaline introduction made our test safe enough.