The limited utility of the double-blind food challenge in diagnosing non-IgE mediated cow’s milk allergy in infants
Monday, March 5, 2018
South Hall A2 (Convention Center)
Kathleen G. Wallace, BA, Yamini V. Virkud, MD, Sarita U. Patil, MD, Joseph B. Leader, MD, Caroline Southwick, BA, Aubrey J. Katz, MD, Wayne G. Shreffler, MD PhD FAAAAI, Navneet K. Virk Hundal, MD
RATIONALE: Cow’s milk allergy (CMA) is the most common food allergy of infancy, most of which is non-IgE mediated. While the current gold standard of diagnosis of food allergy is the DBPCFC, it has not been evaluated for the diagnosis of non-IgE-mediated disease. We sought to evaluate its performance in non-IgE mediated disease using clinical intolerance of CMP formula as the gold-standard.

METHODS: Infants 18-120 days old with suspected CMA underwent a milk-free washout before the DBPCFC. Infants received 90ml of active (1.6g cow’s milk protein (CMP) + amino acid formula (AAF)) or placebo (AAF) formula daily for one week. After a one week washout, the process was repeated with the opposite formula. The Gastrointestinal Allergy Signs & Symptoms Instrument (GASSI) questionnaire was used to track symptom progression. Associations between baseline characteristics, GASSI scores and DBPCFC outcomes were evaluated by nonparametric statistical tests.

RESULTS: Thirty-five infants completed the DBPCFC. Twenty-eight of these infants failed to tolerate CMP-based formula. Of these, 18 (64%) were confirmed by DBPCFC, while 10 (36%) were not. No demographic factors or referral symptoms were associated with DBPCFC outcomes. The difference in GASSI scores between CMP and placebo treatment increased significantly between CMA and non-CMA infants (p=0.035).

CONCLUSIONS: One-third of infants with CMA are not identified by the 3-week DBPCFC and react at higher doses of CMP. High-threshold CMA infants have similar clinical presentations and demographics as non-CMA infants. Therefore, we propose a higher dose DBPCFC to increase the utility of this approach in the diagnosis of non-IgE CMA.