title: Use of Specific IgE and Skin Prick Test to Determine Clinical Reaction Severity.
abstract: AIMS: To determine whether specific IgE and skin prick test correlate better in predicting reaction severity during a double-blinded placebo controlled food challenge (DBPCFC) for egg, milk, and multiple tree nut allergens.  STUDY DESIGN: Prospective study.  PLACE AND DURATION OF STUDY: Department of Pediatrics, Stanford University School of Medicine, August 2009 and ongoing.  METHODOLOGY: We examined the reaction severity of twenty-four subjects to nine possible food allergens: milk, egg, almond, cashew, hazelnut, peanut, sesame, pecan and walnut. Specific IgE and SPT were performed before each DBPCFC. DBPCFC results were classified into mild (1), moderate (2), or severe (3) reactions using a modified Bock's criteria.  RESULTS: Twenty four subjects underwent a total of 80 DBPCFC. Eighty percent of all DBPCFCs resulted in a positive reaction. A majority, 71%, were classified as mild. No reactions occurred with a SPT of zero mm while three reactions occurred with a negative specific IgE. All reactions were reversible with medication.  CONCLUSION: These data suggest that SPT and specific IgE levels are not associated with reaction severity (p<0.64 and 0.27, respectively). We also found that combining specific IgE and SPT improved specificity but did not help to achieve clinically useful sensitivity. For instance, an SPT > 5mm had a sensitivity of 91% and specificity of 50%. Combining SPT > 5mm and IgE > 7 resulted in a reduced sensitivity of 64%. Unexpectedly, a history of anaphylaxis 70% (n=17) was not predictive of anaphylaxis on challenge 4% (n=2).
authors.affiliation: 2351 Clay Street, Suite 380, San Francisco, CA 94115, Department of Internal Medicine, California Pacific Medical Center, California, United States.
authors.forename: Von
authors.initials: V
authors.lastname: Ta
authors.forename: Brittany
authors.initials: B
authors.lastname: Weldon
authors.forename: Grace
authors.initials: G
authors.lastname: Yu
authors.forename: Olivier
authors.initials: O
authors.lastname: Humblet
authors.forename: Susan
authors.initials: S
authors.lastname: Neale-May
authors.forename: Kari
authors.initials: K
authors.lastname: Nadeau