The relationship of allergen-specific IgE levels and oral food challenge outcome.
BACKGROUND
Oral food challenges remain the gold standard for the diagnosis of food allergy. However, clear clinical and laboratory guidelines have not been firmly established to determine when oral challenges should be performed.


OBJECTIVE
We sought to determine the value of food-specific IgE levels in predicting challenge outcome.


METHODS
A retrospective chart review of 604 food challenges in 391 children was performed. All children had food-specific IgE levels measured by means of CAP-RAST before challenge. Data were analyzed to determine the relationship between food-specific IgE levels and challenge outcome, as well as the relationship between other clinical parameters and challenge outcome.


RESULTS
Forty-five percent of milk challenges were passed compared with 57% for egg, 59% for peanut, 67% for wheat, and 72% for soy. Specific IgE levels were higher among patients who failed challenges than among those who passed (P </=.03 for each food). When seeking a specific IgE level at which a 50% pass rate could be expected, a cutoff level of 2 kUA/L was determined for milk, egg, and peanut. Data were less clear for wheat and soy. Coexistent eczema or asthma was associated with failed egg challenges, but other atopic disease was otherwise not associated with challenge outcome.


CONCLUSIONS
Allergen-specific IgE concentrations to milk, egg, and peanut and, to a lesser extent, wheat and soy serve as useful predictors of challenge outcome and should be considered when selecting patients for oral challenge to these foods.
Perry
Tamara T
TT
Division of Allergy and Immunology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
Matsui
Elizabeth C
EC
Kay Conover-Walker
Mary
M
Wood
Robert A
RA
D000485:Allergens / Q000276:immunology; D002675:Child, Preschool; D003951:Diagnostic Errors; D019937:Diagnostic Techniques and Procedures; D005189:False Positive Reactions; D005260:Female; D005512:Food Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D012189:Retrospective Studies
D000485:Allergens; D007073:Immunoglobulin E