title: Skin prick testing and peanut-specific IgE can predict peanut challenge outcomes in preschoolchildren with peanut sensitization.
abstract: BACKGROUND
  The rise in peanut allergy is a source of considerable burden in the community. A growing number of preschoolchildren have been identified as peanut sensitized in the course of investigation of other allergic conditions. Although many have never knowingly ingested peanuts and their clinical reactivity is not known, it has been common practice to place these children on avoidance diets for many years.
  
  
  OBJECTIVE
  To determine the utility of skin prick tests (SPT) and fluorescent-enzyme immunoassays (FEIA) for identifying either peanut allergy or tolerance in preschoolchildren with peanut sensitization.
  
  
  METHODS
  Forty-nine preschoolchildren (<5 years of age) with peanut sensitization (SPT ≥ 2 mm or peanut-specific IgE ≥ 0.35 kU/L) but unknown clinical reactivity had graded open peanut challenges reaching a total of 11 g. A positive challenge was defined as an objective IgE-mediated reaction during challenge or the 2-h observation.
  
  
  RESULTS
  Forty-nine percent (24/49) of children had positive challenges. An SPT of >7 mm on the day of challenge predicted a positive challenge with a sensitivity of 83% and a negative predictive value (NPV) of 84%. An FEIA of >2.0 kU/L showed a sensitivity of 79% and an NPV of 80%. Predicting challenge outcome from a combination of SPT and FEIA (SPT >7 and/or FEIA >2 is positive) increased sensitivity to 96% and NPV to 95%.
  
  
  CONCLUSIONS
  At least half of preschoolchildren with peanut sensitization and no antecedent history of peanut ingestion can tolerate peanuts. A SPT<7 mm and FEIA<2 kU/L identify children most likely to tolerate peanut, with only a 5% likelihood of failing an oral challenge. This study assists clinicians considering challenges in very young peanut-sensitized children.
authors.affiliation: School of Paediatrics and Child Health, University of Western Australia, Perth, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Johannsen
authors.forename: R
authors.initials: R
authors.lastname: Nolan
authors.forename: E M
authors.initials: EM
authors.lastname: Pascoe
authors.forename: P
authors.initials: P
authors.lastname: Cuthbert
authors.forename: V
authors.initials: V
authors.lastname: Noble
authors.forename: T
authors.initials: T
authors.lastname: Corderoy
authors.forename: A
authors.initials: A
authors.lastname: Franzmann
authors.forename: R
authors.initials: R
authors.lastname: Loh
authors.forename: S L
authors.initials: SL
authors.lastname: Prescott
mesh_terms: D000918:Antibody Specificity; D010367:Arachis / Q000276:immunology*; D002675:Child, Preschool; D006801:Humans; D007108:Immune Tolerance; D007124:Immunoenzyme Techniques / Q000379:methods; D007073:Immunoglobulin E / Q000097:blood*; D007223:Infant; D021183:Peanut Hypersensitivity / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D011237:Predictive Value of Tests; D012882:Skin Tests; D016896:Treatment Outcome
chemical_list: D007073:Immunoglobulin E