Establishing the diagnosis of peanut allergy in children never exposed to peanut or with an uncertain history: a cross-Canada study.

ABSTRACT

The diagnosis of peanut allergy (PA) can be complex especially in children never exposed to peanut or with an uncertain history. The aim of the study is to determine which diagnostic algorithms are used by Canadian allergists in such children. Children 1-17 yrs old never exposed to peanut or with an uncertain history having an allergist-confirmed diagnosis of PA were recruited from the Montreal Children's Hospital (MCH) and allergy advocacy organizations. Data on their clinical history and confirmatory testing were compared to six diagnostic algorithms I. Skin prick test (SPT) >or=8 mm or specific IgE >or=5 kU/l or positive food challenge (+FC); II. SPT >or=8 or IgE >or=15 or +FC; III. SPT >or=13 or IgE >or=5 or +FC; IV. SPT >or=13 or IgE >or=15 or +FC; V. SPT >or=3 and IgE >or=5 or IgE >or=5 or +FC; VI. SPT >or=3 and IgE >or=15 or IgE >or=15 or +FC. Multivariate logistic regression analysis was used to identify factors associated with the use of each algorithm. Of 497 children recruited, 70% provided full data. The least stringent algorithm, algorithm I, was applied in 81.6% (95% CI, 77-85.6%) of children and the most stringent, algorithm VI, in 42.6% (95% CI, 37.2-48.1%).The factor most associated with the use of all algorithms was diagnosis made at the MCH in those never exposed to peanut. Other factors associated with the use of specific diagnostic algorithms were higher paternal education, longer disease duration, and the presence of hives, asthma, eczema, or other food allergies. Over 18% (95% CI, 14.4-23.0%) of children were diagnosed with PA without fulfilling even the least stringent diagnostic criteria.