PURPOSE OF THE STUDY.
The purpose of this study was to evaluate familial behavioral patterns, clinical factors, and physician assessment by history and testing in siblings of peanut-allergic children.
Nine hundred and twenty-two siblings of peanut-allergic children who were part of the Canadian Peanut Allergy Registry (PAR) were evaluated by questionnaire between 2000 and 2012.
Parents completed questionnaires on siblings’ sociodemographic characteristics, exposure and reactions to peanut, confirmatory tests performed, and whether peanut allergy had been confirmed. Univariate and multivariate logistic regression models were used to estimate associations between characteristics of the index child and family and specific outcomes in the sibling.
All PAR families were surveyed (n = 932), and 80% of the families responded (n = 748). Of the peanut allergic siblings, 13.6% (n = 125/922, confidence interval [CI], 11.4%–16%) had never been exposed to peanut, 764 had been exposed, and 33 were uncertain. Among those never exposed, the majority (n = 88/125) was born after the diagnosis of peanut allergy (PNA) in the index child. Of the sibling group, 8.7% (n = 80/922, 95% CI 7.0–10.7) reported having been diagnosed with peanut allergy by a physician. Among these 80 children, 41 (51.3%) had reacted to peanut, 34 (42.5%) had never reacted, and in 5 children, the parents were not sure. Among those who had never reacted, 29 had a confirmatory test, and 5 were diagnosed without any history or testing. In the multivariate regression analysis including only siblings aged 3 years or older, siblings born after the diagnosis of peanut allergy in the index child were more likely to have never been exposed to peanut (odds ratio = 2.5, 95% CI, 1.1–6.9). In univariate analysis, siblings born after the PNA diagnosis in the index child were more likely to have been diagnosed as peanut allergic without a supportive history or confirmatory tests (odds ratio 12.7; 95% CI, 1.31–20.7).
More than 10% of siblings of PNA patients will avoid peanut. Siblings born after the diagnosis of PNA in the index child are more likely to have never been exposed. Educational programs are needed to prevent unnecessary avoidance.
Siblings of peanut-allergic children are reported to have an ∼7% risk of having a peanut allergy compared with 1% of children in general. A diagnosis of peanut allergy has a significant impact on quality of life, so an accurate diagnosis is imperative. Current National Institute of Allergy and Infectious Diseases guidelines state that there is no evidence for delaying introduction of any food beyond 6 months of age to prevent the development of allergy. Although parents of 1 allergic child often choose to minimize risk and anxiety by avoiding peanut altogether in subsequent children, delayed introduction of peanut may cause the siblings to “miss” the optimal timing for introduction of the protein and increase the likelihood of peanut allergy.
- Copyright © 2015 by the American Academy of Pediatrics