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Published on: May 31, 2021
Skin prick testing and peanut-specific IgE can predict peanut challenge outcomes in preschoolchildren with peanut
H Johannsen1, R Nolan, E M Pascoe
1School of Paediatrics and Child Health, University of Western Australia, Perth, Australia.
Insights
Many preschool children sensitized to peanuts can safely eat them. Skin prick tests and immunoassays help identify tolerance, reducing unnecessary avoidance diets.
Area of Science:
- Allergy and Immunology
- Pediatric Allergy
- Clinical Diagnostics
Background:
- Rising prevalence of peanut allergy presents a significant community health burden.
- Many preschool children are identified as peanut-sensitized during evaluations for other allergies.
- Current practice often involves prolonged avoidance diets for sensitized children with unknown clinical reactivity.
Purpose of the Study:
- To evaluate the effectiveness of skin prick tests (SPT) and fluorescent-enzyme immunoassays (FEIA) in diagnosing peanut allergy or tolerance.
- To identify reliable diagnostic markers for peanut sensitization in preschool children.
Main Methods:
- Forty-nine preschool children (<5 years) with peanut sensitization underwent graded open oral peanut challenges.
- Peanut sensitization was defined by SPT ≥ 2 mm or peanut-specific IgE ≥ 0.35 kU/L.
- A positive challenge indicated an objective IgE-mediated reaction during or within 2 hours of the challenge.
Main Results:
- Nearly half (49%) of the children experienced positive challenges, indicating allergy.
- SPT >7 mm predicted positive challenges with 83% sensitivity and 84% NPV.
- FEIA >2.0 kU/L showed 79% sensitivity and 80% NPV.
- Combining SPT and FEIA improved prediction to 96% sensitivity and 95% NPV.
Conclusions:
- At least 50% of preschool children with peanut sensitization can tolerate peanuts without prior ingestion history.
- SPT <7 mm and FEIA <2 kU/L effectively identify children likely to tolerate peanut, with a low (5%) failure rate on oral challenge.
- These findings aid clinicians in managing very young, peanut-sensitized children, potentially avoiding unnecessary dietary restrictions.
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%.
Conclusion And Clinical Relevance:
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.
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