Journal of Allergy and Clinical Immunology
Change in Peanut Skin Prick Testing Over Time in Infants at Risk for Food Allergy Who Continue to Avoid Peanut
Section snippets
Rationale
Current guidelines recommend early peanut introduction to all infants, with physician supervised introduction for those with skin prick test (SPT) 3-8mm. Many of these infants will have supervised introduction deferred to a subsequent visit and some never return for follow-up. It is currently unknown if and how peanut SPT results change over time in infants.
Methods
We performed a 5-year retrospective review of all infants who had peanut SPTs placed at two separate time points during the first 24 months of life. Infants at risk of peanut allergy were defined as having a history of atopic dermatitis and/or any other food allergy. Infants were excluded if they had ingested peanut prior to either SPT. The Wilcoxon signed-rank test was used to compare the differences between the distributions of wheal size at both tests, paired for each patient.
Results
Among the 51 infants at risk for peanut allergy, there was a significant difference between the first and second SPT with an average increase of 1.6mm (mean duration between SPTs=5.8 months, p=0.006). This difference increased to an average of 2mm (p=0.001) when excluding 7 infants who had an initial SPT of ≥8mm. Sub-group analysis showed no significant changes in SPT associated with differences in gender, ethnicity, eczema severity, or time between SPTs.
Conclusions
Peanut SPT size can increase over time in infants at risk for peanut allergy who are avoiding peanut. This supports the need for timely introduction of peanut into the diet of infants with SPTs <8mm.