Pine nut allergy in Korean children: Clinical characteristics and diagnostic values of specific IgE against pine nuts

Abstract Background Hypersensitivity reactions to pine nuts in children have been occasionally encountered recently, although reports on pine nut allergy cases are rare worldwide. The study aimed to feature clinical and laboratory findings pertaining to pine nut allergy in Korean children. Methods Forty-two subjects were enrolled through a retrospective review of medical records, from September 2010 to December 2015, at the Department of Pediatrics in Ajou University Hospital. The demographic profiles, clinical characteristics, and laboratory findings were evaluated. Results Twenty-four patients showed immediate-type reactions after exposure to pine nuts (the allergic group), while the remaining 18 were atopic controls, who exhibited no allergic symptoms (the tolerant group). The median age of the subjects in the allergic group was three years. More than half of the subjects in this group experienced allergic symptoms within 5 min, and seven of them experienced anaphylaxis. The median level of pine nut-specific immunoglobulin E (sIgE) in the allergic group (1.62 kU A /L) was significantly higher ( p  = 0.014) than that in the tolerant group (0.11 kU A /L), with an optimal cut-off level of 0.40 kU A /L (sensitivity, 66.7% and specificity, 77.8%). The positive decision point of pine nut-sIgE (specificity, 100%) to distinguish the allergic and tolerant groups was 2.84 kU A /L. However, there was no difference in pine nut-sIgE levels between the anaphylaxis and non-anaphylaxis cases. Conclusion About 30% of children with pine nut allergy experienced anaphylaxis. The optimal cut-off level of pine nut-sIgE to distinguish the allergic and tolerant groups was 0.40 kU A /L and the positive decision point was 2.84 kU A /L.