Cross-Sensitization Between Sesame and Other Seeds in Children

To describe characteristics of sesame-sensitized/allergic children and evaluate cross-sensitization patterns with other edible seeds.The study included 79 sesame-sensitized children (mean age 6.5 years, SD ±4.2 years) determined by positive prick-by-prick (PbP) skin test in the allergy unit of a children’s hospital in Florence, Italy. This cohort included children with a history of sesame allergic reaction with varying severity (n = 55, 69.6%) and those with no history of reaction but practicing avoidance (n = 24, 30.4%). Although a subset had confirmed or ruled-out sesame allergy by oral food challenge (OFC), a majority did not undergo OFC testing.This retrospective cohort study examined children sensitized to sesame based on PbP wheal size and serum-specific immunoglobulin E (sIgE) levels. Participants were evaluated for cross-sensitization to flax, sunflower, and pumpkin seeds based on PbP and sIgE. Immunoblot analysis of sera further investigated seed cross-sensitization patterns.Children with a history of sesame-induced anaphylaxis had significantly larger wheal diameters compared with those with a history of mild to moderate reaction. There was no difference in sesame sIgE levels. Among sesame-sensitized patients, the rates of cross-sensitization were 52.9% to flax, 51.4% to sunflower, and 45.6% to pumpkin seeds. Sera from this cohort showed in vitro cross-reactivity to multiple seeds. Among the shared allergenic proteins, sesame 11S and 7S globulins displayed the highest reactivity. Sesame-sunflower-flax and sesame-sunflower-pumpkin emerged as the most likely cross-sensitized seed combinations.A high rate of cross-sensitization was reported among sesame, flax, sunflower, and pumpkin seeds. 11S and 7S globulins were the main contributors to cross-reactivity on immunoblot and may play a key role in seed cross-sensitization.Sesame allergy is a growing global concern. In 2023, sesame was recognized as the ninth major food allergen requiring mandatory labeling in the United States. This Italian pediatric cohort describes a heterogeneous group of sesame-sensitized and -allergic children. Further studies need to confirm cross-sensitization rates between seeds in sensitized vs allergic patients as well as explore relevance to clinical cross-reactivity through OFCs.