Cross‐sensitization profiles of edible nuts in a birch‐endemic area

• Published in: Allergy (Copenhagen) Vol. 71; no. 4; pp. 514 - 521
• Main Authors: Uotila, R., Kukkonen, A. K., Pelkonen, A. S., Mäkelä, M. J.
• Format: Journal Article
• Language: English
• Published: Denmark Blackwell Publishing Ltd 01.04.2016
• Subjects: Age Factors; Allergens - immunology; Allergies; Anacardium; Antigens, Plant - immunology; Arachis hypogaea; Betula - adverse effects; birch pollen; birch sensitization; Cluster Analysis; Corylus; Corylus - adverse effects; Cross Reactions - immunology; cross‐reactivity; Humans; Immunization; Juglans; nut hypersensitivity; Nut Hypersensitivity - diagnosis; Nut Hypersensitivity - epidemiology; Nut Hypersensitivity - immunology; Nuts; Nuts - adverse effects; oral allergy syndrome; Prevalence; Prunus dulcis; Skin Tests; birch sensitization; oral allergy syndrome; birch pollen; nut hypersensitivity; cross-reactivity
• ISSN: 0105-4538; 1398-9995
• DOI: 10.1111/all.12826

Background Sensitization to birch pollen causes cross‐sensitization to nuts, but rarely leads to clinical nut allergy. The aim was to study sensitizations to nuts in individuals sensitized to birch pollen and examine cross‐reactivities between birch and nut species. Methods All subjects with skin prick tests (SPTs) for birch pollen conducted during 1997–2013 in the Skin and Allergy Hospital in Helsinki (n = 114 572) and their available SPTs for nuts (n = 50 604) were included. Nut sensitizations were analyzed both with and without cosensitization to birch and stratified into age‐categories. Cross‐reactivities were analyzed with hierarchical clustering. One group of 1589 patients was surveyed for symptoms. Data were gathered also from Lapland to examine sensitizations in an area with less birch‐pollen exposure. Results Of subjects with birch sensitization, 84% were cosensitized to hazelnut, 71% to almond, and 60% to peanut. In a subgroup without birch sensitization, young children (<5 years) were most commonly nut‐sensitized (8–40%); and this prevalence decreased in adolescents and further in adults (4–12%). Cashew and pistachio (ρ = 0.66; P < 0.001) and pecan and walnut (ρ = 0.65; P < 0.001) correlated the strongest. The majority of nut‐sensitized patients (71% hazelnut, 83% almond, 73% peanut) reported no or mild symptoms. Cosensitizations between nuts and birch were similar in Lapland with its lower birch‐pollen exposure. Conclusion Birch‐sensitized individuals are frequently cosensitized to hazelnut, almond, and peanut. Among the birch‐negatives, prevalences of nut sensitizations decrease from early childhood to adolescence. Cashew and pistachio, and pecan and walnut cross‐react the most.