Onset of Nut Allergy in a Pediatric Cohort: Clinical and Molecular Patterns in the AFRUSEN Study

AFRUSEN Task Force, Pediatric Allergy Committee, Spanish Society of Allergy and Clinical Immunology (SEAIC)

Research output: Contribution to journalArticlepeer-review


Background: Nut allergy is a growing problem, yet little is known about its onset in children. Objective: To characterize the onset of nut allergy in children in southern Europe. Methods: The study population comprised consecutive patients up to 14 years of age who visited allergy departments with an initial allergic reaction to peanut, tree nut, or seed. The allergy work-up included a clinical history, food challenge, skin prick testing, determination of whole-extract sIgE, and ImmunoCAP ISAC-112 assay. Results: Of the 271 children included, 260 were first diagnosed with nut allergy at a mean age of 6.5 years and at a mean (SD) of 11.8 (21.2) months after the index reaction. The most common culprit nuts at onset were walnut (36.5%), peanut (28.5%), cashew (10.4%), hazelnut (8.5%), pistachio (5.4%), and almond (5%). Onset of peanut allergy was more frequent in children ≤6 years and walnut in those aged >6 years (P=.032). In 65% of cases, the allergic reaction occurred the first time the patient consumed the nut, and 35% of reactions were anaphylactic. Overall, polysensitization to nuts was detected by skin prick testing in 64.9% of patients, although this rate was lower among walnut-allergic children (54.7%) and peanut-allergic children (54.1%) (P< .0001). Sensitization to 2S albumins was predominant (75%), especially Jug r 1 (52.8%), whereas sensitization to lipid transfer proteins was less relevant (37%). Conclusion: In the population we assessed, the onset of nut allergy occurred around 6 years of age, slightly later than that reported in English-speaking countries. Walnut was the main trigger, followed by peanut. 2S albumin storage proteins, especially Jug r 1, were the most relevant allergens. This study will help guide management and may contribute to preventive strategies in pediatric nut allergy.

Original languageEnglish
Pages (from-to)270-281
Number of pages12
JournalJournal of Investigational Allergology and Clinical Immunology
Issue number4
StatePublished - 2022
Externally publishedYes


  • Alergia a alimentos.
  • Alergia a fruto seco
  • Allergy onset
  • Anafilaxia
  • Anaphylaxis
  • Cacahuete
  • Component-resolved diagnosis
  • Debut de alergia
  • Diagnóstico por componentes
  • Food allergy
  • Nuez
  • Nut allergy
  • Peanut
  • Perfil de sensibilización
  • Sensitization profile
  • Walnut


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