Pets, furry animal allergen components, and asthma in childhood

Background: The use of component-resolved allergy diagnostics has provided a clearer understanding of the species-specific sensitization and severity of potential allergic reactions. This cross-sectional study aimed to determine whether sensitization to allergen components in furry animals is indicative of blood eosinophilia, a positive fractional exhaled nitric oxide (FeNO) test, abnormal lung function, and asthma symptoms in children. Additionally, we investigated whether having pets during childhood affects the development of asthma or allergic sensitization to furry animals. Methods: We recruited 203 children aged 4-17 years with asthma diagnosis based on abnormal lung function and 33 controls. IgE-sensitization to allergen components for dogs, cats, and horses was analyzed using a multiplex microarray. Children were tested with FeNO, impulse oscillometry, spirometry, methacholine challenge, and skin prick test. A questionnaire was used to investigate pet ownership and symptom profile. Results: FeNO results and blood eosinophilia revealed a correlation with sensitization to all furry animal allergens, particularly lipocalins (r = 0.203-0.560 and 0.206-0.560, respectively). Can f 3 was found to correlate with baseline R5 (r = 0.298). No association between methacholine challenge results and sensitization to furry animal allergens was found. Children with asthma who were sensitized to Can f 1, Can f 6, or both frequently reported asthma symptoms. Dog ownership was associated with a lower level of IgE-sensitization to lipocalins, fewer asthma symptoms, and less blood eosinophilia. Conclusion: Furry animal allergen component IgE-sensitization is a risk factor for type 2-inflammation and asthma symptoms.