Sensitization to dog and cat allergen components and allergic symptoms among adolescents in Northern Sweden

<bold>Background:</bold> Tests for dog and cat allergen components are available and needs to be further evaluated. <bold>Aim:</bold> To describe prevalence of sensitization to cat and dog components and the association with asthma and rhinoconjunctivitis (RC). <bold>Methods:</bold> In a random sample from a population-based cohort aged 19 years, 595 subjects were tested for sensitization to airborne allergens using ImmunoCAP. Subjects with IgE levels > 0.10 kU/L to cat, dog or horse were further analyzed by microarray (ImmunoCAP™ISAC 112) including components for dog: Can f 1-6 and cat: Fel d 1, 2 and 4. Fel d 7 was analyzed with ImmunoCAP™. Information about symptoms upon cat and dog exposure were obtained by a structured interview. <bold>Results:</bold> The most prevalent (51.6%) dog component was Can f 5. Among the 26.5% of dog-sensitized subjects who were negative to all tested dog components, the prevalence of asthma upon dog contact was 0.9%. This increased from 6.7% in subjects sensitized to one component to 40% in subjects sensitized to all six components. The prevalence of RC was higher among subjects sensitized to lipocalins and Can f 5 than among subjects sensitized to only lipocalins. This difference was not seen for asthma symptoms. The most prevalent (91.2%) cat component was Fel d 1. In subjects sensitized to all four cat components the prevalence of RC was 100%. <bold>Conclusion:</bold> The prevalence of allergic symptoms increased with the number of sensitizing allergen components. Individuals sensitized to dog had more complex component sensitization patterns compared to those sensitized to cat. Sensitization to Can f 5 had an impact on RC but not on asthma in subjects sensitized to dog lipocalins.