Furry Animal Allergen Component Sensitization and Clinical Outcomes in Adult Asthma and Rhinitis

Background Sensitization to allergen components has been linked to asthma in children, but studies in adults are lacking. Objective To study the relation of sensitization to furry animal allergen components to risk of asthma, rhinitis, and markers of asthma severity in adults. Methods From the West Sweden Asthma Study, a random population-representative sample of adults aged 16 to 75 years, 2006 participants were clinically examined; 1872 were analyzed for serum IgE level to a mix of aeroallergens. Those with an IgE level of more than 0.35 kU A /L to cat, dog, or horse allergen components were analyzed for specific cat ( Felis domesticus [Fel d 1, Fel d 2, and Fel d 4]), dog ( Canis familiaris [Can f 1, Can f 2, Can f 3, and Can f 5]), and horse ( Equus caballus [Equ c 1]) allergen components. We defined monosensitization, double sensitization, and polysensitization (>2 components) patterns and applied cluster analysis to derive distinct sensitization clusters. Results Sensitization to each allergen component, lipocalins, each sensitization pattern, and each sensitization cluster (nonsensitized, Fel d 1–driven sensitized, and multisensitized clusters) was associated with substantial increased risk of asthma, rhinitis, concomitant asthma and rhinitis, and Asthma Control Test–controlled asthma. Fel d 1, Can f 1, Can f 2, Can f 3, polysensitization, and multisensitized cluster were further associated with increased fractional exhaled nitric oxide and eosinophil levels, but with lower PD 20 methacoline (provocative dose of methacholine causing a 20% drop in FEV 1 ) values. There was no association with asthma exacerbations, FEV 1 predicted values, emergency visits or regular oral steroid use, and neutrophil levels. Conclusions Sensitization to furry animal allergen components is an important predictor of asthma, rhinitis, and markers of asthma severity with increased blood eosinophils, fractional exhaled nitric oxide, and airway hyperreactivity.