Moderate-to-severe lower respiratory tract infection in early life is associated with increased risk of polysensitization and atopic dermatitis: Findings from the CHILD Study.

Background: Respiratory infections in infancy are associated with the development of allergic asthma and atopy. Delineating whether symptomatic infections are a marker of atopic predisposition or contribute to atopic development is important for preventive strategies. We hypothesized that early, severe lower respiratory tract infections (LRTIs) may be a risk factor for the development of atopic disease. Objective: Our aim was to determine whether clinically defined, moderate-to-severe LRTIs in infancy are associated with the development of atopic dermatitis and allergic sensitization at preschool age. Methods: LRTI timing and severity in the first 18 months of life was defined by using the Canadian Healthy Infant Longitudinal Development study questionnaires. Polysensitization and atopic dermatitis were determined by standardized skin prick testing and structured clinical assessments. Longitudinal associations between LRTI severity and clinical outcomes at ages 3 years and 5 years were determined by adjusted repeated measures generalized estimation equations. Results: Moderate-to-severe LRTIs were associated with increased odds of polysensitization (odds ratio = 1.91 [95% CI = 1.16-3.15]; Conclusions: These results highlight severe infant LRTI as an important risk factor for allergic and atopic disease (ie, polysensitization and atopic dermatitis), and they suggest that this risk is independent of maternal