Does allergic rhinitis exist in infancy? Findings from the PARIS birth cohort.

BACKGROUND: Early onset of allergic rhinitis (AR) is poorly described, and rhinitis symptoms are often attributed to infections. This study analyses the relations between AR-like symptoms and atopy in infancy in the PARIS (Pollution and Asthma Risk: an Infant Study) birth cohort. METHODS: Data on AR-like symptoms (runny nose, blocked nose, sneezing apart from a cold) were collected using a standardized questionnaire administered during the health examination at age 18 months included in the follow-up of the PARIS birth cohort. Parental history of allergy and children's atopy blood markers (blood eosinophilia ≥470 eosinophils/mm(3) , total immunoglobulin E ≥45 U/ml and presence of allergen-specific IgE) were assessed. Associations were studied using multivariate logistic regression models adjusted for potential confounders. RESULTS: Prevalence of AR-like symptoms in the past year was 9.1% of the 1850 toddlers of the study cohort. AR-like symptoms and dry cough apart from a cold were frequent comorbid conditions. Parental history of AR in both parents increased the risk of suffering from AR-like symptoms with an OR 2.09 (P=0.036). Significant associations were found with the presence of concurrent biological markers of atopy, especially blood eosinophilia and sensitization to house dust mite (OR 1.54, P=0.046 and OR 2.91, P=0.042) whereas there was no relation with sensitization to food. CONCLUSIONS: These results support the hypothesis that AR could begin as early as 18 months of life. Suspicion of AR should be reinforced in infants with parental history of AR or biological evidence of atopy, particularly blood eosinophilia and sensitization to inhalant allergens.