The natural history of allergic rhinitis in childhood.

The distinction between 'seasonal' and 'perennial' allergic rhinitis (AR) is not always adequate. The 'Allergic Rhinitis and its Impact on Asthma' (ARIA) work group suggested a new classification for AR based on severity and duration of symptoms. Our primary aim was to describe the natural history and burden of AR according to the new ARIA criteria in a population-based birth cohort study of children up to 13 yr. We defined symptoms as 'severe' (impairment of daily activities) or 'mild' (no impairment) and 'persistent' (duration > 1 month) or 'intermittent' (<or=1 month) using annual questionnaires. Serum immunoglobulin E to five common aero-allergens was determined at six time points. We analyzed complete follow-up data from 467 children (54% boys). The 12-month prevalence of AR quadrupled from 6% (at age 3 yr) to 24% (at age 13 yr) in children with non-allergic parents and more than tripled from 13% (3 yr) to 44% (13 yr) in children with at least one allergic parent. Half or more of the children with AR had 'severe persistent' symptoms. At age 13, these children were significantly more often sensitized than those with 'mild persistent' disease: 91% vs. 70% (p = 0.015). Sensitization to aero-allergens (adjusted OR 18.9; 95%CI 9.3-38.4) and having 2 parents with allergy (3.1; 1.1-9.3) were significantly associated with AR. According to the ARIA criteria, the impact of AR seems to be substantial; the vast majority of affected children suffered persistently for periods of 2 months or more annually, and most of the children with persistent AR were impaired in their daily activities.