Rhinitis is a global health problem (1–4) and one of the most common chronic conditions in children (5). Several studies have provided compelling evidence that the prevalence of rhinitis is increasing, especially in children and young adults (1–4). Rhinitis is often undiagnosed (6), its prevalence underestimated and many patients fail to seek medical assistance.
Although usually not a severe disease, rhinitis may significantly impair the quality of life of patients (1, 7). It affects school performance, work productivity and has been recognized as a cause of absenteeism (1, 8, 9). Asthma and rhinitis are common co-morbidities amongst adults and older children, and are linked by epidemiological and patho-physiological characteristics and a common therapeutic approach (1).
Despite the recognition that rhinitis affects an increasing proportion of the paediatric population, at present there is a paucity of epidemiological data regarding its distribution, risk factors and natural history. Thus, in the current study we aimed to investigate the prevalence of symptoms suggestive of allergic rhinitis [using current rhinoconjunctivitis (CRC) as a marker] in preschool children in an epidemiological setting, within the context of a large prospective birth cohort study. In addition, we evaluated risk factors associated with the development of this phenotype during the first 5 years of life, its association with symptoms suggestive of other allergic diseases, and relationship with the objective measures of lung function and airway reactivity in preschool age.