title: [Epidemiology of allergic respiratory disorders in infants].
abstract: BACKGROUND
  Allergic disorders of the respiratory tract have been the subject of many epidemiological studies, especially during infancy which is known to be a critical period for development of the immune system. This paper aims to describe the prevalence of allergic respiratory disorders in children below three years of age in the general population, despite the lack of shared definition of asthma and allergic rhinitis among studies.
  
  
  BACKGROUND
  Doctor-diagnosed asthma occurs in 5% of children below two years of age. One third of children below three years of age experience wheeze during a lower respiratory tract infection, but only 7% of children wheeze apart from a respiratory infection. Asthma-like cough and bronchial obstruction symptoms are reported in respectively 15% and 9% of children below two years of age. Depending on the definition of allergic rhinitis used, its prevalence varies from 1 to 30% among two years old children.
  
  
  CONCLUSIONS
  Definitions of allergic respiratory tract disorders in infants become more elaborate involving parental and personal history of allergy and medication; epidemiological research now attempts to identify, using biological evidence of atopy, infants at risk of persistent allergic disorders.
  
  
  CONCLUSIONS
  A better definition of allergic respiratory disorders in infants may help epidemiological research and early care management.
authors.affiliation: Laboratoire Santé Publique et Environnement, EA 4064-Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Herr
authors.forename: L
authors.initials: L
authors.lastname: Nikasinovic
authors.forename: B
authors.initials: B
authors.lastname: Clarisse
authors.forename: I
authors.initials: I
authors.lastname: Momas
authors.forename: J
authors.initials: J
authors.lastname: Just
mesh_terms: D015415:Biomarkers; D006801:Humans; D007223:Infant; D012130:Respiratory Hypersensitivity / Q000175:diagnosis / Q000453:epidemiology*
chemical_list: D015415:Biomarkers