title: The allergic march comprises the coexistence of related patterns of allergic disease not just the progressive development of one disease.
abstract: OBJECTIVE
  This study explored the development and comorbidity of allergic diseases by analysing the relationship between allergic manifestations in infancy and at the age of 8.
  
  
  METHODS
  We included 5654 children born in Sweden in 2003 in a longitudinal study. Parents answered postal questionnaires when the children were six months and one, four-and-a-half and eight years of age.
  
  
  RESULTS
  The response rate at eight years was 4051 (71.6%), and we analysed 3382 children with complete data. The number of manifestations in infancy increased the risk of allergic disease at eight years of age: 72% of children with one early manifestation were symptom free at 8, compared to 45% with two or more manifestations. Similar manifestations occurred in infancy and at the age of 8, for example recurrent wheeze increased the risk of doctor-diagnosed asthma by an adjusted odds ratio of 6.5. Eczema and food allergy independently increased the risk of all four allergic manifestations at eight years.
  
  
  CONCLUSIONS
  Allergic disease at the age of 8 was related to the number of allergic manifestations in infancy. Manifestations were similar at both ages, suggesting an allergic march with the coexistence of disease patterns rather than the progressive development of one disease.
authors.affiliation: Department of Paediatrics, University of Gothenburg, Queen Silvia Children's Hospital, Gothenburg, Sweden.
authors.forename: Emma
authors.initials: E
authors.lastname: Goksör
authors.affiliation: Department of Paediatrics, University of Gothenburg, Queen Silvia Children's Hospital, Gothenburg, Sweden.
authors.forename: Petra
authors.initials: P
authors.lastname: Loid
authors.affiliation: Department of Paediatrics, University of Gothenburg, Queen Silvia Children's Hospital, Gothenburg, Sweden.
authors.forename: Bernt
authors.identifier: http://orcid.org/0000-0002-3557-2995
authors.initials: B
authors.lastname: Alm
authors.affiliation: Department of Paediatrics, University of Gothenburg, Queen Silvia Children's Hospital, Gothenburg, Sweden.
authors.forename: Nils
authors.initials: N
authors.lastname: Åberg
authors.affiliation: Department of Paediatrics, University of Gothenburg, Queen Silvia Children's Hospital, Gothenburg, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Wennergren
mesh_terms: D000367:Age Factors; D000818:Animals; D001249:Asthma / Q000453:epidemiology; D002415:Cats; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D004285:Dogs; D004485:Eczema / Q000453:epidemiology*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000453:epidemiology*; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence; D011817:Rabbits; D013548:Sweden / Q000453:epidemiology
keywords: Allergic march; Allergic rhinitis; Asthma; Eczema; Food allergy