title: Characteristics of patients patch tested in the European Surveillance System on Contact Allergies (ESSCA) network, 2009-2012.
abstract: BACKGROUND
  Patch test results often vary between departments, and also between countries. Such variation may be partly attributable to systematic effects introduced by patient characteristics, differing exposures, patient selection, or methodological differences.
  
  
  OBJECTIVE
  To examine the amount of variation of patient characteristics in terms of the MOAHLFA index and of the proportion of patients with at least one positive reaction to the (European) baseline series ('P' measure), and to examine potential reasons for the variation.
  
  
  METHODS
  A retrospective analysis was performed of patch test data from 63 530 consultations collected by 53 departments from 12 countries participating in the European Surveillance System on Contact Allergies (ESSCA) ( www.essca-dc.org) between 2009 and 2012.
  
  
  RESULTS
  Considerable variation in the prevalence of the MOAHLFA factors between departments was found, caused, for example, by differing specializations (e.g. occupational dermatology) or patient characteristics. Notable variation concerning the 'P' measure was observed; however, larger national networks (contributing to the ESSCA) tend to have quite similar ranges of this measure.
  
  
  CONCLUSIONS
  Data from one department per country give valuable insights into the spectrum of contact allergy prevalence rates in that country, but are not as representative as national data pooled from several departments.
authors.affiliation: Department of Medical Informatics, Biometry and Epidemiology, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany.
authors.forename: Wolfgang
authors.identifier: http://orcid.org/0000-0002-4498-3710
authors.initials: W
authors.lastname: Uter
authors.affiliation: Department of Medical Informatics, Biometry and Epidemiology, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Gefeller
authors.affiliation: Department of Dermatology, Hospital del Mar, Institut Mar d'Investigacions Mediques, Universitat Autónoma, 08003 Barcelona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Giménez-Arnau
authors.affiliation: Department of Dermatology, University of Witten/Herdecke and Klinikum Dortmund (formerly), 44137 Dortmund, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Frosch
authors.affiliation: Department of Dermato-Allergology, National Allergy Research Centre, Gentofte Hospital, University of Copenhagen, 2900 Hellerup, Denmark.
authors.forename: Jeanne
authors.initials: J
authors.lastname: Duus Johansen
authors.affiliation: Dermatology, University Medical Centre Groningen, University of Groningen, 9700 RB, Groningen, The Netherlands.
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Schuttelaar
authors.affiliation: Department of Dermatology, VU University Medical Centre, 1081 HV Amsterdam, The Netherlands.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rustemeyer
authors.affiliation: Department of Public Health, Occupational Medicine, University of Trieste, IT-34129 Trieste, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Larese Filon
authors.affiliation: Department of Dermatology, University Medical Centre Maribor, 2000 Maribor, Slovenia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Dugonik
authors.affiliation: Allergy Unit, Department of Dermatology, University Hospital, 4031 Basel, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bircher
authors.affiliation: Spire Hospital, Leeds, LS8 1NT, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Wilkinson
mesh_terms: D000328:Adult; D017677:Age Distribution; D015331:Cohort Studies; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000453:epidemiology*; D003876:Dermatitis, Atopic / Q000453:epidemiology; D009783:Dermatitis, Occupational / Q000175:diagnosis / Q000453:epidemiology*; D005060:Europe / Q000453:epidemiology; D005148:Facial Dermatoses / Q000453:epidemiology*; D005260:Female; D006229:Hand Dermatoses / Q000453:epidemiology*; D006801:Humans; D007868:Leg Dermatoses / Q000453:epidemiology*; D008297:Male; D010328:Patch Tests / Q000706:statistics & numerical data*; D018579:Patient Selection; D015995:Prevalence; D012189:Retrospective Studies; D017678:Sex Distribution
keywords: clinical epidemiology; contact allergy; patch testing