title: [On the seasonality of dermatoses: a retrospective analysis of search engine query data depending on the season].
abstract: BACKGROUND
  The volume of search engine queries about disease-relevant items reflects public interest and correlates with disease prevalence as proven by the example of flu (influenza). Other influences include media attention or holidays.
  
  
  OBJECTIVE
  The present work investigates if the seasonality of prevalence or symptom severity of dermatoses correlates with search engine query data.
  
  
  METHODS
  The relative weekly volume of dermatological relevant search terms was assessed by the online tool Google Trends for the years 2009-2013. For each item, the degree of seasonality was calculated via frequency analysis and a geometric approach.
  
  
  RESULTS
  Many dermatoses show a marked seasonality, reflected by search engine query volumes. Unexpected seasonal variations of these queries suggest a previously unknown variability of the respective disease prevalence. Furthermore, using the example of allergic rhinitis, a close correlation of search engine query data with actual pollen count can be demonstrated.
  
  
  CONCLUSIONS
  In many cases, search engine query data are appropriate to estimate seasonal variability in prevalence of common dermatoses. This finding may be useful for real-time analysis and formation of hypotheses concerning pathogenetic or symptom aggravating mechanisms and may thus contribute to improvement of diagnostics and prevention of skin diseases.
authors.affiliation: Klinik für Hautkrankheiten, Universitätsklinikum Jena, Erfurter Str. 35, 07743, Jena, Deutschland, johannes.koehler@med.uni-jena.de.
authors.forename: M J
authors.initials: MJ
authors.lastname: Köhler
authors.forename: S
authors.initials: S
authors.lastname: Springer
authors.forename: M
authors.initials: M
authors.lastname: Kaatz
mesh_terms: D057225:Data Mining / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D011159:Population Surveillance / Q000379:methods*; D057386:Search Engine / Q000706:statistics & numerical data*; D012621:Seasons; D012871:Skin Diseases / Q000453:epidemiology*; D062211:Spatio-Temporal Analysis; D013223:Statistics as Topic