title: The epidemiology of fragrance allergy: questions and needs.
abstract: BACKGROUND
  There are still open questions about the safety of fragrances.
  
  
  OBJECTIVE
  To evaluate the evidence concerning the frequency of contact dermatitis to fragrances in the general population and selected subgroups and the risk factors for sensitization and clinical manifestations.
  
  
  METHODS
  Review of published data.
  
  
  RESULTS
  No criteria for a reliable diagnosis of 'contact dermatitis' are available. International recommendations and standardization for patch test methods exist; however, the question whether agents that are positive are causally linked to contact dermatitis remain fraught with uncertainties concerning false-positive rates and clinical relevance. Most of the discussion concerning prevalence or incidence variations of allergic contact dermatitis to fragrances concentrate on the frequency of positive patch tests in clinical series, i.e. 'floating numerators'.
  
  
  CONCLUSIONS
  Risk assessment requires that data from different sources are integrated and compared. Both a 'sentinel surveillance' system and more refined epidemiological studies in well-defined populations are needed to reliably assess the risks associated with fragrance exposure.
authors.affiliation: Department of Dermatology, Hôpitaux Universitaires de Genève (visiting appointment), Switzerland. luigi.naldi@hcuge.ch
authors.forename: Luigi
authors.initials: L
authors.lastname: Naldi
mesh_terms: D000485:Allergens; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D010328:Patch Tests; D010476:Perfume / Q000009:adverse effects*; D012307:Risk Factors
chemical_list: D000485:Allergens; D010476:Perfume