title: Polysensitization and individual susceptibility to allergic contact dermatitis.
abstract: BACKGROUND
  Patients with allergic contact dermatitis to 1 antigen have been shown to be at increased risk of developing delayed type hypersensitivity reactions to additional antigens. Both environmental and genetic factors likely influence the risk of sensitization.
  
  
  OBJECTIVE
  The aim of this study was to determine whether polysensitization occurs at a higher frequency than would be expected based on chance and whether polysensitization occurs more often in subsets of patients with hand involvement and atopic dermatitis.
  
  
  METHODS
  From a database of patch test results from a single practitioner, the probability of having positive reactions to 3 or more unrelated allergens was calculated under the assumption that positive reactions are independent and compared with the observed proportion having positive reactions to 3 or more unrelated allergens. The analysis was repeated excluding patients with leg involvement as a proxy for venous insufficiency dermatitis. The proportion of patients from the polysensitized and nonpolysensitized cohorts with either hand involvement or a history of atopic dermatitis was also calculated.
  
  
  CONCLUSIONS
  Polysensitization occurs more often than expected based on chance. Polysensitized patients were more likely to have hand dermatitis. Atopic dermatitis was not significantly associated with polysensitization in this analysis. Polysensitized individuals may represent a phenotype with increased genetic susceptibility to sensitization.
authors.affiliation: From the *University Hospitals Case Medical Center; and †Case Western Reserve University, Cleveland, OH.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Gosnell
authors.forename: Brian
authors.initials: B
authors.lastname: Schmotzer
authors.forename: Susan T
authors.initials: ST
authors.lastname: Nedorost
mesh_terms: D000485:Allergens / Q000276:immunology*; D015331:Cohort Studies; D016208:Databases, Factual; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology / Q000276:immunology*; D003876:Dermatitis, Atopic / Q000453:epidemiology / Q000276:immunology; D006229:Hand Dermatoses / Q000453:epidemiology / Q000276:immunology*; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000453:epidemiology / Q000276:immunology; D010328:Patch Tests; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000485:Allergens