title: Contact allergy to o-cresol--a sensitizer in phenol-formaldehyde resin.
abstract: BACKGROUND
  In patients hypersensitive to phenol formaldehyde resin (PFR) it is, for therapeutic and preventive reasons, important to know the identity of the primary sensitizing substances, their sensitizing capacity, as well as their cross-reaction patterns. When elucidating the issue of cross reactivity in patients with contact allergy to simple methylol phenols (MP), o-cresol was shown to be a contact sensitizer. Besides cross reactivity, contamination of one or more MP(s) in o-cresol as well as o-cresol being a sensitizer of its own in PFR were possible explanations of the simultaneous positive patch test reactions to MP and o-cresol.
  
  
  OBJECTIVE
  The aim of this study was to investigate if the simultaneous allergic reactions to PFR and o-cresol could be explained by the presence of this substance in PFR.
  
  
  METHODS
  Patch testing, high-pressure liquid chromatography (HPLC), nuclear magnetic resonance spectrometry (NMR), gas chromatography (GC), and mass spectrometry (MS) were used.
  
  
  RESULTS
  o-Cresol was isolated from the specific PFR used in our standard patch test series and identified. The concentration in the resin was 0.066% wt/wt.
  
  
  CONCLUSIONS
  The current study establishes o-cresol as a contact sensitizer in a PFR. The observed reactions to o-cresol could be on the basis of cross reactivity or primary sensitization.
authors.affiliation: Department of Occupational and Environmental Dermatology, Malmö University Hospital, Malmö, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Bruze
authors.forename: Erik
authors.initials: E
authors.lastname: Zimerson
mesh_terms: D000485:Allergens / Q000009:adverse effects* / Q000494:pharmacology; D002849:Chromatography, Gas / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003408:Cresols / Q000009:adverse effects / Q000494:pharmacology*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D005557:Formaldehyde / Q000009:adverse effects / Q000494:pharmacology*; D006801:Humans; D007114:Immunization; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D010328:Patch Tests; D010636:Phenols / Q000009:adverse effects / Q000494:pharmacology*; D011108:Polymers / Q000009:adverse effects / Q000494:pharmacology*; D012494:Sampling Studies; D012680:Sensitivity and Specificity
chemical_list: D000485:Allergens; D003408:Cresols; D010636:Phenols; D011108:Polymers; D005557:Formaldehyde; C011529:phenol-formaldehyde resin; C034047:2-cresol