title: Allergic contact dermatitis from methyldibromoglutaronitrile.
abstract: BACKGROUND
  Arriving at a diagnosis of allergic contact dermatitis is a multistep procedure including the establishing of contact allergy, demonstration of current exposure to the sensitizer, and assessment of clinical relevance. Sometimes, these steps are easy to get through; at other times, there may be problems with every step.
  
  
  OBJECTIVE
  To demonstrate the possible difficulties and pitfalls in establishing the presence of contact allergy and diagnosing allergic contact dermatitis from exposure to the preservative methyldibromoglutaronitrile (MDBGN).
  
  
  METHODS
  Simultaneous patch-testing with petrolatum preparations of MDBGN at various concentrations, use testing, and chemical analysis with high-performance liquid chromatography (HPLC).
  
  
  RESULTS
  Contact allergy to MDBGN was established in two cases, with MDBGN in petrolatum at 0.5%. Results of HPLC investigation of moisturizers used by the patients and yielding positive results on patch and use tests disagreed with the information about preservatives on the labels of the moisturizers and with the Material Safety Data Sheets (MSDSs).
  
  
  CONCLUSIONS
  Patch testing with MDBGN in petrolatum at a concentration of less than 0.5% may fail to diagnose a clinically relevant contact allergy. The information on labels of products, on MSDSs, and from manufacturers may not be reliable, which indicates the need for chemical analyses.
authors.affiliation: Department of Occupational and Environmental Dermatology, University Hospital, Malmö, Sweden. magnus.bruze@derm.mas.lu.se
authors.forename: Magnus
authors.initials: M
authors.lastname: Bruze
authors.forename: Birgitta
authors.initials: B
authors.lastname: Gruvberger
authors.forename: An
authors.initials: A
authors.lastname: Goossens
authors.forename: Monica
authors.initials: M
authors.lastname: Hindsén
authors.forename: Ann
authors.initials: A
authors.lastname: Pontén
mesh_terms: D000328:Adult; D000485:Allergens / Q000009:adverse effects / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D005188:False Negative Reactions; D005260:Female; D006229:Hand Dermatoses / Q000139:chemically induced / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009570:Nitriles / Q000009:adverse effects / Q000737:chemistry; D010328:Patch Tests; D010577:Petrolatum / Q000009:adverse effects / Q000737:chemistry; D011237:Predictive Value of Tests
chemical_list: D000485:Allergens; D009570:Nitriles; D010577:Petrolatum; C039411:1,2-dibromo-2,4-dicyanobutane