title: Methyldibromoglutaronitrile in leave-on products elicits contact allergy at low concentration.
abstract: BACKGROUND
  The rapidly increasing level of contact allergy to methyldibromoglutaronitrile (MDBGN) in Europe is of concern. In April 2003, the EU Commission prohibited the use of MDBGN in leave-on cosmetic products, such as creams and lotions, until a level of safe use can be defined. Industry risk assessment has indicated that such a safe level could be 50-100 p.p.m.
  
  
  OBJECTIVE
  To determine whether 50 p.p.m. or 100 p.p.m. could be tolerated by MDBGN-sensitized individuals, and to evaluate if the risk for elicitation of MDBGN allergy is higher for a leave-on product with a high lipid content than for a product with a low lipid content.
  
  
  METHODS
  Eighteen volunteers with contact allergy to MDBGN and 10 healthy controls were exposed to repeated open application tests (ROATs) with two moisturizers with a high and a low lipid content, respectively, both containing MDBGN at a concentration of 50 p.p.m. The ROATs were performed on the left and the right side of the neck for 14 days, or until a positive reaction was seen. If a positive reaction did not develop within the first 14 days, two analogous moisturizers containing 100 p.p.m. MDBGN were applied for a further 14 days. Clinical assessments were done on days 2, 3, 7, 14, 21 and 28 or when a reaction developed.
  
  
  RESULTS
  Eleven of 18 (61%) subjects developed dermatitis on the test area, of whom 10 developed a positive reaction to the 50 p.p.m. moisturizer, seven having a positive reaction on day 2 or 3. Reactions to the low-lipid moisturizer were the more frequent. All participants used more of the low-lipid moisturizer than the high-lipid moisturizer. The controls all had negative ROATs.
  
  
  CONCLUSIONS
  Even 50 p.p.m. cannot be regarded as a safe concentration for use and the prohibition of MDBGN is scientifically well founded.
authors.affiliation: National Allergy Research Centre for Consumer Products and Department of Dermatology, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark. linpe@gentoftehosp.kbhamt.dk
authors.forename: L
authors.initials: L
authors.lastname: Kynemund Pedersen
authors.forename: T
authors.initials: T
authors.lastname: Agner
authors.forename: E
authors.initials: E
authors.lastname: Held
authors.forename: J D
authors.initials: JD
authors.lastname: Johansen
mesh_terms: D000328:Adult; D000368:Aged; D003358:Cosmetics / Q000633:toxicity; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D004643:Emollients / Q000633:toxicity; D005260:Female; D006801:Humans; D008055:Lipids / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009570:Nitriles / Q000633:toxicity*; D010328:Patch Tests / Q000379:methods; D011310:Preservatives, Pharmaceutical / Q000633:toxicity; D018570:Risk Assessment / Q000379:methods
chemical_list: D003358:Cosmetics; D004643:Emollients; D008055:Lipids; D009570:Nitriles; D011310:Preservatives, Pharmaceutical; C039411:1,2-dibromo-2,4-dicyanobutane