title: Concomitant patch test reactions to mercapto mix and mercaptobenzothiazole: retrospective analysis from the North American Contact Dermatitis Group, 1994-2008.
abstract: BACKGROUND
  Mercaptobenzothiazole (MBT) and mercapto compounds are primarily used in rubber products.
  
  
  OBJECTIVE
  This study aimed to examine concomitant-positive rates of MBT (1% pet) and the 4-part mercapto mix (MM) (1% pet).
  
  
  METHODS
  This is a retrospective cross-sectional data from the North American Contact Dermatitis Group.
  
  
  RESULTS
  A total of 30,880 patients were patch tested to MM and MBT. There were 333 positive reactions to MM and 427 positive reactions to MBT. Ninety-eight patients were positive to MM alone, 192 to MBT alone, and 235 reacted to both. Forty-five percent (192/427) of MBT reactions would have been missed by only testing to MM, and 29% (98/333) of MM reactions would have been missed by testing to MBT alone. Most of these "missed" reactions, however, were doubtful (+/-) or mild (+) (MBT, 65%; MM, 78%), whereas most reactions in patients who reacted to both were moderate (++) and/or strong (+++) (52.3%). Gloves were the most common source.
  
  
  CONCLUSIONS
  Mercaptobenzothiazole is the preferential screening allergen for mercapto compounds because of the following: (1) greater proportion of missed reactions with MM; (2) greater proportion of doubtful/mild reactions in the missed group for MM; and (3) in the group positive to both, the low rate (2%) of moderate/strong reactions to MM and doubtful/mild reactions to MBT as compared with the converse (21%). Mercapto mix may be useful in an auxiliary rubber series.
authors.affiliation: From the *Department of Dermatology, Veterans Affairs Medical Center, University of Minnesota, Minneapolis, MN; †Department of Dermatology, University of Cincinnati, Cincinnati, OH; ‡Division of Dermatology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; §Department of Dermatology, Columbia University, New York, NY; ∥Department of Dermatology, University of California San Francisco, San Francisco, CA; ¶Department of Dermatology, Cleveland Clinic, Cleveland, OH; #Division of Dermatology, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada; **Dartmouth-Hitchcock Medical Center, Lebanon, NH; ††Ohio State University Medical Center, Columbus, OH; ‡‡Department of Dermatology, University of Louisville, Louisville, KY; §§Department of Dermatology, Pennsylvania State University, Philadelphia, PA; ∥∥Division of Dermatology, University of Ottawa, Ottawa, Ontario, Canada; and ¶¶Department of Dermatology, Oregon Health Science University, Portland, OR.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Warshaw
authors.forename: Srihari I
authors.initials: SI
authors.lastname: Raju
authors.forename: C G Toby
authors.initials: CG
authors.lastname: Mathias
authors.forename: Joel G
authors.initials: JG
authors.lastname: DeKoven
authors.forename: Donald V
authors.initials: DV
authors.lastname: Belsito
authors.forename: Howard I
authors.initials: HI
authors.lastname: Maibach
authors.forename: James S
authors.initials: JS
authors.lastname: Taylor
authors.forename: Denis
authors.initials: D
authors.lastname: Sasseville
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Zug
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Zirwas
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Fowler
authors.forename: Vincent A
authors.initials: VA
authors.lastname: DeLeo
authors.forename: James G
authors.initials: JG
authors.lastname: Marks
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Pratt
authors.forename: Frances J
authors.initials: FJ
authors.lastname: Storrs
mesh_terms: D000485:Allergens / Q000008:administration & dosage; D052160:Benzothiazoles / Q000008:administration & dosage; D003429:Cross Reactions; D003430:Cross-Sectional Studies; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis*; D004338:Drug Combinations; D005260:Female; D006801:Humans; D020315:Latex Hypersensitivity / Q000175:diagnosis*; D008297:Male; D009656:North America; D010328:Patch Tests / Q000379:methods*; D012189:Retrospective Studies
chemical_list: D000485:Allergens; D052160:Benzothiazoles; D004338:Drug Combinations; C005563:captax; C028000:dibenzothiazyl disulfide