title: Positive patch-test reactions to mixed dialkyl thioureas: cross-sectional data from the North American Contact Dermatitis Group, 1994 to 2004.
abstract: BACKGROUND
  Allergic contact dermatitis from thioureas is uncommon but may result from exposure to rubber, especially neoprene.
  
  
  OBJECTIVE
  To (1) describe the population with positive patch-test reactions to mixed dialkyl thioureas (MDTU) (ie, diethylthiourea and dibutylthiourea); (2) determine clinical and occupational relevance associated with reactions to MDTU and identify the most commonly related sources and occupations; and (3) examine the frequency of co-reacting allergens in MDTU-positive patients.
  
  
  METHODS
  A retrospective analysis of cross-sectional data of 22,025 patients patch-tested by the North American Contact Dermatitis Group between 1994 and 2004.
  
  
  RESULTS
  Of 21,898 patients tested with MDTU, 225 (1.0%) had positive reactions; of these, 173 (76.9%) were currently relevant and 29 (17.1%) were occupationally relevant. Patients positive to MDTU were 2.6 times more likely to have foot involvement than patients with positive reactions to other allergens (p < .0001). Footwear was the most commonly identified source overall (20.0%) whereas gloves were the most common occupational source. Of the 173 patients with currently relevant MDTU reactions, 24.9% also reacted to another rubber allergen.
  
  
  CONCLUSIONS
  Current clinical relevance of reactions to MDTU was high; occupational relevance was less frequent. Patch tests with common rubber allergens (carbamates, thiurams, and mercaptobenzothiazole) may fail to detect many cases of thiourea-induced rubber allergic contact dermatitis.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Warshaw
authors.forename: Jeremy W
authors.initials: JW
authors.lastname: Cook
authors.forename: Donald V
authors.initials: DV
authors.lastname: Belsito
authors.forename: Vincent A
authors.initials: VA
authors.lastname: DeLeo
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Fowler
authors.forename: Howard I
authors.initials: HI
authors.lastname: Maibach
authors.forename: James G
authors.initials: JG
authors.lastname: Marks
authors.forename: C G Toby
authors.initials: CG
authors.lastname: Mathias
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Pratt
authors.forename: Robert L
authors.initials: RL
authors.lastname: Rietschel
authors.forename: Denis
authors.initials: D
authors.lastname: Sasseville
authors.forename: Frances J
authors.initials: FJ
authors.lastname: Storrs
authors.forename: James S
authors.initials: JS
authors.lastname: Taylor
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Zug
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D003020:Clothing / Q000009:adverse effects; D003430:Cross-Sectional Studies; D019992:Databases as Topic; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D009783:Dermatitis, Occupational / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009387:Neoprene / Q000009:adverse effects; D009656:North America / Q000453:epidemiology; D010328:Patch Tests / Q000379:methods; D011237:Predictive Value of Tests; D015995:Prevalence; D012189:Retrospective Studies; D012408:Rubber / Q000009:adverse effects*; D013890:Thiourea / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D000485:Allergens; C035318:diethylthiourea; C034546:1,3-dibutyl-2-thiourea; D012408:Rubber; D009387:Neoprene; D013890:Thiourea