title: Positive patch-test reactions to propylene glycol: a retrospective cross-sectional analysis from the North American Contact Dermatitis Group, 1996 to 2006.
abstract: BACKGROUND
  Propylene glycol (PG) may cause allergic or irritant contact dermatitis. It primarily functions as a vehicle, solvent, or emulsifier in cosmetics and topical medications.
  
  
  OBJECTIVE
  To characterize the prevalence of positive patch-test reactions to PG and the epidemiology of affected patients.
  
  
  METHODS
  Retrospective analysis of cross-sectional data compiled by the North American Contact Dermatitis Group (NACDG) from 1996 to 2006.
  
  
  RESULTS
  Of 23,359 patients, 810 (3.5%) had allergic patch-test reactions to 30% PG; 12.8% of the reactions were of definite clinical relevance (positive reaction to a personal product containing PG), 88.3% were considered to be currently relevant (definite, probable, or possible relevance), and 4.2% of reactions were occupation related, most commonly to mechanical and motor vehicle occupations. Common sources of PG were personal care products (creams, lotions, and cosmetics, 53.8%), topical corticosteroids (18.3%), and other topical medicaments (10.1%). In patients positive only to PG (n = 135), the face was most commonly affected (25.9%), followed by a scattered or generalized pattern (23.7%). The most common concomitant reactions included reactions to Myroxilon pereirae, fragrance mix, formaldehyde, bacitracin, methyldibromoglutaronitrile/phenoxyethanol, carba mix, and tixocortol pivalate.
  
  
  CONCLUSIONS
  In this select population of patients referred for patch testing, allergic reactions to PG were often currently clinically relevant but were rarely related to occupation. The most common sources were personal care products and topical corticosteroids.
authors.affiliation: North American Contact Dermatitis Group.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Warshaw
authors.forename: Nina C
authors.initials: NC
authors.lastname: Botto
authors.forename: Howard I
authors.initials: HI
authors.lastname: Maibach
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Fowler
authors.forename: Robert L
authors.initials: RL
authors.lastname: Rietschel
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Zug
authors.forename: Donald V
authors.initials: DV
authors.lastname: Belsito
authors.forename: James S
authors.initials: JS
authors.lastname: Taylor
authors.forename: Vincent A
authors.initials: VA
authors.lastname: DeLeo
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Pratt
authors.forename: Denis
authors.initials: D
authors.lastname: Sasseville
authors.forename: Frances J
authors.initials: FJ
authors.lastname: Storrs
authors.forename: James G
authors.initials: JG
authors.lastname: Marks
authors.forename: C G Toby
authors.initials: CG
authors.lastname: Mathias