title: Patch-test reactions to topical anesthetics: retrospective analysis of cross-sectional data, 2001 to 2004.
abstract: BACKGROUND
  Allergy to topical anesthetics is not uncommon. The cross-reactivity among topical anesthetics and the screening value of benzocaine alone are not well understood.
  
  
  OBJECTIVE
  The goals for this study were: (1) to evaluate the frequency and pattern of allergic patch-test reactions to topical anesthetics, using North American Contact Dermatitis Group (NACDG) data, and (2) to compare these results to allergen frequencies from other published studies.
  
  
  METHODS
  The NACDG patch-tested 10,061 patients between 2001 and 2004. In this analysis patients were included who had positive patch-test reactions to one or more of the following: benzocaine, lidocaine, dibucaine, tetracaine, and prilocaine.
  
  
  RESULTS
  Of patch-tested patients, 344 (3.4%) had an allergic reaction to at least one anesthetic. Of those, 320 (93.0%) had an allergic reaction to only one topical anesthetic. Overall, reactions to benzocaine (50.0%, 172 of 344) were most prevalent, followed by reactions to dibucaine (27.9%, 96 of 344); however, reactions to dibucaine were significantly more frequent in Canada than in the United States (relative risk [RR], 2.31; 95% confidence interval [CI], 1.67-3.20; p < .0001). Of patients reacting to more than one anesthetic, most (79%, 19 of 24) reacted to both an amide and an ester.
  
  
  CONCLUSIONS
  Of the topical anesthetics tested, benzocaine was the most frequent allergen overall. Over 50% of allergic reactions to topical anesthetics in this study would have been missed had benzocaine been used as a single screening agent. Cross-reactivity patterns were not consistent with structural groups.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Warshaw
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Schram
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: D000287:Administration, Topical; D000779:Anesthetics, Local / Q000009:adverse effects*; D001566:Benzocaine / Q000009:adverse effects; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D003992:Dibucaine / Q000009:adverse effects; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D010328:Patch Tests; D011237:Predictive Value of Tests; D011318:Prilocaine / Q000009:adverse effects; D012189:Retrospective Studies; D012307:Risk Factors; D013748:Tetracaine / Q000009:adverse effects; D014481:United States / Q000453:epidemiology
chemical_list: D000779:Anesthetics, Local; D011318:Prilocaine; D013748:Tetracaine; D008012:Lidocaine; D003992:Dibucaine; D001566:Benzocaine