title: The inhibitory effects of topical chelating agents and antioxidants on nickel-induced hypersensitivity reactions.
abstract: BACKGROUND
  Nickel sensitivity is a common problem, often causing significant morbidity from chronic eczematous dermatitis. The main treatment, topical steroids, usually is unable to suppress the dermatitis completely.
  
  
  OBJECTIVE
  Our purpose was to study the effects of "barrier" ointments containing either chelating agents (clioquinol or ethylenediaminetetraacetic acid [EDTA]) or antioxidants (ascorbic acid or alpha-tocopherol) and 1% hydrocortisone on nickel-induced hypersensitivity reactions.
  
  
  METHODS
  Nickel-sensitive subjects were challenged with nickel-containing coins coated with the desired barrier ointment and their inhibitory effects observed. Patients with bilateral hand or earring dermatitis explored the efficacy of these agents in clinical use.
  
  
  RESULTS
  Clioquinol (3%) completely abolished the allergic reaction in all 29 subjects tested. EDTA (15%), ascorbic acid (20%), and alpha-tocopherol (10%) were less effective, and 1% hydrocortisone had no significant effect. In clinical use sites treated with a commercially available preparation containing 3% clioquinol and 1% hydrocortisone showed marked clinical improvement in all 10 subjects.
  
  
  CONCLUSIONS
  Clioquinol is a potent inhibitor of nickel-induced hypersensitivity reactions and is feasible to use as a barrier ointment to block the allergenic effects of nickel in sensitive patients.
authors.affiliation: Department of Dermatology, University of Liverpool, U.K.
authors.forename: A A
authors.initials: AA
authors.lastname: Memon
authors.forename: M M
authors.initials: MM
authors.lastname: Molokhia
authors.forename: P S
authors.initials: PS
authors.lastname: Friedmann
mesh_terms: D000287:Administration, Topical; D000975:Antioxidants / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000627:therapeutic use; D002614:Chelating Agents / Q000627:therapeutic use*; D007464:Clioquinol / Q000627:therapeutic use; D017449:Dermatitis, Allergic Contact / Q000188:drug therapy* / Q000209:etiology; D003875:Drug Eruptions / Q000188:drug therapy* / Q000209:etiology; D004492:Edetic Acid / Q000627:therapeutic use; D006801:Humans; D006854:Hydrocortisone / Q000627:therapeutic use; D009532:Nickel / Q000009:adverse effects*; D010865:Pilot Projects; D014810:Vitamin E / Q000627:therapeutic use
chemical_list: D000975:Antioxidants; D002614:Chelating Agents; D014810:Vitamin E; D007464:Clioquinol; D009532:Nickel; D004492:Edetic Acid; D001205:Ascorbic Acid; D006854:Hydrocortisone