title: The role of patch testing in the management of oral lichenoid reactions.
abstract: OBJECTIVE
  The distinction of oral lichenoid reactions from oral lichen planus may be difficult in a clinical setting. Our aims were to ascertain the utility of patch testing to confirm the association of oral lichenoid reactions with dental restorations and to identify the benefits of replacement of restorations, primarily made of amalgam.
  
  
  METHODS
  Patients seen in an oral medicine unit over a 10-year period diagnosed with oral lichenoid reactions, with oral lichen planus resistant to treatment or with atypical lichenoid features were included in this study. All had been subjected to skin patch testing. Histopathology reports blinded to patch test results were scrutinized. Patch-test-positive subjects were advised to have their restorations replaced. All were followed up to determine disease resolution for at least 3 months thereafter.
  
  
  RESULTS
  Among 115 patients, 67.8% patients reacted positive to a dental material and nearly a quarter to mercury or amalgam. No correlation was found between pathology and skin patch testing results (P = 0.44). A total of 87 patients were followed up in clinic, and among 26 patch-test-positive patients who had their amalgam fillings replaced, moderate to complete resolution was noted in 81%.
  
  
  CONCLUSIONS
  Skin patch testing is a valuable tool to confirm clinically suspected oral lichenoid reactions. Pathology diagnoses of oral lichenoid reactions did not correlate with patch test results. Prospective studies are needed to ascertain that a clinically suspected oral lichenoid reaction with a positive patch test result may resolve after the replacement of amalgam fillings.
authors.affiliation: Department of Oral Medicine, King's College London Dental Institute, WHO Collaborating Centre for Oral Cancer, London, UK.|Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Valerie G A
authors.initials: VG
authors.lastname: Suter
authors.affiliation: Department of Oral Medicine, King's College London Dental Institute, WHO Collaborating Centre for Oral Cancer, London, UK.
authors.forename: Saman
authors.initials: S
authors.lastname: Warnakulasuriya
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D003722:Dental Alloys / Q000009:adverse effects*; D003723:Dental Amalgam / Q000009:adverse effects; D003793:Dental Restoration, Permanent / Q000009:adverse effects; D005260:Female; D006801:Humans; D017676:Lichen Planus, Oral / Q000139:chemically induced* / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008628:Mercury / Q000009:adverse effects; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology; D010328:Patch Tests / Q000379:methods*; D011446:Prospective Studies; D012189:Retrospective Studies
chemical_list: D003722:Dental Alloys; D003723:Dental Amalgam; D008628:Mercury
keywords: amalgam; dental restorative materials; mercury; oral lichen planus; oral lichenoid reactions; patch test