title: Results of double-blind placebo-controlled challenge with nickel salts in patients affected by recurrent aphthous stomatitis.
abstract: BACKGROUND
  The aetiology of recurrent aphthous stomatitis (RAS) has so far not been completely clarified. Recently, several studies reported that patients affected by cutaneous diseases (i.e. dermatitis, eczema and urticaria) with positive patch test to nickel have a positive oral nickel challenge.
  
  
  OBJECTIVE
  A retrospective data analysis of patch test and oral nickel challenge in 380 patients (204 women and 176 men) affected by RAS was performed.
  
  
  METHODS
  We examined 380 consecutive patients affected by RAS during the period 1990-1999. In 28/380 patients the appearance of their oral symptoms coincided with the fitting of orthodontic appliance, while 352/380 reported that their oral symptoms worsened after the fitting of orthodontic appliance. All patients were studied with the series (European standard series and series for dental materials) for patch tests.
  
  
  RESULTS
  Seventy out of 380 patients (18.4%) presented a contact sensitization to nickel sulphate (positive patch test). In all of these, the orthodontic appliance was replaced with one made of nickel-free materials. All patients were re-examined by the dentist 6 months after the removal of the orthodontic appliance. The symptoms had completely remitted in 28/70 patients, partially had improved in 31/70 patients and had remained unchanged in 11/70 patients. In all patients (n = 70) with a positive patch test to nickel we performed an oral double-blind placebo-controlled challenge (DBPC) test with nickel sulphate. The DBPC was positive in 32/70 patients, 21 of whom had partially improved and 11 had not, even after the replacement of the orthodontic appliance with material not containing nickel. None of the 28 patients in complete remission showed an adverse reaction to oral nickel challenge.
  
  
  CONCLUSIONS
  The results of this study demonstrate that, in some patients with a positive patch test to nickel sulphate, the perpetuation of RAS can be related to a hypersensitivity to ingested nickel salts, independently of local contact to nickel.
authors.affiliation: Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Verona, Verona, Italia. marialuisa.pacor@univr.it
authors.forename: M L
authors.initials: ML
authors.lastname: Pacor
authors.forename: G
authors.initials: G
authors.lastname: Di Lorenzo
authors.forename: N
authors.initials: N
authors.lastname: Martinelli
authors.forename: G
authors.initials: G
authors.lastname: Lombardo
authors.forename: A
authors.initials: A
authors.lastname: Di Gregoli
authors.forename: P
authors.initials: P
authors.lastname: Mansueto
authors.forename: G B
authors.initials: GB
authors.lastname: Rini
authors.forename: G
authors.initials: G
authors.lastname: Corrocher
authors.forename: R
authors.initials: R
authors.lastname: Corrocher
mesh_terms: D000328:Adult; D000368:Aged; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000276:immunology*; D009967:Orthodontic Appliances / Q000009:adverse effects; D010328:Patch Tests; D012189:Retrospective Studies; D013281:Stomatitis, Aphthous / Q000209:etiology / Q000276:immunology*
chemical_list: C029938:nickel sulfate; D009532:Nickel