Dental metal allergy in patients with oral, cutaneous, and genital lichenoid reactions.

BACKGROUND The subject of lichen planus (LP) and dental metal allergy long has been debated. An overwhelming majority of the existing literature focuses on mercury and gold salts in relation to oral lichen planus. OBJECTIVE Our objective was to expand current knowledge regarding LP and lichenoid lesions (LL) and dental metal allergy by investigating more metals and investigating cutaneous and genital disease in addition to oral disease. METHODS Fifty-one patients with known LP or LL were patch tested to a series of dental metals. Patients chose to replace their dental metals or make no revision. A telephone survey was conducted after 1 year to determine disease state. RESULTS Thirty-eight of 51 patients (74.5%) had at least 1 positive reaction. Twenty-five of 51 patients (49.0%) showed sensitivity to at least 1 mercurial allergen. Prevalence data for patients patch tested by the North American Contact Dermatitis Group (NACDG) from 1996 to 1998 was available for chromate, cobalt, gold, nickel, and thimerosal. The prevalence of positive reactions was higher in our group than in the NACDG group for all 5 of these allergens, and statistical significance was achieved for chromate (P = .028), gold (P = .041), and thimerosal (P = .005). Of patients who had a positive patch test reaction to 1 or more metals, 100% (9 of 9) reported improvement after metal replacement, whereas 62.5% (15 of 24) reported improvement without metal replacement. CONCLUSION Sensitization to dental metals is more common among LP and LL patients than in routinely tested patients, and might be an etiologic or triggering factor in the disease.