Patch testing in oral lichenoid lesions of uncertain etiology.

BACKGROUND: The benefit of patch testing patients with oral lichenoid lesions (OLL) is still debated. OBJECTIVE: We assessed the results of patch testing in patients with multiple amalgams and multiple OLL, where the etiology of the oral mucosal disease was unclear. METHODS: Patients referred from an oral medicine clinic were patch tested to the British Society of Cutaneous Allergy standard series, dental and materials series, and, in 1 patient, the dental methacrylate series also. Patients' responses to amalgam removal were assessed during a mean follow-up of 2.6 (range, 0-4.75) years. RESULTS: Thirty-one patients with OLL were referred for patch testing. Ten (32%) patients tested positively to mercury. Eight patients with positive reactions to mercury had amalgam removal, with complete or partial resolution of the OLL in all cases (100%). CONCLUSIONS: Patients with OLL of unclear etiology adjacent to large amalgam restorations should be investigated for delayed contact hypersensitivity. Removal of amalgams in patients with positive patch test reactions to mercury results in improvement or resolution of the OLL in most patients.