A 61-year-old woman presented with a 2-year history of an abnormal erythematous swelling on the upper lip and cheek. Upon examination there were no other physical findings. Histological examination found discreet sarcoidal granulomas in the lower dermis. Routine laboratory studies, chest radiographs and pulmonary functions were all normal. Clinical presentation and histological findings were, therefore, compatible with the diagnosis of orofacial granulomatosis (OFG). The patient was patch tested with an extended standard series that included metal–salt, dental prosthesis, bakery and corticosteroids series.

The patch test was positive (score ++) after 48 and 72 h for mercury in the metal–salt and dental prosthesis series. During the past decade the patient had received amalgam fillings of several dental cavities, including one adjacent to the swollen cheek. The unilateral localization of the soft tissue swelling adjacent to the amalgam tooth fillings, along with the positive patch test for mercury, raised the possibility that the OFG was part of a delayed hypersensitive reaction to the fillings. The patient therefore underwent a total amalgam replacement procedure; complete disappearance of the swelling overlying the right cheek was observed within 7 weeks and the swelling of the upper lip subsided completely within 6 months. We propose that mercury in amalgam tooth fillings is another cause of OFG and suggest appropriate patch testing in patients who do not have an apparent cause of OFG.