Delayed hypersensitivity or geographic tongue: A diagnostic dilemma

Delayed hypersensitivity can occur following the use of a wide range of materials used in dentistry. These adverse reactions can be either localized or diffuse, and can mimic oral lesions of other aetiology. Delayed hypersensitivity to dental amalgam commonly presents as lichenoid oral lesions. We report the case of a patient who presented to us with burning and itching sensations on the tongue three days after restoration of his lower permanent molars with silver amalgam. Within a day, the initially well circumscribed lesions of the tongue became diffuse. Atrophy of the lingual papillae gave an appearance of a geographic tongue. Following replacement of the amalgam restoration, symptoms rapidly subsided and there was a significant improvement of the lesion.