Dermatitis herpetiformis is an uncommon chronic skin disease that rarely affects the oral cavity. An unusual case of dermatitis herpetiformis, starting with oral lesions 6 months prior to the onset of skin lesions, is reported. The diagnosis was based on the typical histopathologic features and on positive direct immunofluorescence. The literature is briefly reviewed. Evaluation of laboratory findings, clinical picture, and response to sulfones is essential to the final diagnosis and is emphasized.