Oral mucosal pigmentation secondary to minocycline therapy: report of two cases and a review of the literature.

Minocycline is a semisynthetic broad-spectrum antimicrobial agent that was first introduced into clinical practice in 1967. The most common use of minocycline is for the long-term treatment of acne vulgaris. A well-recognized side effect of minocycline treatment is pigmentation, which has been reported in multiple tissues and fluids including thyroid, skin, nail beds, sclera, bone, and teeth. While there have been several reports of oral pigmentation following minocycline therapy, these have been, for the most part, pigmentation of the underlying bone with the overlying oral mucosa only appearing pigmented. We report two cases of actual pigmented oral mucosal lesions on the hard palate secondary to minocycline therapy with the accompanying histopathology, followed by a discussion of minocycline-induced oral pigmentation and a differential diagnosis of these lesions.