Mucosal pigmentation after oral lichen planus treatment with topical tacrolimus

Erosive oral lichen planus (OLP) is a painful chronic inflammatory disease that is sometimes resistant to systemic or topical therapies. Topical steroids remain the mainstay of therapy, but topical tacrolimus has recently been used to treat OLP resistant to topical corticosteroids. Topical tacrolimus appears as an effective and safe treatment of symptomatic OLP. We report the first histopathologically documented case of oral mucosa pigmentation after OLP treatment with topical tacrolimus. The relation between tacrolimus treatment and staining was suggested by the appearance of pigmentation during topical tacrolimus treatment and its clinical disappearance when treatment was stopped. Histopathology showed an increase in melanocyte numbers and melanogenesis.