Blue Skin, Nail, and Scleral Pigmentation Associated with Minocycline.

Minocycline, a semisynthetic derivative of tetracycline that is used to treat various infectious and noninfectious conditions, can cause tissue hyperpigmentation. The skin, oral mucosa, sclera, and rarely the nails, can all be affected. The discoloration varies from blue, slate-gray, or brown, and it typically occurs in a dose-dependent fashion. The mechanism of hyperpigmentation, however, remains largely unknown. Herein, we present a case of gray-blue hyperpigmentation of the skin, sclera, and nails after long-term treatment with minocycline for acne.