By Gary M. White, MD
Minocycline pigmentation is the development of blue spots or a bluish discoloration of the teeth, nails or sclera in a patient on longterm minocycline. As a totally separate condition minocycine may stimulate melanocytes, causing "minocycline melanosis." Minocycline is commonly given for acne and for rheumatoid arthritis.
Blue discoloration of the skin may develop on the legs, feet, face, in acne scars, in sclera [BJD 1996;135;314], and diffusely during minocycline therapy. It may occur as early as the first year of therapy. The teeth, sclera, and nails may also develop a blue-gray discoloration. The gums may appear involved but this actually results from pigmentation of the underlying bone. Pigmentation of bones, thyroid, substantia nigra, atherosclerotic plaques, and conjunctival cysts have been reported. Pefloxacin, a quinolone antibiotic, has caused similar changes on the shins.
Various theories have been proposed about the pigment including: an insoluble minocycline-melanin complex, a complex of minocycline chelated with iron or a drug metabolite-protein complex chelated with calcium.
The pigmentation of the skin usually fades over months to years if the minocycline is stopped. Various Q-switched lasers have been used, e.g., Ruby, Nd:YAG, and Alexandrite. One study found the Ruby laser to be more effective than the YAG [Arch Dermatol. 1996;132:1250–1251]. The Alexandrite 755 nm laser provided effective clearing of the minocycline hyperpigmentation requiring just 2 treatments in a patient with pigmentation of the sun-exposed areas of the face [Clin Cosmet Investig Dermatol. 2013; 6: 159–162].
With regard to pigmentation of the teeth, bleaching by the dentist and in-home bleaching systems may be used although complete clearing may not occur [J Esthetic Dentistry 1997;9;30]. In one case [Annals Pharmacology 1998;32;887], the discoloration was removed easily with dental cleaning, although this is the exception.
Minocycline can bind to blood and cause bruises to persist for years. This woman with rheumatoid arthritis on minocycline had a hematoma after surgery that never went away.
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