Minocycline-induced pigmentation. Incidence, prevention and management.

Pigmentation is a well recognised adverse effect of minocycline therapy. Various body sites, most notably the skin, nails, bones, thyroid, mouth and eyes are affected and the pigmentation may appear at multiple sites. In general, pigmentation results from long term administration of minocycline at cumulative doses greater than 100 g, although cutaneous or oral mucosal pigmentation may appear, regardless of dose or duration of therapy. When the skin is involved, the blue-black pigmentation develops most frequently on the shins, ankles and arms. Other patterns of skin involvement include pigmentation that is either generalised and symmetrical, or that develops at sites of inflammation. The bones of the oral cavity are probably the most frequently affected sites of pigmentation affecting greater than 20% of patients taking minocycline for more than 4 years. In contrast, the oral mucous membranes and teeth are infrequently pigmented from minocycline. Ocular, thyroid and visceral pigmentation is also relatively uncommon and usually develops only with high doses and long term minocycline use. Whereas pigmentation of the skin and oral mucosa is generally reversible when the drug is discontinued, the pigmentation is often permanent when other sites are involved. Although minocycline-induced pigmentation is not harmful, the drug should be discontinued when the adverse effect is recognised. All patients receiving minocycline, especially those treated for longer than 1 year, require screening for the development of pigmentation.