Minocycline-induced pigmentation at sites of cutaneous inflammation.

In four cases of minocycline hydrochloride-induced cutaneous pigmentation, blue-gray discoloration in sites of cutaneous inflammation was seen in all cases. An additional finding of generalized, brown hyperpigmentation with accentuation in sun-exposed areas was noted in one. Although all of the patients had used relatively high doses of medication, the variable duration of therapy before pigmentary changes and dearth of similar reports suggest an idiosyncratic response to this commonly used medication. Histochemical stains and electron microscopic studies suggest hemosiderin or a pigment with similar staining properties; a minocycline degradation product, however, cannot be discounted.