Hyperpigmentation associated with oral minocycline

Two patients receiving minocycline developed blue-black pigmentation on the legs. Biopsies from the pigmented areas demonstrated granules containing iron, a pigment with staining properties similar to melanin, and a third pigment which may be a degradation product of minocycline. Electron microscopy showed that some, but not all the granules were membranebound and they were situated mainly within macrophages. Analytical electron microscopy showed that the granules contained iron, sulphur, chlorine and, in one case, calcium.