[Cutaneous pigmentation induced by minocycline: 2 cases].

Two new cases of cutaneous pigmentation induced by minocycline are reported, in addition to the 38 cases collected in the literature. Our first case was a 50-year old man with a history of multiple orthopaedic operations for injuries sustained in road accidents. Arthritis of the elbow, probably of bacterial origin, was treated with cephalexin and gentamicin, followed by minocycline 300 mg/day. After a total dose of 60 g of minocycline had been reached, a bluish-grey pigmentation was observed on the internal aspect of the left tibia and on the scars left by the orthopaedic operations. Subsequently, lenticular lesions of the hands developed, together with a blue area on the palate. Our second case was an 18-year old girl who presented initially with nodulo-cystic acne. Minocycline 200 mg/day was prescribed, then withdrawn on account of dizziness; no pigmentation was observed. The acne was cured after 7 months of treatment with 13-cis-retinoic acid in doses of 30 mg/day (for a patient's weight of 50 kg). A second course of minocycline 100 mg/day was prescribed; after a total dose of 3 g all the acne scars had become pigmented. A pathological study performed in the first case confirmed the data found in the literature: light microscopy displayed hyperpigmentation of the basal layer of the epidermis with Masson's silver stain, and an intrahistiocytic pigment coloured by Turnbull's stain; electron microscopy showed an increase in melanosomes within the basal keratinocytes, and a pathological accumulation of pigment in the dermis in the form of electron-dense granules usually surrounded by a membrane.(ABSTRACT TRUNCATED AT 250 WORDS)