A new type of minocycline-induced cutaneous hyperpigmentation
Date
2004
Authors
Mouton R.W.
Jordaan H.F.
Schneider J.W.
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Abstract
Pigmentary disorders are recognized adverse effects of the semi-synthetic tetracycline derivative antibiotic, minocycline. Three distinct types of minocycline-induced cutaneous pigmentation have been described. Type I, blue-black pigmentation confined to sites of scarring or inflammation on the face: Type II, blue-grey circumscribed pigmentation of normal skin of the lower legs and forearms; and Type III, diffuse muddy brown pigmentation of normal skin accentuated in sun-exposed areas. We report two patients with acne vulgaris with a fourth type of minocycline-induced cutaneous pigmentation. They presented with circumscribed blue-grey pigmentation within acne scars confined to the back. Histology showed pigment within dendritic cells, and extracellularly throughout the dermis. Histochemistry identified a calcium containing melanin-like substance. Iron was absent. Immunohistochemistry confirmed some pigment-containing cells to be macrophages. Electron microscopy demonstrated electron-dense granules, free and membrane-bound, within macrophages and fibroblast-like cells. Energy-dispersive X-ray analysis confirmed the presence of calcium. Iron was absent. This fourth type of cutaneous minocycline hyperpigmentation may be a variant of Type I, but based on clinical, pathological and microanalytical differences, appears to be a new entity. The pigment may be a drug metabolite-protein complex chelated with calcium, or an insoluble minocycline-melanin complex. We propose a classification of cutaneous minocycline pigmentation based on clinico-pathological criteria.
Description
Keywords
calcium, drug metabolite, iron, melanin, minocycline, acne vulgaris, adult, article, case report, cell membrane, chelation, clinical feature, dendritic cell, dermis, disease classification, drug induced disease, electron, electron microscopy, energy, fibroblast, follow up, histochemistry, human, hyperpigmentation, immunohistochemistry, macrophage, male, mouth mucosa, patient, priority journal, scar formation, skin biopsy, skin pigmentation, solubility, X ray analysis, Acne Vulgaris, Adult, Anti-Bacterial Agents, Biopsy, Humans, Hyperpigmentation, Male, Minocycline, Skin
Citation
Clinical and Experimental Dermatology
29
1
29
1