Minocycline-induced cutaneous hyperpigmentation: confocal laser scanning microscope analysis.
BACKGROUND: Minocycline has a characteristic yellow-green fluorescent emission. This fluorescence has been previously demonstrated only in type 1 minocycline-induced skin hyperpigmentation. OBJECTIVE: To investigate whether the fluorescence can be detected in other types of minocycline-induced cutaneous hyperpigmentation, and to study the possible mechanisms. METHODS: Biopsies of pigmented and nonpigmented skin from 3 patients with different types of skin hyperpigmentation induced by minocycline were analysed by light microscopy and Confocal Laser Scanning Microscope (CLSM). RESULTS: A yellow-green fluorescence was observed in the hyperpigmented skin of two patients with type 2, and one patient with type 4 minocycline-induced cutaneous hyperpigmentation. No fluorescence was detected in the non-pigmented skin. CONCLUSION: Minocycline can possibly serve as a fluorescent probe in the diagnosis of all types of minocycline-induced cutaneous hyperpigmentation.