Skin Research and Technology 2015; 21: 511–512 Printed in Singapore All rights reserved doi: 10.1111/srt.12221
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Skin Research and Technology
Letter to the Editor
Characterization of coal tattoos by Raman spectroscopy E. Cinotti1, B. Labeille1, A. Boukenter2, Y. Ouerdane2, F. Cambazard1 and J. L. Perrot1 1
Department of Dermatology, University Hospital of Saint Etienne, Saint-Etienne, France and 2Laboratoire Hubert Curien, CNRS UMR-5516 F, University of St-Etienne, Saint-Etienne, France
of tattoo pigments could be useful for dermatologists in case of allergic adverse reaction or for laser tattoo removal, but it is often difficult to identify them because ink manufacturers often do not disclose ingredients in their products. Moreover, the chemical composition of tattooing pigments continuously changes over time according to available technologies and materials (1). Natural colored
Fig. 1. Clinical appearance of the cutaneous pigmentations of the two minors.
metallic compounds and salts have been progressively substituted by synthetic organic pigments that possess superior light fastness, resistance to enzymatic digestion and are available in a wider range of hues (1). Our group recently described the application of Raman micro-spectroscopy for the characterization of cutaneous foreign bodies (2, 3) and of endogenous material crystals accumulated in the skin in case of metabolic disorders (4). Poon et al. (1) demonstrated that it is possible to identify organic tattoo pigments using Raman microspectroscopy in cryo-sectioned pig skin samples. We describe two cases where Raman Spectroscopy signatures identified the pigment of the tattoos of two coal-miners. Two skin biopsies of 4 mm were taken from two dark lesions from two 77-year-old male subjects that had been presenting linear black
Fig. 2. The Raman spectrum of the cutaneous pigmentations showed two peaks at 1587 and 1364 cm arbitrary units (a.u.); x-axis: wavenumber (cm 1).
characteristic of coal. y-axis: intensity in
Letter to the Editor
pigmentations on their knees for several years (Fig. 1). Both subjects had worked in the same coal mine of Saint-Etienne, France, and their lesions were clinically evocative for incidental coal tattoos. The skin biopsies were immediately frozen at 20°C and analyzed 1 week later by the Horiba Jobin-Yvon confocal micro-spectrometer (LabRAM ARAMIS, Horiba Jobin-Yvon, Villeneuve d’Ascq, France) using a HeNe (633 nm) laser. Raman spectroscopy showed two peaks at 1587 and 1364 cm 1 (Fig. 2), characteristic of coal (5). It was therefore possible to confirm the diagnosis of coal tattoo by determining the chemical composition of the specimens. Interestingly the specimens of both patients showed exactly the same Raman peak signatures
References 1. Poon KWC, Dadour IR, McKinley AJ. In situ chemical analysis of modern organic tattooing inks and pigments by micro-Raman spectroscopy. J Raman Spectrosc 2008; 39: 1227–1237. 2. Cinotti E, Perrot JL, Labeille B et al. Identification of a soft tissue filler by ex vivo confocal microscopy and Raman spectroscopy in a case of adverse reaction to the filler. Skin Res Technol 2015; 21: 114–118. 3. Cinotti E, Labeille B, Perrot JL et al. Characterization of cutaneous for-
confirming that the pigment had the same origin corresponding to coal from the same workplace. This anecdotal case shows that Raman spectroscopy, a powerful technique that analyses materials by detecting their composition responses (6), could be used for the chemical characterization and identification of tattoo pigments. Several future applications would be possible in the dermatological practice using in vivo Raman spectroscopy (7), for example to identify the composition of tattoo pigments to adjust laser treatments.
Conflict of interest The authors declare not to have any conflicts of interest.
eign bodies by Raman spectroscopy. Skin Res Technol 2013; 19: 508–509. 4. Cinotti E, Perrot JL, Labeille B et al. Optical diagnosis of a metabolic disease: cystinosis. J Biomed Opt 2013; 18: 046013. 5. Kostova I, Tormo L, Crespo-Feo E et al. Study of coal and graphite specimens by means of Raman and cathodoluminescence. Spectrochim Acta A Mol Biomol Spectrosc 2012; 91: 67–74. 6. Schrader B. Infrared and Raman spectroscopy. New York: VCH Publishers Inc., 1995.
7. Patil CA, Arrasmith CL, Mackanos MA et al. A handheld laser scanning confocal reflectance imaging-confocal Raman microspectroscopy system. Biomed Opt Express 2012; 3: 488–502. Address: E. Cinotti H^opital Nord Saint-Etienne Saint Etienne Cedex 2 42055 France Tel: 00 33 (0)4 77 82 84 21 Fax: 00 33 (0)4 77 82 84 01 e-mail: [email protected]