[Background] Pachydermoperiostosis (PDP), also known as Touraine-Solente-Gole syndrome, is a genetic disease affecting the skin and bones. PDP is characterized by three main features: pachydermia, periostosis, and digital clubbing. The severity of pachydermia is currently scored by the depth of furrows on the forehead. However, this scoring system is subjective and may not be applicable to some patients who had received plastic surgery to reduce the depth of the furrows. 
[Objective] To assess pachydermia with non-invasive objective measures. 
[Result] We applied vital confocal microscopy, Vivascope®, onto the facial skin of healthy individuals and patients with PDP. We could confirm the hypertrophy of hair follicles and epidermal component in comparison with those of healthy individuals. These changes in PDP patients were observed in those who showed only a slight furrow on the forehead. There were no adverse effects by the application of Vivascope®. 
[Conclusion] Optical imaging of the skin with vital confocal microscopy would be useful to objectively evaluate the severity of pachydermia.

Non-invasive evaluation of pachydermia of pachydermoperiostosis by vital confocal microscopy