Changes of biophysical properties of the skin measured by non-invasive techniques after Q-switched Nd-YAG laser therapy in patients with nevus of Ota

Background/aims: The aim of the study was to objectify the effect of a Q-switched Nd-YAG laser on Ota's nevus in view of barrier function, surface contour changes, dermal blood flow, surface color changes and sebum production rate.
Methods: Fifteen Korean patients with nevus of Ota (between 14 and 54 years of age) were enrolled. All the patients were treated by Q-switched Nd-YAG laser and followed up for 12 weeks. A reflectance spectrophotometer, a colorimeter, laser Doppler flowmetry, a Tewameter, a Corneometer and a Sebumeter were used to make measurements.
Results: P values of less than 0.05 were regarded as statistically significant. In skin reflectance measurements, L * values declined for 4 weeks and increased at 12 weeks, indicating that the brightness of the lesions improved. a * values showed a significant increase at 2 and 4 weeks. On the contrary, b * values decreased at 2 weeks. Transepidermal water loss and dermal blood flux showed identical patterns, showing increases at 2 weeks. The water holding capacity decreased at 2 and 4 weeks, and thereafter showed a delayed recovery. Casual sebum production increased at 4, 8 and 12 weeks. The loss of skin roughness was observed at 4 weeks, recovering at 12 weeks, although statistically insignificant. Reflex spectrophotometry did not reflect the changing properties of the skin.
Conclusions: Our data suggest a useful model for evaluating physiologic skin changes after laser surgery in patients with nevus of Ota.