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

Abstract

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. 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. Pvalues 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. Our data suggest a useful model for evaluating physiologic skin changes after laser surgery in patients with nevus of Ota.