Seasonal variability in the biophysical properties of forehead skin in women in Guangzhou City, China

Skin appearance is influenced by biophysical parameters. Seasonal changes affect the condition of normal skin and may trigger cutaneous disorders.This study was undertaken to measure the effects of seasonal changes on biophysical parameters in the skin of female subjects living in Guangzhou City in southern China.A cross-sectional study was conducted in 178 healthy, adult Chinese women in whom forehead skin was examined in all four seasons between March 2007 and February 2008. Commercially available, non-invasive devices were used to measure skin hydration, sebum content, pH, and transepidermal water loss (TEWL) in a closed environment under controlled and constant conditions of temperature and humidity. Correlations between skin parameters and climate conditions were investigated.There were significant seasonal changes in TEWL and pH (autumn and winter > spring and summer), skin hydration (spring and summer > autumn and winter), and sebum content (spring and summer > autumn and winter). Skin hydration was correlated with average temperature and humidity. Skin TEWL and skin pH were correlated with average temperature, humidity, and ultraviolet (UV) radiation levels. Skin sebum content was correlated with average humidity.Facial skin physiology showed seasonal variations in China. The reasons for the changes may refer to seasonal changes in temperature, humidity, and UV radiation.