Korean J Dermatol.  2021 Jul;59(6):456-461.

Seasonal Variability in the Facial Skin Biophysical Properties: The Importance of Constant Temperature and Humidity for the Analysis of Skin Hydration in Busan, Korea

• Seol JE
• Cho GJ
• Park SH
• Park IH
• Jung SY
• Kim H

Abstract

Background
The skin barrier is made of the outermost layers of skin and is responsible for preventing cutaneous water loss. Skin barrier function is easily affected by external environmental factors, such as temperature and relative humidity, especially in areas with four distinct seasons, such as Busan, Korea.
Objective
This study was conducted to analyze the seasonal variation in skin barrier function on the face and to determine whether it is affected by thermo-hygrostat conditioning.
Methods
Ten healthy female volunteers aged 28 to 34 years were enrolled in this study. Each subject was put into a thermo-hygrostat–controlled room maintained at a temperature of 22.4°C to 23.8°C with a relative humidity of 50.2% to 52.0%. Transepidermal water loss (TEWL) and stratum corneum hydration (SCH) were measured before and after a 20-minute session in the room. Measurements were taken once in the middle of each season.
Results
Regardless of thermo-hygrostat conditioning, TEWL and SCH values changed significantly between all four seasons (both p＜0.001). With thermo-hygrostat conditioning, 1 of 6 ΔTEWL and 4 of 6 ΔSCH values showed significant seasonal differences in post-hoc analysis. Difference of TEWL and SCH obtained before and after thermo-hygrostat conditioning was significant only in summer (TEWL, p=0.009; SCH, p=0.002).
Conclusion
Skin barrier function differed significantly between seasons, regardless of thermo-hygrostat conditioning. Thermo-hygrostat conditioning significantly affected TEWL and SCH only during summer. However, with Busan’s excessively humid summer, even a short period of thermo-hygrostat conditioning could increase the precision of skin barrier function measurement.

Keyword

Humidity; Skin; Temperature