Is it true or false that evaporation causes transepidermal water loss?

• A. True
• B. False
• C. Only in arid climates
• D. Only during exercise

Answer: (A)

Evaporation does indeed cause transepidermal water loss (TEWL), making the statement true. TEWL refers to the loss of water from the body through the epidermis, the outermost layer of the skin. This water loss occurs continuously as the skin is exposed to the environment. The process is primarily driven by the gradient of water vapor concentration between the inside of the skin and the external atmosphere.

As water molecules at the skin's surface evaporate, they leave the skin, which can lead to dehydration if not replenished. Environmental factors such as humidity, temperature, and air circulation can influence the rate of evaporation and TEWL. In terms of skin physiology, maintaining adequate hydration is crucial for barrier function, elasticity, and overall skin health.

Other options suggest conditions that may influence TEWL but do not address the fundamental fact that evaporation is a significant factor in transepidermal water loss regardless of the environment or activity level. Thus, the assertion that evaporation causes TEWL is accurate.