Transepidermal Water Loss and Sensitive Skin

Transepidermal water loss (TEWL) refers to the amount of water that naturally escapes from the skin into the surrounding environment. Even healthy skin experiences some degree of water loss, but when the skin barrier is compromised, this loss increases significantly. This can lead to dryness, tightness, and irritation—common symptoms of sensitive skin. TEWL is a key signal to the body that the skin barrier has been damaged, prompting repair mechanisms such as ceramide production. Interestingly, substances like petrolatum allow a small amount of water to escape—enough to trigger repair—while fully occlusive coverings like plastic wrap prevent healing due to complete suppression of this signal.

TEWL is important in the context of both moisturizing and cleansing. Harsh cleansers or environmental factors such as low humidity can increase water loss and worsen barrier dysfunction. Effective skin care focuses on supporting the barrier to retain moisture, especially in individuals prone to dryness or sensitivity. There’s a difference between clinically sensitive skin, where visible signs of barrier damage exist (as seen in conditions like eczema or rosacea), and self-perceived sensitive skin, where symptoms such as stinging or burning are present without visible inflammation. Both require careful evaluation and may benefit from different management strategies.

For patients who self-report sensitive skin, it’s important to rule out underlying conditions through thorough history and physical examination. These individuals might react to environmental changes or products, even if their skin appears healthy. In contrast, clinically sensitive skin often shows signs like redness, scaling, or dryness and may require pharmaceutical treatment. TEWL serves as a central concept in understanding both types of sensitivity, and educating patients about it can empower them to adopt skin care habits that maintain hydration and reduce irritation.