Hautbarriere

Hautbarriere, commonly referred to as the skin barrier, is the functional and structural system of the outermost skin that protects the body from transepidermal water loss and from environmental insults. The barrier resides primarily in the stratum corneum, a layer of corneocytes (dead skin cells) embedded in a lipid matrix composed mainly of ceramides, cholesterol, and free fatty acids arranged in lamellar structures. An acidic mantle helps maintain a pH around 4.5 to 5.5, supporting enzymatic activity and antimicrobial defense.

Functions of the Hautbarriere include minimizing water loss, maintaining hydration, and providing a shield against irritants, allergens, microbes, and physical damage. A healthy barrier also participates in immune signaling and helps regulate inflammatory responses.

Maintenance and repair: The barrier is dynamic and continually renewed, with turnover estimates around 28 days. Disruption increases water loss and sensitization risk. Repair relies on lipid synthesis and natural moisturizing factors within corneocytes. Emollients and moisturizers that contain ceramides, cholesterol, and fatty acids support barrier restoration and reduce transepidermal water loss. Avoiding harsh cleansing products, excessive washing, and occlusive conditions that hinder skin respiration can help preserve barrier integrity.

Clinical relevance: Barrier dysfunction is central to conditions such as atopic dermatitis, ichthyosis, and psoriasis, and may accompany contact dermatitis. Measurement of transepidermal water loss (TEWL) is used to assess barrier integrity. Management emphasizes gentle cleansing, regular moisturization, and targeted therapies that replenish lipids and support skin renewal.