Reepithelialisation

Reepithelialisation, or re-epithelialisation, is the process by which an epithelial layer is restored over a damaged wound bed to reestablish the epidermal barrier. In cutaneous injuries, keratinocytes at the wound edges become activated and migrate as a cohesive sheet to cover the defect, often forming an advancing epithelial tongue that moves across the granulation tissue. Proliferation of basal keratinocytes replenishes the epidermal cell population, and a new basement membrane is laid down as differentiation proceeds.

Migration and proliferation are guided by signals from growth factors and cytokines in the wound environment. Epidermal growth factor, transforming growth factor-α, fibroblast growth factor, and vitamin-derived signals stimulate keratinocyte movement and division, while transforming growth factor-β modulates matrix remodeling and scarring. The migrating cells interact with provisional extracellular matrix components such as fibronectin and laminin; integrin receptors coordinate adhesion and movement. A reformed basement membrane separates epidermis from the underlying dermis during restoration.

Re-epithelialisation occurs during the proliferative phase of wound healing and is influenced by wound size, depth, vascularity, moisture balance, and infection. Adequate nutrition and absence of ongoing inflammation support timely closure, whereas chronic wounds and diabetic or ischemic states frequently exhibit delayed re-epithelialisation. In burns or scars, epithelial cells from hair follicles and sweat glands can contribute to coverage when the surface skin is damaged.

Clinically, successful re-epithelialisation is indicated by continuous, barrier-forming epidermis with minimal erosions. Delays increase infection risk and may lead to opacity or scar formation. The process is routinely assessed alongside other wound healing stages as part of overall wound management.