Reepithelialization

Reepithelialization, or reepithelialisation, is the process by which the epidermal barrier is restored after skin injury. It involves migration, proliferation, and differentiation of epidermal keratinocytes to cover the wound bed and re-establish the stratified epidermis. In partial-thickness wounds, reepithelialization commonly occurs from intact epidermis at the wound margins and from hair follicles and sweat glands; in full-thickness wounds, the epidermis commonly regrows from the wound edges and from dermal appendages where present.

Mechanism: Immediately after injury, basal keratinocytes at the wound margin detach and migrate as a sheet across the provisional wound bed over a provisional matrix, often involving matrix metalloproteinases to degrade damaged matrix. Growth factors such as epidermal growth factor (EGF), keratinocyte growth factor (KGF/FGF7), hepatocyte growth factor (HGF), and transforming growth factor-beta (TGF-β) stimulate proliferation and migration. Reepithelialization culminates in the reformation of the basement membrane and stratification of keratinocytes into the mature epidermis. Restored barrier function reduces transepidermal water loss and infection risk.

Factors influencing the rate of reepithelialization include wound size and depth, perfusion, oxygenation, and inflammation. Delays may result from infection, necrotic tissue, diabetes mellitus, aging, corticosteroid use, or chronic wounds. Adequate moisture, control of contamination, and stabilization of the wound environment support reepithelialization; excessive scar formation occurs in some cases when remodeling processes predominate.

Clinical relevance: In wound care, promoting timely reepithelialization is a central objective, alongside granulation tissue formation and collagen remodeling. Treatments include moist wound healing, debridement, infection control, and, in selected cases, topical growth factors or advanced therapies that stimulate keratinocyte activity.