Dellepidermide

Dellepidermide is the Italian term for the epidermis, the outermost layer of the skin. It forms a protective barrier between the body and the external environment and participates in immune defense, sensation, and pigmentation. The epidermis lies on the dermis, separated by the basement membrane, and is avascular; its cells obtain nutrients through diffusion from the underlying connective tissue.

Anatomically, the epidermis consists of several stratified layers: basale (germinativum), spinosum, granulosum, lucidum (present only in thick skin), and corneum. The principal cell type is the keratinocyte, which originates in the basal layer and migrates outward as it differentiates, eventually forming the stratum corneum. Other cells include melanocytes (pigment-producing), Langerhans cells (dendritic immune cells), and Merkel cells (mechanoreceptors).

The epidermis lacks blood vessels; nourishment and signaling occur via the dermis. Keratinocyte turnover from basal to corneum typically takes about 28 days in healthy adults. The epidermis also contains intercellular junctions that maintain barrier integrity and contribute to transepidermal water loss control.

Clinical relevance includes conditions that alter epidermal structure or turnover, such as dermatitis, psoriasis, and hyperkeratosis; epidermal cancers include basal cell carcinoma and squamous cell carcinoma, while melanoma originates from melanocytes at the epidermal-dermal junction.