Aging skin.

Environmentally induced (extrinsic) changes in aging skin are often difficult to distinguish from physiologic (intrinsic) changes due to longevity. Structural alterations include dermoepidermal junction flattening, epidermal basal cell heterogeneity, depletion of Langerhans' cells and melanocytes, dermal and subcutaneous atrophy, appendageal deterioration and a decline in special sensory end organs. In addition to cosmetically compromising changes in the skin, hair and nails, clinical manifestations include a propensity to blister formation, cutaneous injury, epidermal neoplastic transformation, infection, xerosis and thermoregulatory perturbations.