J Am Acad Dermatol. 1986;15:571-85.

Age changes of normal skin.
Fenske NA, Lober CW.

Solar-induced cutaneous changes are more prevalent and profound in older persons and, thus, are often inappropriately attributed to the aging process, per se. Structural and functional alterations caused by intrinsic aging and independent of environmental insults are now recognized in the skin of elderly individuals.snip... There is a progressive reduction in the density of hair follicles per unit area on the face and scalp, independent of male-pattern hair loss. The hair shaft diameter is generally reduced but in some areas, especially the ears, nose, and eyebrows of men and the upper lip and chin in women, it is increased as vellus hairs convert to cosmetically compromising terminal hairs. Functional alterations noted in the skin of elderly persons include a decreased growth rate of the epidermis, hair, and nails, delayed wound healing, reduced dermal clearance of fluids and foreign materials, and compromised vascular responsiveness. snip...Clinical correlates of these intrinsic aging changes of the skin include hair loss,...snip