quality:corruption, structural:expansion, structural:reformatting
Other characteristics

Visible variable features of the face other than shapes and proportions include color (paleness, sun tan and genetic default pigmentation), hair (length, color, loss, graying), wrinkles, facial hair (e.g. beards), skin sagging, discolorations (dark spots, freckles and eye circles), pore -variabilities, skin blemishes (pimples, scars, burn marks). Many of these features can also vary over time due to aging, skin care, nutrition, the exposome (such as harmful substances of the general environment, workplace and cosmetics), psychological factors, and behavior (such as smoking, sleep, physical activity and sun damage).

Mechanisms underlying these include changes related to peptides (notably collagen), inflammation, production of various proteins (notably elastin and other ECM proteins), the structure of subcutaneous tissue, hormones, fibers (such as elastic fibers or elasticity) and the skin barrier.

The desire of many to look young for their age and/or attractive has led to the establishment of a large cosmetics industry, which is largely concerned with make-up that is applied on top of the skin (topically) to temporarily change appearance but it or dermatology also develop anti-aging products (and related products and procedures) that in some cases affect underlying biology and are partly applied preventively. Facial traits are also used in biometrics and there have been attempts at reproducible quantifications. Skin health is considered a major factor in human well-being and the perception of health in humans.