The basic skin structure most commonly affected by
acne is the pilosebaceous unit, comprising the
sebaceous gland, vellus hair, and pore (duct).
The function of the sebaceous gland is to produce
sebum, an oily or lipid-based substance. It was once
thought that sebum had no particular function;
however, recent research has shown that sebum
transports the antioxidant vitamin E to the skin’s
surface. The pore is the opening that carries sebum to
the epidermal surface and is lined with epidermal cells.
The number of pilosebaceous units that appear on the
face, upper neck, and chest is 9 times the number
found elsewhere on the body. The pilosebaceous unit is
under stimulation at birth from maternal hormones,
atrophies (becomes smaller and less active) during
childhood, and then re-emerges during adolescence,
again due to hormonal stimulation. Hormonal
stimulation can occur also during menopause