Acne Cause and Pathophysiology
Pathophysiology of Acne Introduction
The cause of acne is not completely understood.
Acne is a disease of the pilosebaceous unit or sebaceous follicles.
These specialized follicles are found in greatest numbers on the face,
chest, upper back, and upper arms.
There are four events that contribute to the development of acne. These
are follicular duct hyperkeratinization, increased sebum production, P.
acnes colonization and proliferation, and inflammation.
Acne develops when a mixture of sebum and desquamated cells obstructs
sebaceous follicles. Excessive amounts of sebum combine with excessive
numbers of desquamated epithelial cells. This material accumulates and
distends the follicle forming a microcomedo. The microcomedo expands in
size to form an open or closed comedo. P. acnes colonize and
proliferate in this mixture and releases inflammatory cytokines and
chemotactic factors. Inflammation weakens the follicular wall. The wall
ruptures, the keratin-sebum mixture leaks into the dermis and an
intense foreign body like reaction begins and leads to the development
of inflammatory lesions (papules, pustules, nodules, cysts).