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).