Acne is caused by a combination of sebum production, irritation and blockage of the pilosebaceous follicles and the presence of Propionibacterium acnes (P. acnes) bacteria. The degree to which the skin care professional can control the multiple factors of acne determines their success in treating acne.
Sebum Production: At puberty, males and females produce testosterone, which targets the skin and sebaceous glands. 5alpha-reductase (5a-reductase) is an enzyme present in skin. It targets testosterone, converting it into dihydrotestosterone. Dihydrotestosterone directly stimulates the sebaceous glands to produce volumes of sebum.
Follicular Blockage: Sebum creates physical blocks and pockets within the follicles that act like incubation chambers for P. acnes to develop into acne infections. Additionally, multiple forms of bacteria within the follicles produce lipases (bacterial enzymes). These lipases convert the sebum within the follicles into free fatty acids. The free fatty acids inflame the cells of the follicle lining, causing hyper keratinization and rapid cellular exfoliation that congests and blocks the follicles. Inflammatory agents such as interleukin 1 and 6, interferon-gamma, tumor necrosis factor-alpha and histamine are very much involved in this inflammatory and hyper-exfoliation process. P. acnes bacteria become trapped within the follicles, multiply rapidly, and develop into acne infections.
Bacteria: Propionibacterium acnes (P. acnes) are the specific bacteria that cause acne infections. P. acnes are a natural irritant to skin, promoting additional inflammation and hyper keratinization.