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One of the most worrisome and prevalent skin care problems many people suffer through at some point in their lives is some degree of acne—whether it's blackheads, whiteheads, papules, pustules or blemishes. According to the American Academy of Dermatology, approximately 85% of all people have acne at some point in their lives. This common disorder can range from mild to severe, can sometimes cause extensive scarring and usually occurs between the ages of 12–50.
Acne is not contagious; it is caused by many different factors. Several of those factors have to exist in order for the lesions to occur. Propionibacterium acnes (P. acnes) is a bacteria that is found in every human, located inside sebaceous follicles. Those who suffer from acne have a higher amount of the bacteria than an average person. P. acnes is considered to be anaerobic, meaning that it cannot survive in the presence of oxygen. In a normal skin type, there may be P. acnes bacteria present in the follicle, but the amount remains low, because the presence of oxygen in the follicle helps to continually kill bacteria. That is one reason why exfoliation is so important for all skin types, especially for clients who are prone to breakouts—sloughing off dead skin cells will allow oxygen to reach P. acnes bacteria.
Inflammation is another factor in the development of acne. It causes a chain reaction of redness, swelling and irritation, and eventually will cause the follicle walls to become damaged. The pressure of debris—including dead cells, sebum and other biochemical factors—in the follicle will cause the walls to rupture. The debris, including the P. acnes bacteria, will move into the dermis. White blood cells arrive at the site of the rupture and release enzymes to dissolve the debris in the lesion. These enzymes affect the follicle lining, which causes more inflammation, swelling and discomfort. The enzymes even destroy collagen, potentially resulting in post-acne scarring.
There are two types of acne lesions: inflammatory and noninflammatory. Inflammatory lesions are inflamed when blood penetrates the follicle after it has ruptured. The two prominent types of inflammatory acne lesions are papules and pustules. Noninflammatory lesions are open and closed comedones that are not red or inflamed.
A comedone consists of a mixture of dead cells and sebum that forms a plug in a sebaceous follicle and evolves from a microcomedone. There are two main types of comedones: open comedones and closed comedones, both categorized as noninflammatory acne lesions because they are not red and inflamed. Open comedones are also known as blackheads—dilated follicles in which oxygen has oxidized the sebum. Closed comedones are commonly known as a whiteheads.