Reviewed by Michael Fuller, M.D.Acne is a skin disorder that can affect the face, neck, upper chest, back, and buttocks with lesions commonly known as “pimples”. The disorder starts in the sebaceous gland and the hair follicle to which it is attached, together making up the pilosebaceous unit. In normal skin, the sebaceous gland produces an oily substance called sebum, which travels up the follicular canal and is released through the pore onto the skin surface. The skin cells lining the hair follicle are shed and are also released through the skin’s pores. In acne, dead skin cells and sebum clog the follicular canal and produce a comedo (koh-me-doh, plural = comedones). If this comedo becomes inflamed, it can become a papule, pustule, nodule, or even cyst. The severity of acne ranges from mild cases that can be controlled with over-the-counter products to severe cases that require the attention of a dermatologist.
Acne is one of the most common skin disorders in the U.S. with over 60 million Americans affected. Eighty- five percent of all teenagers suffers from acne, but this disorder is not limited to adolescents. Approximately 20% of adults have acne as well. Acne affects men and women of all races and skin types. It typically starts at an early age-- as young as ten years old-- and usually goes away on its own by the late teens or early 20’s. For some people, their first bout of acne is in adulthood. Although there are exceptions, acne tends to occur earlier in females and last longer, while males may have a later onset but more severe course. Genetics play an important role in determining one’s individual experience with acne.Three main factors contribute to the formation of acne: androgenic hormones, plugging of the hair follicle, and bacteria. It is not surprising that acne first develops during puberty when hormone levels, particularly androgens, are circulating at high levels. Androgenic hormones stimulate sebaceous glands to enlarge and increase sebum production. The excess sebum joins the sticky debris from dead skin cells to clog hair follicles which then leads to the formation of comedones. The clogged follicle is a friendly environment for the bacteria Propionibacterium acnes (P. acnes). These bacteria break down the lipids found in sebum into free fatty acids which are thought to be irritating to the skin, resulting in inflammation. P. acnes also attract neutrophils, white blood cells that play a role in fighting infection, to the site of the clogged follicle. In addition to these causative factors, many factors may aggravate acne. These include: stress, fluctuating hormone levels (for instance, in pregnancy), certain medications, and ingredients found in skin products.
There are two major categories of acne: non-inflammatory and inflammatory. The non- inflammatory lesions are either closed comedones (“whiteheads”) or open comedones (“blackheads”). Closed comedones are small, flesh-colored or slightly red bumps that are caused by follicles containing a plug of sebum and keratinous debris. The pore is closed or small and difficult to see. In contrast, open comedones appear black on the surface of the skin because the pore is open and distended which makes the plug visible. The exposed black surface of the plug is caused by the skin’s natural dark pigment melanin and should not be confused with dirt. In inflammatory acne, comedones develop in the same way as in non-inflammatory acne, but they then become infected with bacteria which triggers an inflammatory response by the body’s immune system. As white blood cells swarm to the infected area, the comedone swells to produce a larger bump called a papule that can be tender. As more inflammation occurs, pus accumulates at the surface of the skin to form a pustule. The most severe inflammatory acne causes nodules and “cystic” lesions which can be very prominent, painful, and permanently scarring.
Certain medications can cause or aggravate acne. Several of these include anabolic steroids, lithium, anti- seizure medications, and iodinated substances. “Steroid acne” is an acne- like skin condition caused by oral or topical corticosteroids. It usually disappears once the medication is discontinued. Do not discontinue medications prescribed for medical illnesses on your own, but instead ask your physician for options that may be less prone to aggravating your acne.
Although there is no cure for acne, there are many ways to prevent it and keep it under control until the end of its natural course. Treatment can be divided into four main categories: topical agents, systemic antibiotics, systemic retinoids, and hormonal therapy. Topical drugs affect the local area on which they are applied (i.e., the skin surface), while systemic drugs are usually either taken by mouth or injected and affect the entire body. In general, a particular acne therapy should be tried for 2 months, and if there is no improvement, more intensive therapy can be prescribed in a step- wise fashion. For severe cases of acne, your physician may choose to start directly with oral retinoids to minimize scarring from acne. Injectable corticosteroids can also be used on very resistant individual lesions. It may be tempting to quit treatment because results are not quickly seen, but the key to successful control of acne is through consistent adherence to your therapy. Also, it may be necessary to continue therapy beyond when your existing acne lesions have improved or disappeared in order to prevent new lesions from forming. Remember, there is no “magic cure” for acne, but with the right therapy and persistence, acne can become a manageable part of your life.
Click here to learn about 7 Acne Myths.
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