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.
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.
