Globally, acne affects approximately 650 million people, or about 9.4% of the population, as of 2010. It affects nearly 90% of people in Western societies during their teenage years, but can occur before adolescence and may persist into adulthood. While acne that first develops between the ages of 21 and 25 is uncommon, it affects 54% of women and 40% of men older than 25 years of age, and has a lifetime prevalence of 85%. About 20% of those affected have moderate or severe cases. It is slightly more common in females than males (9.8% versus 9.0%). In those over 40 years old, 1% of males and 5% of females still have problems.
Contrary to popular belief, acne isn't caused by a harmful diet, poor hygiene, or an uncontrolled sex drive. The simple truth is that heredity and hormones are behind most forms of acne. Swearing off chocolate or scrubbing your face 10 times a day won't change your predisposition to this unsightly, sometimes painful, and often embarrassing skin problem.
Acne scars are caused by inflammation within the dermal layer of skin and are estimated to affect 95% of people with acne vulgaris. The scar is created by abnormal healing following this dermal inflammation. Scarring is most likely to take place with severe acne, but may occur with any form of acne vulgaris. Acne scars are classified based on whether the abnormal healing response following dermal inflammation leads to excess collagen deposition or loss at the site of the acne lesion.
Salicylic acid and azelaic acid. Azelaic acid is a naturally occurring acid found in whole-grain cereals and animal products. It has antibacterial properties. A 20 percent azelaic acid cream seems to be as effective as many conventional acne treatments when used twice a day for at least four weeks. It's even more effective when used in combination with erythromycin. Prescription azelaic acid (Azelex, Finacea) is an option during pregnancy and while breast-feeding. Side effects include skin discoloration and minor skin irritation.
Alternative and integrative medicine approaches used in the treatment of acne include fish oil, brewer's yeast, probiotics, oral zinc and topical tea tree oil. More research is needed to establish the potential effectiveness and long-term safety of these and other integrative approaches, such as biofeedback and traditional Chinese medicine. Talk with your doctor about the pros and cons of specific treatments before you try them.
When regular light is used immediately following the application of a sensitizing substance to the skin such as aminolevulinic acid or methyl aminolevulinate, the treatment is referred to as photodynamic therapy (PDT). Many different types of nonablative lasers (i.e., lasers that do not vaporize the top layer of the skin but rather induce a physiologic response in the skin from the light) have been used to treat acne, including those that use infrared wavelengths of light. Ablative lasers (such as CO2 and fractional types) have also been used to treat active acne and its scars. When ablative lasers are used, the treatment is often referred to as laser resurfacing because, as mentioned previously, the entire upper layers of the skin are vaporized. Ablative lasers are associated with higher rates of adverse effects compared with nonablative lasers, with examples being postinflammatory hyperpigmentation, persistent facial redness, and persistent pain. Physiologically, certain wavelengths of light, used with or without accompanying topical chemicals, are thought to kill bacteria and decrease the size and activity of the glands that produce sebum. Disadvantages of light therapy can include its cost, the need for multiple visits, time required to complete the procedure(s), and pain associated with some of the treatment modalities. Typical side effects include skin peeling, temporary reddening of the skin, swelling, and postinflammatory hyperpigmentation.