Most of us have been there -- scrubbing and cleansing and moisturizing and zapping -- desperate to get rid of those pimples that tormented the teenage (and maybe adult) years. But now a new study published in the Lancet found that common acne-fighting products lack proper research in documenting their effectiveness.
"The large number of products and product combinations, and the scarcity of comparative studies, has led to disparate guidelines with few recommendations being evidence-based," lead author Hywel Williams from the Centre of Evidence-Based Dermatology at the UK's University of Nottingham, said in a statement.
Most guidelines for acne care are based on expert opinions, but even those opinions many have conflicts of interest, the study noted.
Researchers said "almost half of recently published acne trials contain serious flaws that could be overcome by better reporting…The absence of trials with active comparators is a significant handicap to shared clinical decision making."
Medications, including retinoids, bezoyl peroxide, topical dapsone, hormonal medications like birth control pills and antibiotics, are the most common treatments for varying degrees of acne. Experts have discouraged doctors in recent years from prescribing long-term antibiotics for treatment out of fear that patients will develop resistance to the medications.
But, Dr. Kevin Cooper, professor and chair of dermatology at University Hospitals Case Medical Center in Cleveland, defended the research of many over-the-counter and prescribed acne-fighting products.
"There are many clinical trials published which demonstrate that the treatment being studied is better than placebo and has reasonable or minimal side effects," said Cooper. "This is necessary to obtain FDA approval of the medication or the medication combination. In some cases the company may have compared the combination against the individual ingredients alone."
The study's reference to "lack of research," refers to comparative effectiveness research, where two competitive products are tested head-to-head to see if one is better than the other, Cooper noted.
While the best scientific evidence for most kinds of research comes from double-blind, prospective, randomized, placebo-controlled trials, Dr. John Messmer, associate professor of family and community medicine at Penn State Hershey College of Medicine, noted that those "are hard to do with acne."
Acne is not fully understood, but dermatologists say genetics, gender, hormones, other medications, skin type and sunlight contribute to the condition. It is the most common skin disorder in the United States, affecting 40 to 50 million Americans according to the American Academy of Dermatology, and is usually caused by three common occurrences: the overproduction of oil, blockage of hair follicles that release oil and growth of bacteria within the follicles. Almost all teenagers will suffer from at least a mild acne, and about 40 to 60 percent of adults well into their 20s and 30s will suffer from some acne, according to a 2001 German study published in the British Journal of Dermatology.
"Given the complex variables that influence skin oils, bacteria and inflammatory response in different patients, it is nearly impossible to control all variables except the treatment in order to get good, high quality, evidence-based comparative research on acne," said Messmer.