A systematic review of 33 studies evaluating nonpharmacological treatments for acne provided what was described as “circumstantial” evidence of efficacy by the authors who conducted the analysis.

The 33 studies evaluated three types of treatments: laser-based and light-based treatments (20), chemical peels (11), and fractional microneedling radiofrequency (2); most were associated with significant reductions in acne lesions in the studies. The evidence for efficacy was “strong” for glycolic acid at concentrations from 10% to 40%, and “moderate” for amino fruit acids at concentrations of 20%-60%, for intense pulsed light (IPL: 400-700 and 870-1,200 nm), and for the diode laser 1450 nm, according to F.M.C. de Vries, MD, of the department of dermatology, Radboud University, Nijmegen, the Netherlands, and coauthors.

However, they added, “although a high rate of statistically significant results was found in most of the studies, indicating efficacy of nonpharmacological therapies, the low methodological quality of the included studies made it difficult to draw clear conclusions.” Most of the studies were limited by factors that included a small number of enrolled participants, short follow-up, and lack of or possibly inadequate blinding in participants and/or clinicians.

Their review of three electronic databases (MEDLINE, Cochrane library, CINAHL) identified the 33 studies evaluating these treatments in 1,404 participants with acne, published between January 2000 and May 2017, which met their inclusion criteria.

Most of the studies on laser- and light-based treatments found a “significant reduction in acne lesions,” including eight that had a control group. However, with two exceptions, “suboptimal methodologic quality of the majority of these studies resulted in limited evidence of efficacy,” they added. The exceptions were two studies that were the basis of their “moderate” rating for IPL and the diode laser: a randomized study of IPL (40-700 and 870-1,200 nm, 100 ms, 20 J/cm2, 20 ms, 18 J/cm2), which found that treatment with IPL resulted in a significant reduction in papules, pustules, and comedones, compared with controls; and a randomized controlled study that found that treatment with a diode laser (1,450 nm, 9.5-11.0 J/cm2, 29-30 ms) resulted in reductions in inflammatory acne that were statistically significant.

The agents studied in the 11 chemical peel trials included salicylic acid, glycolic acid, Jessner solution, trichloroacetic acid, mandelic acid, amino fruit acid, and lipohydroxy acids. “Strong evidence of efficacy” was evident in two studies of glycolic acid (10% and 40% concentrations), which were double-blind, randomized, placebo-controlled studies that were of “high methodological quality,” the authors wrote.

Both studies of fractional microneedling radiofrequency, which were split-face randomized controlled studies, found statistically significant effects of treatment on inflammatory and noninflammatory acne in one study, and a “substantial” reduction in papules and pustules, compared with baseline in the other study. But this evidence was considered limited, because of the “suboptimal methodological quality” of both studies, they noted.

Erythema, pain (described as “tolerable”), purpura, edema, and hyperpigmentation were among the most common adverse effects associated with the nonpharmacological treatments and were described as mild and transient in most cases.

The review provided “circumstantial evidence for nonpharmacological therapies in the treatment of acne vulgaris” and “has created order and structure in resulting outcomes in which a first step towards future research is generated,” the authors concluded. “The large amount of studies performed in the area of acne treatment and the frequent application of these therapies in daily practice indicates a great interest in this topic and the urgent demand for effective nonpharmacological treatment options for acne in addition to the use of conventional therapies,” they added.

The authors had no disclosures. Of the six authors, Dr. de Vries and three other authors are affiliated with HU University of Applied Sciences, Utrecht, the Netherlands, which funded the study.

SOURCE: de Vries FMC et al. J Eur Acad Dermatol Venereol. 2018 Feb 14. doi: 10.1111/jdv.14881.