A Superficial Texture Analysis of 70% Glycolic Acid Topical Therapy and Striae Distensae

Abstract

Sir:FigureStriae distensae are a very diffused type of skin atrophy that cause considerable cosmetic disfigurement that is difficult to treat. Various therapeutic options are available for the purpose of improving the appearance of existing stretch marks, including surgical treatments, laser, topical therapy, and chemical peeling. Only one randomized controlled trial has been published stating that a prophylactic antistriae cream (Centella asiatica extract, α-tocopherol, and collagen-elastin hydrolysates) induced a significant absolute prevention of striae gravidarum in 89 percent of the patients studied.1 The aim of our study was to evaluate objectively, by skin texture analysis and spectrophotometry, whether the use of glycolic acid peeling improves stretch marks. We designed a double-blind controlled trial on a total of 40 patients ranging in age from 16 to 35 years. Patients were divided into two groups: those with striae rubrae (group A) and those with striae albae (group B). Each group was treated for 6 months as follows: 70% glycolic acid lotion (NeoStrata Company, Inc., Princeton, N.J.) was applied on the left thigh for 1 to 2 minutes (until erythema appeared), and placebo was applied to the right thigh. The total number of applications was six (from t0 to t6). Skin texture parameters analyzed were anisotropy, number of skin furrows, and furrow width, using the silicone replica technique, where silicone casts were analyzed by scanning electron microscopy2 and then by image software. Hemoglobin and melanin content for skin color were analyzed by means of a spectrophotometer. Pretreatment and posttreatment quantitative values from a single patient constituted a paired data set. Data expressed in numerical values have been examined by comparison among averages (time 0 and time 6) with the t test. Statistical significance was designated at value of p < 0.05. In group A, skin texture analysis of striae rubrae showed a significant decrease in furrow width after 6 months (p < 0.01). Spectrophotometric measurements showed a statistically significant decrease in hemoglobin (p < 0.01). In group B, skin texture analysis of striae albae showed a similar decrease in furrow width as striae rubrae (p < 0.01). Spectrophotometry evidenced a statistically significant increase in melanin (p < 0.01). None of the parameters in the control group showed significant differences after placebo application. Management of striae distensae is problematic and controversial. Despite the large number of studies regarding striae treatment (surgical and chemical), results remain poor. The advent of laser therapy has represented a breakthrough in the approach to striae. Laser therapy seems to be effective on striae rubrae.3 Moreover, this treatment is rather expensive, and repetitive treatment can cause pigment alteration and is not recommended for dark skin. Topical chemical treatment seems to enhance striae rubrae aspects also.4 Glycolic acid accelerates collagen synthesis by fibroblasts and modulates matrix degradation and collagen synthesis through keratinocyte-released cytokines.5 These results suggest that glycolic acid could be useful to recovery from striae distensae. The topical therapies analyzed in this study were chosen because they are readily available on the market and easy to administer. Our results emphasize that 70% glycolic acid is associated with improvement in 15 percent and after 6 months induces some stretch mark modification but does not lead to recovery in either striae rubrae or striae albae (Fig. 1).Fig. 1: (Left) Lateral thigh area of a 23-year-old woman before treatment (original magnification, × 10). Stria rubra appears as a linear lesion raised above the surrounding tissue with a different skin pattern compared with the surrounding skin. (Right) Lateral thigh area 6 months after glycolic acid topical treatment of stria rubra (original magnification, × 10). Note the flattening of the primary furrows and their transverse diameter reduction. A decrease in depth of the transverse primary sulci is noticeable.Our results emphasize objectively that glycolic acid induces only some stretch mark modifications that are perceived by the patients. These results encourage the use of peeling with glycolic acid in the treatment of stretch marks, perhaps using it over time or in combination with other topical medications. Vittorio Mazzarello, M.D. Department of BioMedical Science Francesco Farace, M.D. Department of Microsurgical Specialties–Plastic Surgery Unit Pasquale Ena, M.D. Clinical Dermatology Grazia Fenu, M.D. Department of BioMedical Science Pietro Mulas, M.D. Department of Microsurgical Specialties–Plastic Surgery Unit Luisella Piu, M.D. Department of Farmacological Science Corrado Rubino, M.D. Department of Microsurgical Specialties–Plastic Surgery Unit, University of Sassari, Sassari, Italy