Acne vulgaris is prevalent in the general population, with 40 to 50 million affected individuals in the United States.1 Severe inflammation and injury can lead to disfiguring scarring, which has a considerable impact on quality of life.2 Numerous therapeutic options for acne scarring are available, including microneedling with and without platelet-rich plasma (PRP), lasers, chemical peels, and dermal fillers, with different modalities suited to individual patients and scar characteristics. This article reviews updates in treatment options for acne scarring.
Microneedling, also known as percutaneous collagen induction or collagen induction therapy, has been utilized for more than 2 decades.3 Dermatologic indications for microneedling include skin rejuvenation,4-6 atrophic acne scarring,7-9 and androgenic alopecia.10,11 Microneedling also has been used to enhance skin penetration of topically applied drugs.12-15 Fernandes16 described percutaneous collagen induction as the skin’s natural response to injury. Microneedling creates small wounds as fine needles puncture the epidermis and dermis, resulting in a cascade of growth factors that lead to tissue proliferation, regeneration, and a collagen remodeling phase that can last for several months.8,16
Microneedling has gained popularity in the treatment of acne scarring.7 Alam et al9 conducted a split-face randomized clinical trial (RCT) to evaluate acne scarring after 3 microneedling sessions performed at 2-week intervals. Twenty participants with acne scarring on both sides of the face were enrolled in the study and one side of the face was randomized for treatment. Participants had at least two 5×5-cm areas of acne scarring graded as 2 (moderately atrophic scars) to 4 (hyperplastic or papular scars) on the quantitative Global Acne Scarring Classification system. A roller device with a 1.0-mm depth was used on participants with fine, less sebaceous skin and a 2.0-mm device for all others. Two blinded investigators assessed acne scars at baseline and at 3 and 6 months after treatment. Scar improvement was measured using the quantitative Goodman and Baron scale, which provides a score according to type and number of scars.17 Mean scar scores were significantly reduced at 6 months compared to baseline on the treatment side (P=.03) but not the control side. Participants experienced minimal pain associated with microneedling therapy, rated 1.08 of 10, and adverse effects were limited to mild transient erythema and edema.9 Several other clinical trials have demonstrated clinical improvements with microneedling.18-20
The benefits of microneedling also have been observed on a histologic level. One group of investigators explored the effects of microneedling on dermal collagen in the treatment of various atrophic acne scars in 10 participants.7 After 6 treatment sessions performed at 2-week intervals, dermal collagen was assessed via punch biopsy. A roller device with a needle depth of 1.5 mm was used for all patients. At 1 month after treatment compared to baseline, mean (SD) levels of type I collagen were significantly increased (67.1% [4.2%] vs 70.4% [5.4%]; P=.01) as well as at 3 months after treatment compared to baseline for type III collagen (61.4% [3.6%] vs 74.3% [7.4%]; P=.01), type VII collagen (15.2% [2.1%] vs 21.3% [1.2%]; P=.03), and newly synthesized collagen (14.5% [5.8%] vs 19.5% [3.2%]; P=.02). Total elastin levels were significantly decreased at 3 months after treatment compared to baseline (51.3% [6.7%] vs 46.9% [4.3%]; P=.04). Adverse effects were limited to transient erythema and edema.7
Microneedling With Platelet-Rich Plasma
Microneedling has been combined with platelet-rich plasma (PRP) in the treatment of atrophic acne scars.21 In addition to inducing new collagen synthesis, microneedling aids in the absorption of PRP, an autologous concentrate of platelets that is obtained through peripheral venipuncture. The concentrate is centrifuged into 3 layers: (1) platelet-poor plasma, (2) PRP, and (3) erythrocytes.22 Platelet-rich plasma contains growth factors such as platelet-derived growth factor, transforming growth factor (TGF), and vascular endothelial growth factor, as well as cell adhesion molecules.22,23 The application of PRP is thought to result in upregulated protein synthesis, greater collagen remodeling, and accelerated wound healing.21
Several studies have shown that the addition of PRP to microneedling can improve treatment outcome (Table 1).24-27 Severity of acne scarring can be improved, such as reduced scar depth, by using both modalities synergistically (Figure).24 Asif et al26 compared microneedling with PRP to microneedling with distilled water in the treatment of 50 patients with atrophic acne scars graded 2 to 4 (mild to severe acne scarring) on the Goodman’s Qualitative classification and equal Goodman’s Qualitative and Quantitative scores on both halves of the face.17,28 The right side of the face was treated with a 1.5-mm microneedling roller with intradermal and topical PRP, while the left side was treated with distilled water (placebo) delivered intradermally. Patients underwent 3 treatment sessions at 1-month intervals. The area treated with microneedling and PRP showed a 62.20% improvement from baseline after 3 treatments, while the placebo-treated area showed a 45.84% improvement on the Goodman and Baron quantitative scale.26
Chawla25 compared microneedling with topical PRP to microneedling with topical vitamin C in a split-face study of 30 participants with atrophic acne scarring graded 2 to 4 on the Goodman and Baron scale. A 1.5-mm roller device was used. Patients underwent 4 treatment sessions at 1-month intervals, and treatment efficacy was evaluated using the qualitative Goodman and Baron scale.28 Participants experienced positive outcomes overall with both treatments. Notably, 18.5% (5/27) on the microneedling with PRP side demonstrated excellent response compared to 7.4% (2/27) on the microneedling with vitamin C side.25