Chemical peels are widely used in the treatment of acne scarring.40 Peels improve scarring through destruction of the epidermal and/or dermal layers, leading to skin exfoliation, rejuvenation, and remodeling. Superficial peeling agents, which extend to the dermoepidermal junction, include resorcinol, tretinoin, glycolic acid, lactic acid, salicylic acid, and trichloroacetic acid (TCA) 10% to 35%.41 Medium-depth peeling agents extend to the upper reticular dermis and include phenol, TCA 35% to 50%, and Jessner solution (resorcinol, lactic acid, and salicylic acid in ethanol) followed by TCA 35%.41 Finally, the effects of deep peeling agents reach the mid reticular dermis and include the Baker-Gordon or Litton phenol formulas.41 Deep peels are associated with higher rates of adverse outcomes including infection, dyschromia, and scarring.41,42
An RCT was performed to evaluate the use of a deep phenol 60% peel compared to microneedling with a 1.5-mm roller device plus a TCA 20% peel in the treatment of atrophic acne scars.43 Twenty-four patients were randomly and evenly assigned to both treatment groups. The phenol group underwent a single treatment session, while the microneedling plus TCA group underwent 4 treatment sessions at 6-week intervals. Both groups were instructed to use daily topical tretinoin and hydroquinone 2% in the 2 weeks prior to treatment. Posttreatment results were evaluated using a quartile grading scale. Scarring improved from baseline by 75.12% (P<.001) in the phenol group and 69.43% (P<.001) in the microneedling plus TCA group, with no significant difference between groups. Adverse effects in the phenol group included erythema and hyperpigmentation, while adverse events in the microneedling plus TCA group included transient pain, edema, erythema, and desquamation.43
Another study compared the use of a TCA 15% peel with microneedling to PRP with microneedling and microneedling alone in the treatment of atrophic acne scars.44 Twenty-four patients were randomly assigned to the 3 treatment groups (8 to each group) and underwent 6 treatment sessions with 2-week intervals. A roller device with a 1.5-mm needle was used for microneedling. Microneedling plus TCA and microneedling plus PRP were significantly more effective than microneedling alone (P=.011 and P=.015, respectively); however, the TCA 15% peel with microneedling resulted in the largest increase in epidermal thickening. The investigators concluded that combined use of a TCA 15% peel and microneedling was the most effective in treating atrophic acne scarring.44
Dermal or subcutaneous fillers are used to increase volume in depressed scars and stimulate the skin’s natural production.45 Tissue augmentation methods commonly are used for larger rolling acne scars. Options for filler materials include autologous fat, bovine, or human collagen derivatives; hyaluronic acid; and polymethyl methacrylate microspheres with collagen.45 Newer fillers are formulated with lidocaine to decrease pain associated with the procedure.46 Hyaluronic acid fillers provide natural volume correction and have limited potential to elicit an immune response due to their derivation from bacterial fermentation. Fillers using polymethyl methacrylate microspheres with collagen are permanent and effective, which may lead to reduced patient costs; however, they often are not a first choice for treatment.45,46 Furthermore, if dermal fillers consist of bovine collagen, it is necessary to perform skin testing for allergy prior to use. Autologous fat transfer also has become popular for treatment of acne scarring, especially because there is no risk of allergic reaction, as the patient’s own fat is used for correction.46 However, this method requires a high degree of skill, and results are unpredictable, generally lasting from 6 months to several years.
Therapies on the horizon include autologous cell therapy. A multicenter, double-blinded, placebo-controlled RCT examined the use of an autologous fibroblast filler in the treatment of bilateral, depressed, and distensible acne scars that were graded as moderate to severe.47 Autologous fat fibroblasts were harvested from full-thickness postauricular punch biopsies. In this split-face study, 99 participants were treated with an intradermal autologous fibroblast filler on one cheek and a protein-free cell-culture medium on the contralateral cheek. Participants received an average of 5.9 mL of both autologous fat fibroblasts and cell-culture medium over 3 treatment sessions at 2-week intervals. The autologous fat fibroblasts were associated with greater improvement compared to cell-culture medium based on participant (43% vs 18%), evaluator (59% vs 42%), and independent photographic viewer’s assessment.47
Acne scarring is a burden affecting millions of Americans. It often has a negative impact on quality of life and can lead to low self-esteem in patients. Numerous trials have indicated that microneedling is beneficial in the treatment of acne scarring, and emerging evidence indicates that the addition of PRP provides measurable benefits. Similarly, the addition of PRP to laser therapy may reduce recovery time as well as the commonly associated adverse events of erythema and pain. Chemical peels provide the advantage of being easily and efficiently performed in the office setting. Finally, the wide range of available dermal fillers can be tailored to treat specific types of acne scars. Autologous dermal fillers recently have been used and show promising benefits. It is important to consider desired outcome, cost, and adverse events when discussing therapeutic options for acne scarring with patients. The numerous therapeutic options warrant further research and well-designed RCTs to ensure optimal patient outcomes.