Microneedling With Glycolic Acid or Trichloroacetic Acid for Atrophic Acne Scars

Overview

Atrophic acne scars are depressed scars that can remain after acne has healed. Microneedling is a procedure that uses very small needles to create controlled micro-injuries in the skin, which may stimulate collagen production and improve scar appearance. Chemical peels, including glycolic acid and trichloroacetic acid, may also improve acne scars. This study compares three approaches for treating atrophic acne scars: microneedling followed by a 35% glycolic acid peel, microneedling followed by a 15% trichloroacetic acid peel, and microneedling alone. Sixty adults with atrophic acne scars are randomly assigned to one of the three groups. Participants receive a series of microneedling treatments at 2-week intervals. The study evaluates changes in scar severity, participant satisfaction, treatment-related pain, recovery time after treatment, and side effects. The findings may help identify whether adding either chemical peel to microneedling provides greater benefit than microneedling alone and whether one combination has a shorter recovery time or fewer side effects.

Atrophic acne scars are a common long-term consequence of acne vulgaris. They may appear as ice-pick, boxcar, or rolling scars and can affect facial appearance and quality of life. Available treatments include microneedling, chemical peeling, laser procedures, dermabrasion, subcision, and other scar-directed interventions. The choice of treatment may depend on scar morphology, skin type, recovery time, cost, and risk of adverse effects. Microneedling creates controlled microchannels in the skin and may promote dermal remodeling through wound-healing mechanisms, including fibroblast activation and new collagen formation. Glycolic acid is a superficial chemical peeling agent that promotes epidermal exfoliation and remodeling. Trichloroacetic acid produces controlled protein coagulation and a wound-healing response. Combining microneedling with chemical peeling may provide complementary effects on atrophic acne scars. This single-center randomized controlled study was conducted in the Dermatology and Venereology Department at Kafrelsheikh University Hospitals. A total of 60 adults with atrophic acne scars were allocated equally to one of three groups: microneedling followed by 35% glycolic acid peeling, microneedling followed by 15% trichloroacetic acid peeling, or microneedling alone. Microneedling was performed with a Dermapen device after topical anesthetic application and skin cleansing. In the glycolic acid group, a 35% glycolic acid peel was applied immediately after microneedling and neutralized according to the clinical endpoint and participant tolerance. In the trichloroacetic acid group, a 15% trichloroacetic acid peel was applied immediately after microneedling until an appropriate frosting endpoint was observed. The microneedling-alone group received no chemical peel. Participants received post-procedure instructions that included sun avoidance, sunscreen use, moisturizer as needed, and topical antibiotic use for 3 days. Standardized facial photographs were obtained before and after treatment and during follow-up. Two dermatologists who were blinded to treatment allocation assessed clinical response by comparing standardized photographs. The study also collected participant-reported satisfaction, procedure-related pain, post-procedure downtime, and treatment-related adverse effects, including prolonged erythema and post-inflammatory hyperpigmentation. The study evaluates whether microneedling combined with either 35% glycolic acid or 15% trichloroacetic acid can improve atrophic acne-scar severity more than microneedling alone. It also compares the two combination approaches with respect to treatment tolerance, recovery time, participant satisfaction, and safety.