Histologic Study of Depressed Acne Scars Treated with Serial High-Concentration (95%) Trichloroacetic Acid

Abstract

BACKGROUND Acne scarring is a common manifestation that remains a therapeutic challenge to dermatologists, dermatologic surgeons, and plastic surgeons. Although multiple therapeutic modalities exist, treatment often remains inadequate. The use of high-concentration (95%) trichloroacetic acid (TCA) applied focally to atrophic acne scars has been described. OBJECTIVE The current study confirms the utility of focal application of 95% TCA to acne scars in addition to a histologic examination of this technique. METHODS Acne scars in three patients were treated with focal 95% TCA by serial application. Wooden applicators were used to apply TCA focally and repeated at 6-week intervals for a total of six treatments. Punch biopsies were performed at baseline and at 1 year postoperatively. Histologic examination was performed with routine hematoxylin/eosin, Masson trichrome, and Verhoeff-van Gieson staining. RESULTS Clinical examination revealed apparent cosmetic improvement in both depth and appearance of acne scars. Patient satisfaction was high. Histologic examination demonstrated a decrease in the depth of acne scars. In addition, increased collagen fibers and fragmentation of elastic fibers were noted. There were no complications from the procedure. CONCLUSION Focal application of high-concentration TCA to atrophic and “ice-pick” acne scars appears to produce clinical improvement. Histologic changes of this technique are described.