Histologic study of depressed acne scars treated with serial high-concentration (95%) trichloroacetic acid

Dermatol Surg. 2006 Aug;32(8):985-90; discussion 990. doi: 10.1111/j.1524-4725.2006.32220.x.


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.

MeSH terms

  • Acne Vulgaris / complications*
  • Administration, Topical
  • Adult
  • Chemexfoliation*
  • Cicatrix / drug therapy*
  • Cicatrix / etiology
  • Cicatrix / pathology
  • Female
  • Humans
  • Male
  • Patient Satisfaction
  • Treatment Outcome
  • Trichloroacetic Acid / administration & dosage
  • Trichloroacetic Acid / therapeutic use*


  • Trichloroacetic Acid