A clinical study of carbon dioxide lattice laser-assisted or microneedle-assisted 5-aminolevulinic acid-based photodynamic therapy for the treatment of hypertrophic acne scars

Photodermatol Photoimmunol Photomed. 2022 Jan;38(1):53-59. doi: 10.1111/phpp.12716. Epub 2021 Jul 17.


Objective: To study the clinical efficacy, recurrence rate and safety of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) combined with microneedle or CO2 lattice laser (CO2FL), in comparison with intrascar betamethasone injection in the treatment of hypertrophic acne scar.

Methods: Fifty-two patients with hypertrophic acne scars at the mandibular angle were enrolled and assigned to different therapy groups. Sixteen patients were treated with microneedle-assisted incorporation of ALA. Twenty-eight patients underwent CO2FL-assisted incorporation of ALA. Eight patients received standard therapy with intrascar injection of glucocorticoid. Two dermatologists, blinded to the therapy groups, independently evaluated the scars in all patients using the average value of the Vancouver Scar Scale score, which was treated as an integer variable.

Results: After three rounds of treatment, there was no significant difference in therapeutic effective rate among the microneedle, laser and topical glucocorticoid groups (93.75% vs 100% vs 100%, P = .855). One out of 16 patients (6.25%) in the microneedle group, no patient (0%) in the laser group and two out of eight patients (25%) in the topical glucocorticoid group had recurrence. The laser group showed a higher rate of adverse effects, which were usually mild and reversible, except for pigmentation. Adverse reactions could be completely subsided within 3 weeks.

Conclusions: Either CO2FL or microneedle combined ALA-PDT for hypertrophic scar, as to topical glucocorticoid therapy, showed equivalent clinical effects but lower recurrence rate within 6 months of follow-up period.

Keywords: carbon dioxide fractional laser; hypertrophic acne scar; microneedle; photodynamic therapy.

MeSH terms

  • Acne Vulgaris* / complications
  • Acne Vulgaris* / drug therapy
  • Aminolevulinic Acid
  • Carbon Dioxide
  • Cicatrix, Hypertrophic* / drug therapy
  • Cicatrix, Hypertrophic* / etiology
  • Cicatrix, Hypertrophic* / pathology
  • Humans
  • Lasers, Gas*
  • Photochemotherapy*
  • Treatment Outcome


  • Carbon Dioxide
  • Aminolevulinic Acid