title: Formation of fibrosis after nonablative and ablative fractional laser therapy.
abstract: BACKGROUND
  Fractional laser therapy (FLT) has become a widely accepted modality for skin rejuvenation and has also been used in various other skin diseases.
  
  
  OBJECTIVE
  To observe long-term histologic effects of nonablative and ablative FLT in the treatment of pigment disorders.
  
  
  METHODS
  A randomized controlled observer-blinded study was performed in 18 patients with pigment disorders. Two similar test regions were randomized to receive FLT with intermittent topical bleaching or topical bleaching alone. Patients with ashy dermatosis (AD) and postinflammatory hyperpigmentation (PIH) were treated using nonablative 1,550-nm FLT (15 mJ/microbeam, 14-20% coverage), whereas patients with Becker's nevus (BN) were treated with ablative 10,600-nm FLT (10 mJ/microbeam, 35-45% coverage) for three to five sessions. Biopsies were obtained 3 months after the last treatment.
  
  
  RESULTS
  At follow-up, dermal fibrosis was observed in four of eight patients treated using ablative FLT and no patients treated using nonablative FLT (p < .05).
  
  
  CONCLUSIONS
  Assuming that the dermal response is comparable in AD, PIH, and BN, at the given settings, ablative FLT may induce fibrosis, whereas treatment with nonablative FLT does not. Whether formation of fibrosis has to be regarded as dermal remodeling or a subtle subclinical form of scarring should be investigated in future research.
authors: Netherlands Institute for Pigment Disorders. b.s.wind@amc.uva.nl
authors: Bas S
authors: BS
authors: Wind
authors: Arne A
authors: AA
authors: Meesters
authors: Marije W
authors: MW
authors: Kroon
authors: Johan F
authors: JF
authors: Beek
authors: J P Wietze
authors: JP
authors: van der Veen
authors: Allard C
authors: AC
authors: van der Wal
authors: Jan D
authors: JD
authors: Bos
authors: Albert
authors: A
authors: Wolkerstorfer
mesh_terms: D000328:Adult; D001706:Biopsy; D005260:Female; D005355:Fibrosis / Q000209:etiology*; D006801:Humans; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D010859:Pigmentation Disorders / Q000532:radiotherapy*; D016896:Treatment Outcome