title: Fractional 1,550 nm Ytterbium/Erbium fiber laser in the treatment of lichen amyloidosis: clinical and histological study.
abstract: OBJECTIVE
  Lichen amyloidosis is characterized by amyloid deposition in the papillary dermis, presenting clinically with intensely pruritic hyperkeratotic papules. Various treatment modalities have been used but the results are generally unsatisfactory. Several studies show that non-ablative fractional lasers can be used to treat depositional diseases due to their capability of inducing transepidermal elimination of the dermal content. To investigate the efficacy and safety of a non-ablative fractional 1,550 nm Yttrium/Erbium fiber laser for the treatment of lichen amyloidosis.
  
  
  METHODS
  Ten subjects with a clinical and histological diagnosis of lichen amyloidosis were treated with fractional non-ablative laser using a 7-cm tip, with the parameter of 30 mJ/cm2 and 1,000 microscopic treatment zones (MTZ)/cm2 for three sessions at 4-week intervals. Clinical improvement (in terms of global improvement score, brownish/hyperpigmentation, thickness, and number of papules) was evaluated using a quartile grading scale at baseline, and 4, 12, and 24 weeks after the last treatment. Itch score and subjective satisfaction rates were also assessed. Adverse events were recorded, and pain was scored using a visual analog scale (VAS). Histologic changes were observed using standard staining with hematoxylin and eosin, as well as special stains of alkaline congo red and crystal violet at baseline and 4 weeks after treatment.
  
  
  RESULTS
  At 4 and 24 weeks after treatment, the lichen amyloid lesions had statistically significantly improved in all aspects compared to baseline (P = 0.01 and P = 0.016, respectively; Wilcoxon signed-rank test). However, partial recurrence was reported in 2 out of 10 subjects. All subjects rated itching symptom significantly improved after only the first treatment (P < 0.05). Minimal side effects were recorded, including a burning sensation, transient erythema, and edema. Histological evaluation demonstrated decreased epidermal thickness, and degeneration and shrinkage of amyloid material deposition in the papillary dermis. There was no amyloid material deposition noted in two out of eight histopathology studies.
  
  
  CONCLUSIONS
  The non-ablative fractional 1,550 nm Ytterbium/Erbium fiber laser is safe and effective for the treatment of lichen amyloidosis. However, larger controlled studies are required to further establish the efficacy of this treatment.
authors.affiliation: Department of Medicine, Division of Dermatology, King Chulalongkorn Memorial Hospital, Bangkok, Thailand.
authors.forename: Ratchathorn
authors.initials: R
authors.lastname: Panchaprateep
authors.forename: Sai
authors.initials: S
authors.lastname: Tusgate
authors.forename: Girish S
authors.initials: GS
authors.lastname: Munavalli
authors.forename: Nopadon
authors.initials: N
authors.lastname: Noppakun
mesh_terms: D000328:Adult; D000686:Amyloidosis / Q000150:complications / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D053685:Laser Therapy; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008010:Lichen Planus / Q000150:complications / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015018:Ytterbium / Q000627:therapeutic use*
chemical_list: D015018:Ytterbium
keywords: lichen amyloidosis; non-ablative fractional laser