title: Melasma treatment using an erbium:YAG laser: a clinical, immunohistochemical, and ultrastructural study.
abstract: BACKGROUND
  Melasma is a common pigmentary disorder that remains resistant to available therapies.
  
  
  OBJECTIVE
  The aim of the present study was to evaluate the efficacy of erbium:YAG lasers in the treatment of refractory melasma and investigate the histopathological and ultrastructural changes between melasma skin and adjacent control skin before and after surgery.
  
  
  METHODS
  Fifteen Egyptian female patients with melasma unresponsive to previous therapy of bleaching creams and chemical peels were included in this study. Full-face skin resurfacing using an erbium:YAG laser was performed. Clinical parameters included physician and patient assessment, and melasma area and severity index score were done. Adverse effects after laser resurfacing were recorded. Biopsies of lesions and adjacent healthy skin were stained using hematoxylin-eosin, immunohistochemically marked for Melan-A, and evaluated by electron microscopy.
  
  
  RESULTS
  The amount of melanin, staining intensity, and number of epidermal melanocytes are increased in melasma lesions as compared to normal skin. Electron microscopic analysis revealed an increased number of mature melanosomes in keratinocytes and melanocytes, with more marked cytoplasmic organelles in melasma skin than in biopsy specimens from normal skin, suggesting increased cell activity. After surgery, the number of melanocytes and concentration of melanin decreased in melasma skin, and the mean melasma area and severity index score decreased dramatically.
  
  
  CONCLUSIONS
  Erbium:YAG laser resurfacing effectively improves melasma; however, the almost universal appearance of transient postinflammatory hyperpigmentation necessitates prompt and persistent intervention.
authors.affiliation: Department of Dermatology and Venereology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
authors.forename: Enayat
authors.initials: E
authors.lastname: Attwa
authors.forename: Mohamed
authors.initials: M
authors.lastname: Khater
authors.forename: Magda
authors.initials: M
authors.lastname: Assaf
authors.forename: Manal Abdel
authors.initials: MA
authors.lastname: Haleem
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D017495:Hyperpigmentation / Q000209:etiology; D015603:Keratinocytes / Q000648:ultrastructure; D053844:Lasers, Solid-State / Q000009:adverse effects / Q000627:therapeutic use*; D008543:Melanins / Q000032:analysis; D008544:Melanocytes / Q000648:ultrastructure; D008548:Melanosis / Q000378:metabolism / Q000473:pathology* / Q000601:surgery*; D020460:Melanosomes / Q000648:ultrastructure; D008875:Middle Aged; D012720:Severity of Illness Index
chemical_list: D008543:Melanins