title: A retrospective study on the efficacy and complications of Q-switched alexandrite laser in the treatment of acquired bilateral nevus of Ota-like macules.
abstract: BACKGROUND
  Acquired bilateral nevus of Ota-like macules (ABNOM), or Hori's macules, is a common Asian condition that is characterized by bluish hyperpigmentation in the bilateral malar regions. Unlike nevus of Ota, ABNOM is an acquired condition that often develops after 20 years of age and involves both sides of the face, but there is no mucosal involvement. Recently Q-switched (QS) 1064 nm Nd:YAG lasers have been effective in clearing this condition. The effectiveness of QS alexandrite lasers has not yet been studied.
  
  
  OBJECTIVE
  To retrospectively assess the efficacy and complications of QS alexandrite lasers in the treatment of ABNOM.
  
  
  METHODS
  Thirty-two Chinese women with ABNOM ranging in age from 28 to 66 years were involved in the study. All underwent QS alexandrite laser treatment (755 nm, spot size 3 mm, 8 J/cm(2)). Topical hydroquinone and tretinoin cream were given to those with hyperpigmentation after the laser surgery. Clinical photographs were taken before and after laser surgery and assessed by two independent observers. The degree of clearing was scored and complications, including hypopigmentation, hyperpigmentation, scarring, and erythema, were assessed.
  
  
  RESULTS
  The mean number of treatment sessions was 7 (range 2-11) and the mean treatment interval was 33 days. Both observers identified more than 80% of the patients as having more than a 50% degree of clearing, and complete clearance was seen in more than 28% of patients. Although most patients had postlaser hyperpigmentation and were on depigmentary regimes, the hyperpigmentation was seen in only 12.5% of the patients during photographic evaluation. Hypopigmentation was seen in 50% of patients and erythema in 41%.
  
  
  CONCLUSIONS
  QS alexandrite appears to be effective in the treatment of ABNOM. Postoperative pigmentary changes were frequent and the use of topical depigmentary agents was necessary to achieve a satisfactory result. Transient hypopigmentation risk was high, affecting up to 50% of the patients. Further study is warranted to compare the efficacy and complications of different laser systems in the treatment of this condition.
authors.affiliation: Division of Dermatology, Department of Medicine, University of Hong Kong.
authors.forename: A Y
authors.initials: AY
authors.lastname: Lam
authors.forename: D S
authors.initials: DS
authors.lastname: Wong
authors.forename: L K
authors.initials: LK
authors.lastname: Lam
authors.forename: W S
authors.initials: WS
authors.lastname: Ho
authors.forename: H H
authors.initials: HH
authors.lastname: Chan
mesh_terms: D000328:Adult; D000368:Aged; D005145:Face; D005260:Female; D006801:Humans; D017495:Hyperpigmentation / Q000453:epidemiology; D017496:Hypopigmentation / Q000453:epidemiology; D053685:Laser Therapy; D008875:Middle Aged; D009507:Nevus of Ota / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome