title: A retrospective analysis of complications in the treatment of nevus of Ota with the Q-switched alexandrite and Q-switched Nd:YAG lasers.
abstract: BACKGROUND
  Studies on the use of Q-switched alexandrite (QS alex) and QS Nd:YAG lasers in the treatment of nevus of Ota were limited to case reports and small series. There was no study that looked at the complication rate of these systems.
  
  
  OBJECTIVE
  To retrospectively study the complication rate of nevus of Ota patients that were treated with QS alex laser, QS Nd:YAG laser, or a combination of both.
  
  
  METHODS
  The study was performed in a teaching hospital and a private hospital, where 513 patients with nevus of Ota had been treated since 1993. The 171 patients with 211 treatment sites were evaluated retrospectively following treatment with QS alex laser only (n = 58), QS Nd:YAG laser (n = 105) only, or a combination of both systems (n = 48). Patients were called back to be interviewed and examined by two independent clinicians to look for evidence of complications.
  
  
  RESULTS
  Of the treatment sites, 15. 3% had hypopigmentation, 2.9% had hyperpigmentation, and texture changes and scarring were seen in 2.9% and 1.9%, respectively. The combined treatment group was associated with a significantly higher risk of complications. Thirteen patients had recurrence of their nevus after complete or near-complete clearance with laser treatment.
  
  
  CONCLUSIONS
  Hypopigmentation is common after the use of QS laser for lightening of nevus of Ota. This particularly applies when alternate treatment with QS alex and QS Nd:YAG is used. Recurrence is an important issue and must be taken into consideration, especially when children are treated.
authors.affiliation: Division of Dermatology, Department of Medicine, University of Hong Kong, Hong Kong. hhlchan@hkucc.hku.hk
authors.forename: H H
authors.initials: HH
authors.lastname: Chan
authors.forename: R S
authors.initials: RS
authors.lastname: Leung
authors.forename: S Y
authors.initials: SY
authors.lastname: Ying
authors.forename: C F
authors.initials: CF
authors.lastname: Lai
authors.forename: T
authors.initials: T
authors.lastname: Kono
authors.forename: J K
authors.initials: JK
authors.lastname: Chua
authors.forename: W S
authors.initials: WS
authors.lastname: Ho
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000535:Aluminum; D001608:Beryllium; D002648:Child; D002675:Child, Preschool; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009354:Neodymium; D009507:Nevus of Ota / Q000150:complications* / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012878:Skin Neoplasms / Q000150:complications* / Q000601:surgery*; D012880:Skin Pigmentation / Q000528:radiation effects; D015019:Yttrium
chemical_list: C112654:alexandrite; D009354:Neodymium; D015019:Yttrium; D000535:Aluminum; D001608:Beryllium