title: Postinflammatory hyperpigmentation associated with treatment of solar lentigines using a Q-Switched 532-nm Nd: YAG laser: a multicenter survey.
abstract: OBJECTIVE
  To characterize the risk factors of Korean patients for postinflammatory hyperpigmentation (PIH) during treatment of solar lentigines using a Q-switched 532-nm Nd: YAG (QS 532 NY) laser.
  
  
  METHODS
  The present retrospective multicenter study was conducted at the dermatology clinics of five tertiary hospitals in Korea. Between October 2007 and January 2013, 516 patients were enrolled and reviewed for clinical features and factors associated with PIH.
  
  
  RESULTS
  The overall incidence of PIH was 20.3%. We demonstrated that patients with erythematous lentigines presented with PIH more frequently compared with those without erythematous lentigines. Among several coexisting conditions, facial diffuse dyschromia was significantly associated with PIH. Furthermore, PIH occurred more frequently in patients with invisible pores and velvety skin. However, age, sex, Fitzpatrick skin's phototype and season of treatment showed little association with PIH.
  
  
  CONCLUSIONS
  When a QS 532 NY laser is used to treat individuals with erythematous lentigines, invisible pores and velvety skin, and facial diffuse dyschromia, clinicians should be cautious and consider preventive measures.
authors: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors: Hyun Ji
authors: http://orcid.org/0000-0002-6279-2117
authors: HJ
authors: Kang
authors: b Department of Dermatology , Seoul National University Bundang Hospital , Seoul , Korea.
authors: Jung Im
authors: JI
authors: Na
authors: c Department of Dermatology , Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul , Korea.
authors: Jong Hee
authors: JH
authors: Lee
authors: d Department of Dermatology , Seoul National University Bundang Hospital , Seoul , Korea.
authors: Mi Ryung
authors: MR
authors: Roh
authors: e Department of Dermatology , Hanyang University College of Medicine , Seoul , Korea.
authors: Joo Yeon
authors: JY
authors: Ko
authors: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors: Sung Eun
authors: SE
authors: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D005260:Female; D006801:Humans; D017495:Hyperpigmentation / Q000453:epidemiology / Q000209:etiology; D015994:Incidence; D053844:Lasers, Solid-State / Q000009:adverse effects / Q000627:therapeutic use*; D007911:Lentigo / Q000532:radiotherapy*; D028022:Low-Level Light Therapy; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D062606:Tertiary Care Centers; D055815:Young Adult
keywords: Postinflammatory hyperpigmentation; Q-switched 532-nm Nd: YAG laser; solar lentigo