title: Condition known as "dark rings under the eyes" in the Japanese population is a kind of dermal melanocytosis which can be successfully treated by Q-switched ruby laser.
abstract: BACKGROUND
  In general, dark rings under the eyes are believed to be a phenomenon caused mainly by physiological change because of their daily fluctuation. Medically speaking, the precise cause or pathogenesis of dark rings is unknown, and this condition has not been clearly defined. In our experience, the dark rings associated with conventional nevus of Ota can be successfully treated with Q-switched ruby laser (QSRL).
  
  
  OBJECTIVE
  This study was conducted to clarify the nature of dark rings under the eyes and to determine the efficacy of QSRL.
  
  
  METHODS
  Fifty-four patients who received a biopsy for pigment macules of the face were retrieved, and of that number 12 patients with bilateral homogeneous pigment macule on suborbital regions were selected for study of the dark rings. Of those patients, the histology and the efficacy of QSRL were evaluated retrospectively.
  
  
  RESULTS
  Histologically, all 12 patients indicated dermal melanocytosis, which was confirmed by the Masson-Fontana silver stain and staining against S100. In five patients who received QSRL therapy two times or more, the clinical improvement of two patients was scored as good (40-69%), and two other patients as excellent (>70% clearance).
  
  
  CONCLUSIONS
  We speculate that so-called dark rings under the eyes in the Japanese population is a kind of dermal melanocytosis which can be successfully treated by QSRL.
authors.affiliation: Department of Dermatology, Teikyo University School of Medicine, Tokyo, Japan. watanabe@med.teikyo-u.ac.jp
authors.forename: Shinichi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakai
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Ohnishi
mesh_terms: D001706:Biopsy; D003937:Diagnosis, Differential; D005148:Facial Dermatoses / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy*; D005500:Follow-Up Studies; D006801:Humans; D028022:Low-Level Light Therapy / Q000379:methods*; D008548:Melanosis / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy*; D009915:Orbit; D012189:Retrospective Studies; D016896:Treatment Outcome