title: 420 nm intense continuous light therapy for acne.
abstract: BACKGROUND
  Topical antibiotics, isotretinoin or systemic antibiotics are usually used for acne therapy. However, isotretinoin cannot be used during pregnancy because it can cause significant birth defects while systemic antibiotics can have adverse side effects such as gastrointestinal irritation, photosensitivity and tetracycline sensitivity. Describe here is a high-intensity, narrow-band, blue light (ClearLight) system, and its therapeutic clinical effect is investigated on acne using cutaneous measurements, bacterial observations and ultrastructural changes.
  
  
  METHODS
  A total of 28 adult healthy volunteers with facial acne (mean age 28.1 years, range 16-56 years) were recruited for this study. They were treated with a total of eight serial biweekly 15-minute treatment sessions. Clinical counts of acne, as well as moisture, sebum and pH measurements were taken between each session. Nine of the 28 patients were followed for 2-3 months after the last treatment. Detection of bacteria in acne pustules was analyzed by culture and by polymerase chain reaction (PCR). Ultrastructural changes were examined in eight patients after four sessions of the light therapy.
  
  
  RESULTS
  All patients completed the study. Overall, there was a 64.7% improvement in acne lesions. There were no bacterial changes before or after the therapy, although damaged Propionibacterium acnes were observed at the ultrastructural level.
  
  
  CONCLUSIONS
  ClearLight performed eight times over 4 weeks can be useful in the treatment of acne. Further investigation will be needed to elucidate the mechanism of action of ClearLight.
authors.affiliation: Department of Dermatology, Queen's Square Medical Center, Yokohama, Japan. tom@olive.ocn.ne.jp
authors.forename: Tokuya
authors.initials: T
authors.lastname: Omi
authors.forename: Peter
authors.initials: P
authors.lastname: Bjerring
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sato
authors.forename: Seiji
authors.initials: S
authors.lastname: Kawana
authors.forename: Raleigh W
authors.initials: RW
authors.lastname: Hankins
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Honda
mesh_terms: D000152:Acne Vulgaris / Q000382:microbiology / Q000473:pathology / Q000532:radiotherapy*; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D028022:Low-Level Light Therapy; D008875:Middle Aged