title: Role of skin cooling in improving patient tolerability of Q-switched Alexandrite (QS Alex) laser in nevus of Ota treatment.
abstract: BACKGROUND
  The development of a high-energy laser device with very short pulse duration has revolutionized the treatment of nevus of Ota. Nevertheless, patients still suffer from complications that range from the pain and swelling that occur immediately after laser surgery to post-operative pigmentary changes and scarring. However, the simultaneous use of skin surface cooling and laser surgery may limit the damage of non-target tissue.
  
  
  OBJECTIVE
  To assess whether epidermal cooling reduces the pain and swelling that commonly occur after laser treatment for nevus of Ota.
  
  
  METHODS
  Thirty-seven patients with nevus of Ota were recruited from a dermatology outpatient clinic. Before treatment, the research nurse used an ink pen to divide the lesions into two halves. Half of each lesion was treated with a Q-switched Alex laser system that had a cool sapphire plate in contact as a mean of skin cooling. The other half was treated with the same laser, but with the cooling device switched off. Immediately after treatment, and again 1 week later, the patients answered a questionnaire, which assessed the symptoms that are associated with laser surgery. Dose assessment was performed in each half of the nevus to obtain the optimal fluence that could be used for the treatment of nevus of Ota before the entire half was treated.
  
  
  RESULTS
  There was no difference in terms of the optimal fluence that was used, but in terms of immediate pain the patients associated the side that was treated with the cooling plate with a significantly lesser degree of pain than the non-cooled side (P = 0.001). Eighty two percent of the patients preferred the cooled side to the non-cooled side.
  
  
  CONCLUSIONS
  Pre- and post-operative skin cooling is effective in improving the tolerability of nevus of Ota patients to Q-switched laser treatment. However, the use of cooling during laser treatment of nevus of Ota did not allow the use of higher fluence.
authors.affiliation: Division of Dermatology, Department of Medicine, The University of Hong Kong, Hong Kong. hhlchan@hkucc.hku.hk
authors.forename: Henry H L
authors.initials: HH
authors.lastname: Chan
authors.forename: Lai-Kun
authors.initials: LK
authors.lastname: Lam
authors.forename: David S Y
authors.initials: DS
authors.lastname: Wong
authors.forename: W I
authors.initials: WI
authors.lastname: Wei
mesh_terms: D000328:Adult; D017679:Cryotherapy / Q000295:instrumentation / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D005153:Facial Neoplasms / Q000532:radiotherapy; D005157:Facial Pain / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D053685:Laser Therapy; D008297:Male; D009507:Nevus of Ota / Q000532:radiotherapy*; D017060:Patient Satisfaction; D011446:Prospective Studies; D012878:Skin Neoplasms / Q000532:radiotherapy*; D012881:Skin Temperature / Q000528:radiation effects*