title: Cutaneous effects of cryogen spray cooling on in vivo human skin.
abstract: BACKGROUND
  Despite widespread clinical use of cryogen spray cooling (CSC) in conjunction with laser dermatologic surgery, in vivo cutaneous effects have not been systematically evaluated.
  
  
  OBJECTIVE
  The authors characterize the in vivo cutaneous effects for Fitzpatrick skin types I through VI after CSC exposures of varying spurt durations and spurt delivery patterns (single vs. multiple spurts).
  
  
  METHODS
  Twenty-seven normal human subjects were exposed to single cryogen spurts from 10 to 80 milliseconds, and multiple spurt patterns consisting of two 20-millisecond spurts, four 10-millisecond spurts, and eight 5-millisecond spurts. Subjects were evaluated by clinical observation and photography at 1 hour, 1 day, and 1, 4, 8, and 12 weeks after CSC exposure.
  
  
  RESULTS
  Acute erythema and urticaria (1-24 hours) were noted in 14 of 27 and 3 of 27 subjects, respectively. Transient hyperpigmentation occurred in 4 of 27 subjects (skin types III-VI) but resolved spontaneously without medical intervention in all subjects by 8 weeks. No permanent skin changes were noted in any subjects. Skin reactions were more common with longer single-spurt durations (50 milliseconds or greater) and multiple spurt patterns.
  
  
  CONCLUSIONS
  Acute erythema, urticaria, and, less commonly, transient hyperpigmentation were observed after CSC exposure. Permanent skin injury was not observed and is unlikely.
authors.affiliation: Beckman Laser Institute, Irvine, California 92612, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Datrice
authors.forename: Julio
authors.initials: J
authors.lastname: Ramirez-San-Juan
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Azin
authors.initials: A
authors.lastname: Meshkinpour
authors.forename: Guillermo
authors.initials: G
authors.lastname: Aguilar
authors.forename: J Stuart
authors.initials: JS
authors.lastname: Nelson
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Kelly
mesh_terms: D000287:Administration, Topical; D000336:Aerosols / Q000008:administration & dosage / Q000494:pharmacology; D017679:Cryotherapy / Q000009:adverse effects / Q000379:methods*; D005466:Fluorocarbons / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D028022:Low-Level Light Therapy; D012867:Skin / Q000293:injuries* / Q000528:radiation effects; D012880:Skin Pigmentation / Q000528:radiation effects
chemical_list: D000336:Aerosols; D005466:Fluorocarbons; C015531:tetrafluoroethylene