title: Side effects from intense pulsed light: Importance of skin pigmentation, fluence level and ultraviolet radiation-A randomized controlled trial.
abstract: Intense pulsed light (IPL) is a mainstream treatment for hair removal. Side effects after IPL are known, but risk factors remain to be investigated. The objective of this study was to assess the contribution of skin pigmentation, fluence level, and ultraviolet radiation (UVR) on IPL-induced side effects.
  
  
  
  The study was a blinded, randomized intra-individual controlled trial including 16 healthy subjects with Fitzpatrick Skin Types (FST) II-V. Three test areas were each divided into four sites, randomized to a single IPL exposure of 22, 34, 46 J/cm2or triple stacking of 46 J/cm2. Areas were subsequently randomized to no UVR or single solar-simulated UVR exposure of 3 Standard Erythema Dose at 30 minutes or 24 hours after IPL. Each area had a corresponding control, resulting in 15 treatment sites. Follow-up visits were scheduled up to 4 weeks after IPL. Outcome measures were: (i) blinded clinical skin reactions; (ii) objectively measured erythema and pigmentation; (iii) pain measured by visual analog scale (VAS); (iv) histology (H&E, Fontana-Masson); and (v) mRNA-expression of p53.
  
  
  
  Fifteen subjects with FST II-IV completed the protocol. IPL induced a wide range of skin reactions, including erythema (87% of subjects), purpura (27%), blisters (20%), edema (13%), crusting (13%), hyper- (60%), and hypopigmentation (20%). Darker skin pigmentation and increasing IPL fluence were determinants for IPL-induced side effects (P ≤ 0.002), while a single exposure of UVR did not exacerbate side effects (P ≥ 0.180). Clinical findings were confirmed objectively by reflectance spectrometry and qualitatively by histological changes in skin architecture, inflammatory infiltration, and pigmentation. Marker of cellular DNA damage, that is, p53, did not increase after IPL (P ≥ 0.24).
  
  
  
  Skin pigmentation and IPL fluence are major determinants of side effects after IPL exposure, while a single exposure to three SED of UVR at 30 minutes or 24 hours after IPL, does not amplify such side effects. Lasers Surg. Med. 49:88-96, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, DK-2400, Copenhagen, Nordvest, Denmark.
authors.forename: Daniel
authors.initials: D
authors.lastname: Thaysen-Petersen
authors.affiliation: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, DK-2400, Copenhagen, Nordvest, Denmark.
authors.forename: Andres M
authors.initials: AM
authors.lastname: Erlendsson
authors.affiliation: The Procter & Gamble Company, Cincinnati, Ohio, 45202.
authors.forename: J F
authors.initials: JF
authors.lastname: Nash
authors.affiliation: The Procter & Gamble Company, Kronberg, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Beerwerth
authors.affiliation: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, DK-2400, Copenhagen, Nordvest, Denmark.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Philipsen
authors.affiliation: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, DK-2400, Copenhagen, Nordvest, Denmark.
authors.forename: Hans C
authors.initials: HC
authors.lastname: Wulf
authors.affiliation: Department of Dermatology, Venereology and Allergology, University of Leipzig, Leipzig, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Paasch
authors.affiliation: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, DK-2400, Copenhagen, Nordvest, Denmark.
authors.forename: Merete
authors.initials: M
authors.lastname: Haedersdal
mesh_terms: D000293:Adolescent; D000328:Adult; D001707:Biopsy, Needle; D001768:Blister / Q000209:etiology / Q000473:pathology; D004307:Dose-Response Relationship, Radiation; D004487:Edema / Q000209:etiology / Q000473:pathology; D004890:Erythema / Q000209:etiology* / Q000473:pathology; D005260:Female; D006204:Hair Removal / Q000009:adverse effects* / Q000379:methods; D064368:Healthy Volunteers; D006801:Humans; D007150:Immunohistochemistry; D028022:Low-Level Light Therapy / Q000009:adverse effects* / Q000379:methods; D008297:Male; D010147:Pain Measurement; D011446:Prospective Studies; D011829:Radiation Dosage; D018570:Risk Assessment; D016037:Single-Blind Method; D012880:Skin Pigmentation / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*; D055815:Young Adult
keywords: adverse events; hair removal; histology; melanin; p53; quantified real-time polymerase chain reaction; skin type; tanning