(BQ) Part 1 book Cosmetic medicine & surgery has contents: Body dysmorphic disorder, pathophysiology of skin aging, clinical signs of aging, stem cells and growth factors, cosmetics and cosmeceuticals, alle rgic risks to cosmetics and hypersensitive skin,.... and other contents.
Cosmetic Medicine & Surgery Cosmetic Medicine & Surgery Edited by Pierre André, MD Paris Université Laser Skin Clinic, Paris, France Eckart Haneke, MD Department of Dermatology, University of Bern, Switzerland Dermatology Practice Dermaticum, Freiburg, Germany Department of Dermatology, University of Ghent, Belgium Centro de Dermatologia Epidermis, Porto, Portugal Leonardo Marini, MD Skin Doctors’ Centre, Trieste, Italy Christopher Rowland Payne, MBBS, MRCP The London Clinic, London, UK Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2016 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S Government works Printed on acid-free paper Version Date: 20160923 International Standard Book Number-13: 978-1-4822-0809-2 (Pack - Book and Ebook) This book contains information obtained from authentic and highly regarded sources Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint Except as permitted under U.S Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400 CCC is a not-for-profit organization that provides licenses and registration for a variety of users For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com Contents Contributors����������������������������������������������������������������������������������������������������������������������������� ix PART I: FUNDAMENTAL ASPECTS What is beauty? A historical excursus through a continuously evolving subjective and objective perception Eckart Haneke Body dysmorphic disorder Marie-France Mihout Pathophysiology of skin aging 11 Laurent Meunier Clinical signs of aging 17 Claire Beylot Stem cells and growth factors 29 Klaus Sellheyer Adipose tissue: Development, physiology, and pathophysiology 43 Max Lafontan How to evaluate aging skin: Tools and techniques 59 Sophie Mac-Mary, Jean-Marie Sainthillier, and Philippe Humbert The aesthetic consultation 67 Christopher M.E Rowland Payne and Uliana Gout PART II: COSMETIC ASPECTS Cosmetics and cosmeceuticals 77 Martina Kerscher and Heike Buntrock 10 Photoprotection 89 Brian L Diffey 11 Allergic risks to cosmetics and hypersensitive skin 99 An E Goossens and Martine Vigan 12 Hormones and the skin 107 Gérald E Piérard, Claudine Piérard-Franchimont, and Trinh Hermanns-Lê 13 Diet and the skin 113 Alessandra Marini 14 The red face 119 Tamara Griffiths 15 Pigmentation of the face 125 Lara Tripo, Alice Garzitto, and Ilaria Ghersetich vi Contents 16 Makeup techniques in dermatology 131 Zoe Diana Draelos 17 Nail care, nail modification techniques, and camouflaging strategies 139 Bertrand Richert, Christel Scheers, and Josette André 18 Focal hyperhidrosis: Diagnosis, treatment, and follow-up 155 Oliver Kreyden 19 Cosmetic tattooing 173 Nicolas Kluger 20 Body piercings 179 Nicolas Kluger PART III: MINIMALLY INVASIVE SURGERY 21 Office surgery for dermatologists 191 Leonardo Marini 22 Aesthetic suture techniques 207 Eckart Haneke 23 Dressing systems in cosmetic dermatology 219 Maurice J Dahdah and Bertrand Richert 24 Local anesthesia for dermatological surgery 225 José J Pereyra-Rodriguez, Javier Domínguez Cruz, and Julian Conejo-Mir 25 Management of abnormal scars 233 Roland Kaufmann, Eva Maria Valesky, and Markus Meissner 26 Cosmetic surgery of the scalp 249 Pierre Bouhanna 27 Endovascular procedures for treating chronic venous insufficiency 267 Claude Garde 28 Phlebectomy 277 Albert-Adrien Ramelet 29 Nail surgery 287 Eckart Haneke 30 Superficial and medium-depth chemical peels 303 Nicolas Bachot, Christopher M.E Rowland Payne, and Pierre André 31 Deep peels 313 Nicolas Bachot, Philippe Evenou, and Pierre André 32 Combination chemical peels 319 Philippe Deprez and Evgeniya Ranneva 33 Dermabrasion 327 Anthony V Benedetto 34 41-Laser dermatology 341 Serge Mordon and Geneviève Bourg-Heckly 35 Surgical lasers: Ablative and fractional devices 357 Krystle Wang and Nazanin Saedi 36 Nonablative lasers 371 Jean-Michel Mazer Contents 37 Intense pulsed light 377 Hugues Cartier, A Le Pillouer-Prost, and Saib Norlazizi 38 Photobiomodulation and light-emitting diodes 395 Michele Pelletier-Aouizérate 39 Radiofrequency 417 Ines Verner and Boris Vaynberg 40 Fundamentals of ultrasound sources 425 Shlomit Halachmi and Moshe Lapidoth 41 Lasers for tattoo removal 433 Isabelle Catoni, Tiago Castro, and Mario A Trelles 42 Laser and pigmented (melanotic) lesions 473 Thierry Passeron 43 Lasers, intense pulsed light, and skin redness 481 Agneta Troilius Rubin 4 Laser and veins 493 Karin de Vries, Renate R van den Bos, and Martino H.A Neumann 45 Lasers and intense pulsed light for hair reduction 501 Valéria Campos, Luiza Pitassi, and Christine Dierickx 46 Photodynamic therapy for aesthetic indications 511 Colin A Morton, Rolf-Markus Szeimies, and Lasse R Braathen 47 Nonsurgical skin tightening 517 Ashraf Badawi 48 Cellulite and non-surgical fat destruction 525 Philippe Blanchemaison and Jade Frucot 49 Cryolipolysis 537 Hernán Pinto 50 Botulinum toxins: Uses in cutaneous medicine 547 Uwe Wollina 51 Cosmetic botulinum toxin treatment 557 Christopher M.E Rowland Payne and Wolfgang G Philipp-Dormston 52 Complications and pitfalls of cosmetic botulinum toxin treatment 581 Christopher M.E Rowland Payne 53 History of soft-tissue augmentation 591 Pierre André, Raphael André, and Eckart Haneke Mesotherapy 599 Philippe Petit and Philippe Hamida-Pisal 55 Hyaluronic acid: Science, indications, and results 617 Pierre André and Gürkan Kaya 56 Complications of fillers 627 Eckart Haneke 57 Platelet-rich plasma from science to clinical results 645 Sabine Zenker 58 Fat grafting 655 Olivier Claude and Pierre André vii viii Contents 59 Liposuction 663 Daniela Pulcini and Olivier Claude 60 Laser lipolysis 673 Franck Marie P Leclère, Serge Mordon, and Mario A Trelles 61 Soft tissue lifting by suspension sutures 677 Konstantin Sulamanidze, Marlen Sulamanidze, and George Sulamanidze 62 Blepharoplasty 691 Serge Morax PART IV: THE AESTHETIC FACELIFT 63 Facelift: Identity and attractiveness reconstruction 705 Thierry Besins Development of a therapeutic program: Some rules 707 Thierry Besins 65 Practical anatomy for face-lifts 709 Philippe Kestemont and Jose Santini 66 Surgical rejuvenation: Cervico-facial lift technique using the superficial musculoaponeurotic plane technique 717 Philippe Kestemont and Jose Santini 67 Surgical rejuvenation: The temporal lift 723 Henry Delmar and Thierry Besins 68 Surgical rejuvenation: Endoscopic brow lift 731 Henry Delmar 69 Surgical rejuvenation: The midface lift 733 Henry Delmar 70 Surgical rejuvenation: Autologous adipose grafting 751 Henry Delmar 71 Positive and negative aspects of face and eyelid cosmetic surgery 757 Thierry Besins 72 Current and future options for the facelift 759 Thierry Besins PART V: OTHER ASPECTS 73 Training in aesthetic and cosmetic dermatology 763 Argyri Kapellari, Panagiota Riga, and Andreas Katsambas 74 Aesthetic technician 767 Alexandre Ostojic and Ewa Guigne 75 Internet and e-consultation in aesthetic and cosmetic dermatology 771 Leonardo Marini 76 Fundamentals of managing and marketing a cosmetic dermatology clinic in the modern world 779 Wendy Lewis 77 Legal considerations in aesthetic and cosmetic dermatology 789 David J Goldberg Index 795 Contributors Josette André Department of Dermatology, St Pierre–Brugmann and Children’s University Hospitals, Université Libre de Bruxelles, Brussels, Belgium Pierre André Paris Université Laser Skin Clinic, Paris, France Raphael André Geneva University, Geneva, Switzerland Nicolas Bachot Private Practice, Paris, France Ashraf Badawi Laser Institute, Cairo University, Giza, Egypt; Szeged University, Szeged, Hungary; Laser Consultant, Toronto, Ontario, Canada; and European Society for Laser Dermatology, Strasbourg, France Anthony V Benedetto Department of Dermatology, Perelman School of Medicine, University of Pennsylvania; and Dermatologic SurgiCenter, Philadelphia, Pennsylvania Thierry Besins Department of Plastic Surgery, Clinique St George, Nice, France Claire Beylot Department of Dermatology, Bordeaux University, Bordeaux, France Philippe Blanchemaison Department of Vascular Medicine, University of Paris V, Paris, France Pierre Bouhanna Hair Transplant Clinic, Paris, France Geneviève Bourg-Heckly Laboratoire Jean Perrin, Université Pierre et Marie Curie–Paris, Paris, France Lasse R Braathen University degli Studi Guglielmo Marconi, Rome, Italy; and Dermatology Bern, Bern, Switzerland Heike Buntrock Division of Cosmetic Science, Department of Chemistry, University of Hamburg, Hamburg, Germany Valéria Campos Department of Dermatology, University of Mogi das Cruzes, Mogi das Cruzes, Brazil; and Department of Dermatology and Laser, University of Jundiai, Jundiai, Brazil Hugues Cartier Centre Médical Saint-Jean, Saint-Jean, France Tiago Castro Laser Division, Instituto Médico Vilafortuny, Cambrils, Spain Isabelle Catoni Cabinet de Dermatologie Esthétique et Laser, Neuilly sur Seine, France Olivier Claude Clinique Nescens Spontini, Paris, France Julian Conejo-Mir Medical-Surgical Dermatology Department, Virgen del Rocio University Hospital, Sevilla, Spain Maurice J Dahdah Dermatology Department, American University of Beirut, Beirut, Lebanon Karin de Vries Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands Copyright Material – Provided by Taylor & Francis Review Copy – Not for Redistribution MEDpress-Inform Publishers, 1-3-4/H, build.1, Kochnovsky proezd, RC "Aerobus", 125319 Moscow, Russia 362 AESTHETIC AND COSMETIC PRACTICE (a) (c) (b) (d) Figure 35.1 Fractionated CO2 laser treatment (Fraxel re:pair) for photoaging (a, b) Significant rhytides apparent pretreatment (c, d) Improvement in texture, dyspigmentation, and rhytides month posttreatment (Courtesy of Christopher Zachary.) light (IPL) with NAFP for photoaging treatment Mezzana and Valeriani showed greater improvement with FP followed by IPL than with FP alone [93] Similarly, Kearney and colleagues found a greater effect when IPL was combined with a 1550 nm FP for photoaging than either treatment alone [94] In addition to photoaging, FP has proven to be effective in the treatment of Poikiloderma of Civatte in one case report [95] AFP has shown significantly greater degrees of improvement in photoaging compared to NAFP In 2007, Hantash and colleagues first described the use of a novel AFP device Immunohistochemical stains from the initial in vivo studies revealed a wound remodeling response induced by adjacent intact skin that was sustained for at least 3 months posttreatment Subsequent studies have confirmed greater clinical improvements in skin texture and wrinkling achieved with AFP than with FP In addition to improving photoaging of the general face, perioral and periocular rhytides have shown particular promise with AFP Recently, Tierney and colleagues studied 25 patients in a prospective, single-blinded study for lower eyelid laxity They noted a significant improvement in skin texture, rhytides, and skin laxity after 2–3 treatments [96] Acne Scarring The initial studies of fractionated lasers on acne scarring were performed with NAFP devices Patients with ice pick to boxcar and rolling scars showed mean clinical improvement from 25% to 50% as assessed using digital photography [89] Atrophic-type acne scars similarly demonstrated improvement with NAFP [97] Efficacy appears reliant on successive treatments as many studies have demonstrated increased clinical improvement after consecutive NAFP treatments [98–101] Moreover, multiple laser passes seem to result in better clinical outcomes [79] A significant improvement has been shown in acne scars treated with AFP (Figure 35.2) Between AFP and NAFP in the treatment of acne scars, AFP has demonstrated superior efficacy A study compared nonablative 1550 nm fractional laser with a fractional CO2 laser in patients with acne scars and found more improvement when using the fractional CO2 laser [102] Between the two ablative fractional lasers, Er:YAG and CO2, treatment of acne scars has been comparable, but there is more treatment discomfort with the fractional CO2 laser [103] Of note, effective AFP settings for acne scarring are considered to be those with high-energy, low-density laser settings as opposed to low-energy, high-density laser settings [104] Both NAFP and AFP in the treatment of acne scarring in dark-skinned patients (Fitzpatrick skin types III–VI) have been studied In a study with 27 Korean patients, 3–5 sessions of NAFP showed excellent or significant self-assessed improvement in 89% of patients [105] For NAFP, it is recommended that darker skin phototypes have reduced passes and total treatment density to minimize PIH Increasing the total number of treatment sessions is needed to achieve maximum efficacy [106] Copyright Material – Provided by Taylor & Francis Review Copy – Not for Redistribution MEDpress-Inform Publishers, 1-3-4/H, build.1, Kochnovsky proezd, RC "Aerobus", 125319 Moscow, Russia Surgical lasers: Ablative and fractional devices 363 (a) (b) (c) (d) (e) Figure 35.2 (a) Fractionated CO2 laser treatment (Fraxel re:pair) for acne scars (b, c) Pretreatment (d) Visible microthermal zones (MTZs) of injury immediately following treatment (e) 4 days posttreatment month posttreatment (Courtesy of Christopher Zachary.) A study using two modes of fractional CO2 to minimize the number of treatment sessions showed a good improvement in acne scarring after one treatment session The authors suggested that using AFP as opposed to NAFP could decrease total number of treatments, yet still achieve satisfactory results Recently, combined use of fractional CO2 laser and RF waves was used to treat 15 acne-scarred patients in a pilot study with promising results [107] Acne-induced postinflammatory erythema has also shown marked improvement after one treatment session of NAFP in two patients Continued improvement was noted after multiple treatment sessions The authors speculate that Copyright Material – Provided by Taylor & Francis Review Copy – Not for Redistribution MEDpress-Inform Publishers, 1-3-4/H, build.1, Kochnovsky proezd, RC "Aerobus", 125319 Moscow, Russia 364 AESTHETIC AND COSMETIC PRACTICE the 1550 nm wavelength, which targets tissue water, destroys blood vessels and results in improved erythema [108] Other Forms of Scarring Other scars, including surgical, posttraumatic scars, and striae distensae, have responded to FP Glaich and colleagues showed improvement in long-term hypopigmented scars (5–20 years) resulting from acne and from a gas fire using the 1550 nm NAFR laser All patients reported improvement sustained for at least 3 months The authors postulated that the fractional resurfacing improved pigmentation by causing melanocytes from surrounding normal tissue to migrate and repopulate into the MTZs of injury [108] Tierney and colleagues compared NAFP with pulsed dye laser (PDL) in the treatment of patients with surgical scars and found greater improvement with NAFP They speculated that the MTZ of injury induced neocollagenesis and collagenolysis and resulted in improved scar remodeling [109] Other studies showing promising results include treatment of CO2 laser–induced hypopigmentation with AFP [110], thermal burns with FP [111–113], striae distensae with FP [114–117], and hypertrophic scars with NAFP For the latter, low-density treatments appear as effective as high-density treatments, but with the benefit of fewer side effects Study results suggest younger hypertrophic scars have more favorable outcomes [118] (Figure 35.3) Pigmentary Disorders Melasma treated with FP has shown efficacy with limitations One of the initial reports on FP in the treatment of melasma was by Rokhsar and Fitzpatrick After 4–6 treatment sessions, physician evaluation confirmed that 60% of patients achieved 75%–100% clearance [119] Promising results included one type IV skin patient demonstrating 100% clearing of melasma on the bilateral cheeks and one type V skin patient showing 75%–100% improvement Neither had any posttreatment hyperpigmentation or hypopigmentation [120] However, the patients had a high recurrence rate after treatment More recently, sustained results at 12 months were achieved using a combination of AFP and Kligman’s topical formula as (a) compared to either topical or laser alone [121] Other pigmentary disorders reported to have been successfully treated with FP include minocycline-induced hyperpigmentation [122] and Nevus of Ota [123] A recent study examining 40 patients with idiopathic guttate hypomelanosis treated with fractional CO2 laser showed promising results [124] Vascular Disorders In 2007, Glaich and colleagues reported the improvement of telangiectatic matting on a patient’s right medial thigh after 5 successive monthly treatments with NAFP [108] Similar in mechanism to improvements seen after FP treatment of Poikiloderma of Civatte and postinflammatory erythema from acne, FP is thought to specifically damage the dermal vasculature Case reports have also shown improvements in involuted hemangioma residuum from FP treatment, specifically in the flattening of fibrofatty residual tissue and in the improvement of color and texture [125–127] Other The treatment of AKs with FP has recently generated interest In 2011, Katz and colleagues reported 6-month followup data for facial AKs treated with a 1550 nm fractionated erbium-doped fiber laser after subjects underwent laser treatments Posttreatment biopsies suggested histological persistence of some AKs They concluded that FP decreased the number of clinical AKs but that the use of FP as a single-treatment modality for AKs was inadequate [128] Using FP as part of a multimodality treatment of AKs, however, appears more effective Most recently, Togsverd-Bo and colleagues reported that ablative fractional laser resurfacing followed by PDT with methyl aminolevulinate (MAL) was more effective for AK treatment in field-cancerized skin than conventional PDT with MAL They suggested that the increased efficacy was due to AFP creating vertical channels that facilitated MAL uptake and led to improved PDT efficacy [129] Isolated case reports have also shown promise in FP treating granuloma annulare [130], disseminated superficial actinic porokeratosis [131], colloid milium [132], and morphea-related contracture [133] (b) Figure 35.3 Fractionated CO2 laser treatment (Fraxel re:pair) for surgical scars (a) Pretreatment (b) Posttreatment (Courtesy of Christopher Zachary.) Copyright Material – Provided by Taylor & Francis Review Copy – Not for Redistribution MEDpress-Inform Publishers, 1-3-4/H, build.1, Kochnovsky proezd, RC "Aerobus", 125319 Moscow, Russia Surgical lasers: Ablative and fractional devices 365 PRE- AND POSTPROCEDURE CONSIDERATIONS Patient Selection When determining whether a patient is a candidate for laser resurfacing, patient selection is paramount Three areas— a complete history and physical, determination of skin type, and patient expectations—need to be thoroughly assessed Caution should be exercised in treating those with a history of delayed wound healing (including secondary to tobacco or alcohol abuse, diabetes, or any other systemic medical conditions), history of connective tissue disease, or an immunocompromised status Isotretinoin use in the past 6–12 months may also impair wound healing Patients with dermatologic diseases that demonstrate koebnerization phenomenon such as vitiligo, psoriasis, and lichen planus should be avoided if possible Special consideration should be given to any patient with active local or systemic infections and those with keloid scarring During the initial consultation, patient expectations should be established Patients should also be educated appropriately regarding the different treatment options, so that they can weigh the pros and cons and make an educated decision For instance, a single treatment with an ablative fractionated device may achieve superior results to one treatment with a nonablative fractionated device However, the former requires significant more downtime than the latter, while the latter may necessitate multiple treatments to achieve similar results to the former Most importantly, it should be stressed that there is individual-toindividual variability to treatment responses Setting reasonable expectations helps to ensure better patient satisfaction Preoperative Management and Anesthesia Various regimens have been suggested for preoperative management and anesthesia Oral antivirals are generally recommended for herpes simplex virus (HSV) prophylaxis Patients are often given antiviral prophylaxis even without documented history of an outbreak Acyclovir or valacyclovir is typically given anywhere from day prior to the morning of the treatment and continued from to 14 days after the treatment Antibacterial prophylaxis, usually in the form of penicillins or macrolides, is sometimes given as well Less commonly, antifungal prophylaxis is provided On the day of the procedure, patients are instructed to thoroughly cleanse their face with soap, water, and a terry towel For those undergoing low-energy, low-density NAFR, treatment is often initiated without anesthesia For those undergoing ablative resurfacing, various methods are employed Topical agents such as lidocaine, tetracaine, and prilocaine can be used Nerve blocks also may be utilized if needed Particularly, anxious patients may warrant additional systemic agents, including anxiolytics, anti-inflammatory agents, narcotics, or intramuscular sedation Topical anesthesia is removed prior to the procedure, roughly hour following application Postoperative Course Evaluation for adverse reactions such as blistering, sloughing, or dramatic vasospasm (clinically seen as skin whitening) should be performed during and after the procedure Topical, oral, or intramuscular steroids can be given in the postoperative period to decrease edema Verbal and written care instructions must be provided Consistent application of petrolatum-based emollient is usually recommended postoperatively; however, acneprone patients are advised to use noncomedogenic products Hydrogen peroxide or a dilute acetic acid solution can be applied to the treated area periodically to decrease crust formation and colonization with microbes For darker skin types, many dermatologists will prescribe hydroquinone 4% after the exudative phase of recovery has stopped For all patients, strict sun protection and avoidance is recommended Close followup is key as most adverse reactions occur between and 7 days following the procedure [134] COMPLICATIONS Infections Although HSV reactivation is the most common type of infection to occur after fractional laser resurfacing, reported rates range from 0.3% to 2% of cases [135,136] These rates are low, particularly when compared to those associated with NAFP, which are reported to range from 2% to 7% [137] When antiviral prophylaxis is administered to all patients regardless of their past history, the rate of patient reactivation has been shown to be less than 0.5% in healthy individuals [136] Interestingly, a recent paper reported the first cases of varicella zoster reactivation after NAFP None of the patients had taken HSV prophylaxis [138] Bacterial infection after FP appears even less common; only 0.1% of all treated cases are documented to develop impetigo [135,136] Nevertheless, caution should be exercised One should look for signs of a bacterial superinfection as delay in appropriate management can lead to scarring When there is a high index of suspicion, prompt wound culture should be performed, especially given the increased prevalence of methicillin-resistant Staphylococcus aureus A recent case of Mycobacterium chelonae infection was reported after fractionated CO2 facial resurfacing that mimicked an acneiform eruption [139] Acneiform Eruptions The rate of acneiform eruptions following NAFP has been reported to be between 2% and 10%, and milia development has been reported in as many as 19% of patients [136] It is theorized that treatment causes the abnormal reepithelialization of the follicular units, which contributes to the acneiform eruptions Occlusive dressing can further exacerbate the eruption, and noncomedogenic alternatives should be recommended if needed A short oral course of tetracylinebased antibiotics can be prescribed for more severe cases, and patients will often be prophylactically treated prior to subsequent treatments [140] Prolonged Erythema Erythema immediately posttreatment is a natural process needed for wound healing However, prolonged erythema is defined as redness that persists longer than 4 days with nonablative resurfacing and beyond month with ablative resurfacing [141] A study comparing ablative single-pass CO2 laser versus multiple-pass Er:YAG treatment showed more postoperative erythema in CO2 patients From 100 treated patients, CO2treated patients had erythema lasting an average of 4.5 weeks versus 3.6 weeks in Er:YAG-treated patients [142] In a study by Rahman and colleagues examining 30 patients, 33% experienced erythema month postfractional CO2 laser treatment By 3 months posttreatment, only 7% still had erythema [143] Copyright Material – Provided by Taylor & Francis Review Copy – Not for Redistribution MEDpress-Inform Publishers, 1-3-4/H, build.1, Kochnovsky proezd, RC "Aerobus", 125319 Moscow, Russia 366 AESTHETIC AND COSMETIC PRACTICE Studies investigating treatments that decrease postoperative erythema include the use of a 590 nm light-emitting diode array [144] and of topical ascorbic acid [145] Pigmentary Alteration From a 2010 review, PIH was reported to occur in anywhere from 1% to 32% of cases, depending on the applied system and parameters and skin phototype [141] In a study examining 500 patients, hypopigmentation occurred in