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Laser dermatology Laser dermatology Document Transcript

  • 41D.J. Goldberg (ed.), Laser Dermatology,DOI 10.1007/978-3-642-32006-4_3, © Springer-Verlag Berlin Heidelberg 20133HistorySelective PhotothermolysisThe idea of treating cutaneous pigmented lesionswith lasers was first tested in the early 1960s byGoldman, who used a normal mode ruby laser(Goldberg and Stampien 1995). His researchindicated that the target was the melanosome.Unfortunately, due to laboratory difficulties, furtherresearch was halted.In the past 15 years, selective photothermoly-sis has largely transformed dermatologic lasersurgery. The term selective photothermolysisdescribes site-specific, thermally mediated injuryof microscopic tissue targets by selectivelyabsorbed pulses of radiation. Three basic ele-ments are necessary to achieve selective photo-thermolysis: (1) a wavelength that reaches and ispreferentially absorbed by the desired targetstructures; (2) an exposure duration less than orequal to the time necessary for cooling of the tar-get structures; and (3) sufficient fluence to reacha damaging temperature in the targets. Whenthese criteria are met, selective injury occurs inthousands of microscopic targets, without theneed to aim the laser at each one.At wavelengths that are preferentially absorbedby chromophoric structures such as melanin-con-taining cells or tattoo-ink particles, heat is createdin these targets. As soon as heat is created, how-ever, it begins to dissipate by conduction. Themost selective target heating is achieved when theenergy is deposited at a rate faster than the rate forcooling of the target structures. In contrast to dif-fuse coagulation injury, selective photothermoly-sis can achieve high temperatures at structures orindividual cells with little risk of scarring becausegross dermal heating is minimized.Z. Al-Dujaili, M.D.(*)Skin Laser and Skin Specialists of NY/NJ,New York, NY, USAe-mail: draldujaili@skinadnlasers.comC.C. Dierickx, M.D.Skin and Laser Surgery Center,Boom, Belgiume-mail: mail@cdierickx.beLaser Treatment ofPigmented LesionsZeena Al-Dujaili and Christine C. DierickxCore MessagesAccurate diagnosis of pigmented lesions•is mandatory before laser treatment. Forsome pigmented lesions, laser treatmentmay even be the only treatment option.Tattoos respond well to Q-switched•lasers.Amateur and traumatic tattoos respond•more readily to treatment than do pro-fessional tattoos.Cosmetic tattoos should be approached•with caution.Treatment of melanocytic nevi remains•controversial, but worth pursuing.
  • 42 Z. Al-Dujaili and C.C. DierickxPigmented Lesion Removal by SelectivePhotothermolysisBecause melanin absorbs light at a wide rangeof wavelengths – from 250 to 1,200 nm, severallasers or intense pulsed light sources can effec-tively treat pigmented lesions. For tattoos, lightabsorption depends on the ink color, but the pre-dominant color (blue-black) also absorbs wellthroughout the 532–1,064 nm range. Almostany laser with sufficient power can be used toremove benign pigmented lesions of the epider-mis. The selective rupture of skin melanosomeswas first noted by electron microscopy in 1983,after 351 nm, sub-microsecond excimer laserpulses of only about 1 J/cm2. At fluences dam-aging melanocytes and pigmented keratinocytes,epidermal Langerhans cells apparently escapeinjury.With regard to wavelength, absorption by mel-anin extends from the deep UV through visibleand well into the near-IR spectrum. Across thisbroad spectrum, optical penetration into skinincreases from several micrometers to severalmillimeters. One would therefore expect melano-somes and the pigmented cells containing themto be affected at different depths across this broadspectrum.A variety of thermally mediated damagemechanisms are possible in selective photo-thermolysis, including thermal denaturation,mechanical damage from rapid thermal expan-sion or phase changes (cavitation), and pyroly-sis (changes in primary chemical structure).Mechanical damage plays an important role inselective photothermolysis with high-energy,submicrosecond lasers for tattoo and pigmentedlesion removal. The rate of local heating andrapid material expansion can be so severe thatstructures are torn apart by shock waves, cavita-tion, or rapid thermal expansion.Grossly, the immediate effect of submicrosec-ond near-UV, visible, or near-IR laser pulses inpigmented skin is immediate whitening. Thisresponse correlates very well with the melano-some rupture seen by electron microscopy and istherefore presumably a direct consequence ofmelanosome rupture. A nearly identical butdeeper whitening occurs with Q-switched laserexposure of tattoos, which like melanosomesconsist of insoluble, submicrometer intracellularpigments. Although the exact cause of immediatewhitening is unknown, it is almost certainlyrelated to the formation of gas bubbles thatintensely scatter light. Over several to tens ofminutes, these bubbles dissolve, causing the skincolor to return to normal or nearly normal. Inaddition, pyrolysis may occur at the extreme tem-peratures reached within melanosomes or tattooink particles, directly releasing gases locally.Regardless of its cause, immediate whiteningoffers a clinically useful immediate endpoint thatapparently relates directly to melanosome or tat-too ink rupture (Fig. 3.1).Melanin in both the epidermis (as in cafe-au-lait macules and lentigines) and the dermis (as innevus of Ota), as well as dermal tattoo particles,is an important target chromophore for laserselective photothermolysis. Clinically, selectivephotothermolysis is highly useful for epidermaland dermal lesions in which cellular pigmenta-tion itself is a cause. These include lentigines,cafe-au-lait macules (which display a high rate ofrecurrence), Nevus spilus, Becker nevi, blue nevi,and nevus of Ota. However, selective thermolysishas only been variably effective for dermalmelasma, postinflammatory hyperpigmentation,or drug-induced hyperpigmentation.Fig. 3.1 Immediate whitening after laser treatment
  • 433 Laser Treatment of Pigmented LesionsCurrently Available TechnologyLasers and Intense Pulsed Light SourcesUsed to Treat Pigmented Lesions andTattoos (Tables 3.1,3.2,and 3.3)Continuous-Wave Lasers (CW Lasers)Although Q-switched lasers are now the modal-ity of choice for most pigmented lesions, contin-uous-wave and quasi-continuous lasers, whenused properly, can also be effective. The lasersinclude the CW argon laser (488 and 514 nm), aCW dye laser (577 and 585 nm), a CW krypton(521–530 nm), a quasi-CW copper vapor laser(510 and 578 nm), an erbium (2,940 nm), andCO2(10,600 nm) laser.The CW and quasi-CW visible light lasers canbe used to selectively remove pigmented lesions.However, because of the shorter wavelengths ofthese lasers, they penetrate only superficially. Thus,they are effective only for epidermal pigmentedlesions. Furthermore, in the absence of reproduc-ible spatial thermal injury confinement, the risk ofscarring and pigmentary changes is significant inthe hands of inexperienced operators.The pigment non-selective erbium and CO2lasers can be used to remove epidermal pigmenteffectively because of the ability to target H2O inthe epidermis. The non-specific thermal damageleads to destruction of the lesion with denudingof the epidermis. Pigment is thus damaged as asecondary event. This destruction is followed byhealing that may have some erythema and possi-ble pigmentary and textural changes.Q-Switched LasersThe fundamental principle behind laser treatmentof cutaneous pigment and tattoos is selectivedestruction of undesired pigment with minimalcollateral damage. This destruction is achievedby the delivery of energy at the absorptive wave-length of the selected chromophore. The expo-sure time must also be limited so that the heatgenerated by the laser–tissue interaction isconfined to the target.The target chromophore of pigmented lesionsis the melanosome and that of tattoos is theinsoluble, submicrometer intracellular pigments.Q-switched lasers produce pulses in the nanosec-ond range. These high peak power lasers deliverlight with a pulse width shorter than the approxi-mately 1-ms thermal relaxation time of the mel-anosomes or the tattoo ink particles. VariousQ-switched lasers (532 nm frequency-doubledQ-switched Nd-YAG laser, 694 nm ruby, 755 nmAlexandrite, 1,064 nm Nd-YAG) are thereforeused for the treatment of various epidermal, der-mal, mixed epidermal and dermal pigmentedlesions and tattoos (Table 3.2).To date, Q-switched lasers have been shown totreat both epidermal and dermal pigmentedlesions effectively in a safe, reproducible fashion.Q-switched lasers used for the treatment ofsuperficial pigmented lesions include the 532 nmfrequency-doubled Q-switched Nd-YAG laser,the 694 nm ruby and the 755 nm alexandritelasers. Strong absorption of light at these wave-lengths by melanin make these lasers an excellenttreatment modality for superficial pigmentedlesions. The Q-switched 694 nm ruby, 755 nmAlexandrite lasers and 1,064 nm Nd-YAG lasersare useful for treating deeper pigmented lesionssuch as nevus of Ota and tattoos. The Q-switched1,064 nm should be used when treating patientswith darker skin, because it reduces the risk ofepidermal injury and pigmentary alteration.Pulsed-Dye LaserThe short wavelength (510 nm) and 300 ns pig-ment lesion dye laser (PLDL) is highly effectivein the treatment of superficial pigmented lesionsand red tattoos, but is no longer commerciallyavailable.Long-Pulsed LasersTo target large, pigmented lesions, such are hairfollicles or nevocellular nevi, lasers with longer(millisecond-range)pulsedurationsaremoresuitable(Table 3.1). These include the long-pulsed 694 nmruby,755nmalexandrite,810nmdiodeand1,064nmNd-YAG lasers. The millisecond pulse width moreclosely matches the thermal relaxation time of thehair follicles or the nested melanocytes. Collateralthermal damage provides an injury to the stem cells
  • 44 Z. Al-Dujaili and C.C. DierickxTable3.1LongpulselasersfortreatmentofpigmentedlesionsLightsourceWavelength(nm)SystemnamePulseduration(ms)Fluence(J/cm2)Spotsize(mm)Repetitionrate(Hz)OtherfeaturesLongpulseruby694E2000(Palomar)3,10010–4010,201Coolinghandpiece0–10ºCFiberdeliveryPhotonrecyclingEpitouchRuby(Sharplan)1.210–403–61.2TriplepulsetechnologyRubyStar(Aesclepion-Meditec)4Upto35Upto141Dualmode:mayalsobeQ-switchedSinon(Wavelight)4Upto305,7,90.5–2ColdairunitMayalsobeQ-switchedLongpulseAlexandrite755Apogee(Cynosure)0.5–30025–505,10,12,153ColdairorintegratedcoolingGentlelase(Candela)310–1006,8,10,12,15,18Upto1.5DynamiccoolingdeviceEpitouchALEX(Sharplan)*2–40Upto505,7,101ScanneroptionUltrawaveII/III(AdeptMedical)5–505–558,10,121–2Availablewith532nmand/or1,064nmNd:YAGEpicare(LightAge)3–30025–407,9,12,151–3Arion(WaveLight)1–50Upto406,8,10,12,14Upto5ColdairunitDiodelaser800LightSheer(Lumenis)5–40010–1009X9,12x12Upto2CoolinghandpieceApex-800(Iridex)5–1005–60(600W)7,9,11Upto4CoolinghandpieceSLP1000™(Palomar)5–1,000Upto575J12Upto3SheerCool™triplecontactcooling,photonrecyclingMedioStar(Aesclepion-Meditec)50Upto6410,12,14Upto4F1DiodeLaser(Opusmed)15–4010–40J5,74
  • 453 Laser Treatment of Pigmented LesionsLong-pulsedNd:YAG1,064CoolGlide(Cutera)0.1–300Upto3003,5,7,10Upto2Contactpre-coolingLyra(Laserscope)20–1005–90010ContactcoolingPhotonrecyclingUltrawaveI/II/III(AdeptMedical)5–1005–5002,4,6,8,10,121–2Availablewith532nmNd:YAGand/or755nmAlexandriteGentleYag(Candela)0.25–300Upto6001.5,3,6,8,10,12,15,18Upto10CryogensprayoptionalVARIA(CoolTouch)300–500Upto5003–10PulsedcryogencoolingwiththermalquenchingAcclaim7000(Cynosure)0.4–3003003,5,7,10,125ColdairorintegratedcoolingSmartepilII(Cynosure)Upto10016–2002.5,4,5,7,106SmartcoolScannerDualis(Fotona)5–200Upto6002–10VasculightElite(Lumenis)2–1670–150J60.33CombinedwithIPLProfile(Sciton)0.1–200Upto400Mydon(WaveLight)5–9010–4501.5,3,5,7,101–10Contactoraircooling
  • 46 Z. Al-Dujaili and C.C. DierickxTable3.2Q-switchedlasersfortreatmentofpigmentedlesionsandtattoosLightsourceWavelength(nm)SystemnamePulseduration(ns)Fluence(J/cm2)Spotsize(mm)Repetitionrate(Hz)OtherfeaturesQ-Switchedruby694Sinon(Wavelight)20Upto153,4,50.5–2Coldairunit(optional)AlsolongpulseSpectrumRD-1200(Palomar)283–10J5,6,50.8RubyStar(Aesclepion-Meditec)30Upto10Upto51Dualmode:mayalsobeQ-switchedQ-SwitchedAlexandrite755Accolade(Cynosure)607–30J2.4,3,5Upto5Ta2Eraser(LightAge)607.5J48–10Alexlazr(Candela)50Upto122,3,4Upto5Q-SwitchedNd:YAG532/1,064Softlight(Thermolase)12–182.5–37Upto10Only1,064nmMedLiteC6(HOYA/ConBio)<20Upto123,4,6,8Upto10532and1,064nmQ-Clear(LightAge)2–122,3,41–6532and1,064nmQ-YAG5™(Palomar)3Upto12.52,4,6Upto10532and1,064nm
  • 473 Laser Treatment of Pigmented LesionsTable3.3IntensepulsedlightsourcestreatmentofpigmentedlesionsLightsourceSystemnameSpectrum(nm)Opticalfilterforpigment(nm)Pulseduration(ms)Pulsedelay(ms)Fluence(J/cm2)Spotsize(mm)SpecialfeaturesIPLEllipseFlex(DDD,Horsholm,Denmark)400–950555–9502×2.5108–1010×48DualmodefilteringtechniqueIPLQuantumSR(Lumenis)560–1,2006–265–6015–458×34IPLProlite(Alderm,Irvine,CA)550–900550–9002210–5010×20FLP(FluorescentPulsedLight20×25IPLPhotoLight(CynosureChelmsford,MA)400–1,200550–1,2005–503–1646×18XenonpulsedlampIPLQuadraQ4(DermaMedUSA)510–1,2004810–2033×15QuadPulsedLightSystemIPLSkinStation(Radiancy,Orangeburg,NY)400–1,200354–735×12LightHeatEnergy(LHE)IPLSpectraPulse(PrimaryTechnology,Tampa,FL)510–1,2003×124and5Resp10–2015×33LightEnergyRecycling(LER)IPL+Nd-YAGVascuLightElite(Lumenis)515–1,2000.5–253–9035×8Contactcooling/combinedwith1,064IPL+Nd-YAGStarLux(Palomar)400–1,200LUX-G:500–670and870–1,200LuxG:0.5–500LuxG:Upto50LuxG:12×12Lux1,064LUX-Y:525–1,200LuxY:1–500LuxY:Upto35LuxY:16×46LuxR:650–1,200LuxR:5–500LuxR:Upto30LuxR:16×46LuxRs:650–1,200LuxRs:5–500LuxRs:Upto50LuxR:12×28IPL+Nd-YAGXeo(Cutera)600–850600–8505–20IPL+BIPOLARRFAuroraSR(YokneamIllit,Syneron)580–980580–980Lightenergy,10–3012×25RFenergy,5–20
  • 48 Z. Al-Dujaili and C.C. Dierickxlocated in the outer rooth sheeth or the melanocytesadjacent to the target area that may actually notcontain melanin. However, it is unlikely that everynevus cell is destroyed. Cautious follow-up of nevitreated with laser light is necessary.Intense Pulsed Light SourcesIntense pulsed light (IPL) systems are high-inten-sity light sources, which emit polychromatic light(Table 3.3). Unlike lasers, these flashlamps workwith non-coherent light over a broad wavelengthspectrum of 515–1,200 nm. Because of the widespectrum of potential combinations of wave-lengths, pulse durations, pulse intervals andfluences, IPLs have proven to very efficiently treatphotodamaged pigmented lesions like solar len-tignes and generalized dyschromia.IndicationsThere are many types of pigmented lesions. Eachvaries in the amount, depth and density of mela-nin or tattoo ink distribution. The approach to thetreatment of cutaneous pigmentation depends onthe location of the pigment (epidermal, dermal ormixed), the way it is packaged (intracellular,extracellular) and the nature of the pigment (mel-anin or tattoo particles). Among the benign pig-mented lesions which do respond well to lasertreatment are lentignes, ephelides (freckles),nevus of Ota, nevus of Ito, and “blue” nevus.Varying results are obtained in café au lait-macu-lae, nevus spilus and nevus of Becker. Treatmentof congenital and acquired nevi is still controver-sial because of the risk of incomplete destructionofdeepersituatednevuscells.Hyperpigmentation,like melasma and post-inflammatory hyperpig-mentation, only shows a moderate response.Finally, laser treatment in itself can result in post-inflammatory hyperpigmentation.Epidermal Pigmented LesionsIn general, epidermal pigment is easier to eradi-cate than dermal pigment because of its proximityto the skin’s surface. Several lasers can effec-tively treat epidermal lesions. These include theQ-switched laser systems, pulsed visible lightlasers and flashlamps, CW lasers and CO2orerbium lasers. The goal is to remove unwantedepidermal pigmentation and as long as the injuryis above the dermal-epidermal junction, it willheal without scarring.Lentigo Simplex, Solar LentigoLentigines are benign macular epidermal lesionscaused by ultraviolet that contain melanin withinkeratinocytes and melanocytes. The superficialnature of lentigines allows the use of severallasers, including, frequency- doubled Q-switchedNd-YAG, Q-switched ruby, alexandrite, Nd-YAG,pulsed 510 nm, CW argon, CO2or erbium andother pulsed visible-light lasers. Labial melano-cytic macules are similar lesions found on themucosal surface and respond well to treatmentwith Q-switched lasers (Fig. 3.2).Lentigines frequently clear with 1–3 treat-ments. The argon laser (488, 514 nm), the 510pigment laser and the 532 nm green light laserstreat lentigines with superior efficacy, especiallylightly pigmented lesions in which less chro-mophore is present. These shorter wavelengthlasers are better absorbed by melanin but haveless penetration.Fractional photothermolysis (FP) has recentlybeen used successfully to treat lentigines andoverall dyschromia. A novel 1,927 nm thuliumfiber laser was introduced as an addition to the1,550 nm erbium-doped fiber laser (Wanner et al.2007). This wavelength has a ten times greaterabsorption coefficient for water, conferringgreater ability to target epidermal processes.Fractional ablative devices have also been used toimprove photodamage (Sherling et al. 2010).Studies have shown greater improvement withmicrofractionl CO2when compared to microfrac-tional Er:YAG.Correct diagnosis is a main concern whentreating lentigines. Lentigo maligna should notbe treated with laser. Although initially one canobtain excellent cosmetic results, recurrences arefrequently seen. Lentigo maligna frequently has
  • 493 Laser Treatment of Pigmented Lesionsan amelanotic portion, which is not susceptible tolaser treatment and will allow for recurrence.These cases emphasize the importance of carefulclinical assessment before any laser surgery andthe need to advise patients to return for evalua-tion if pigmentation does return.Seborrheic KeratosisSeborrheic keratoses are benign epidermal lesionsthat have melanin distribution similar to lentignesand a thickened, hyperkeratotic epidermis. Liquidnitrogen cryotherapy and other surgical methodslike CO2or erbium laser are useful in treating theselesions, but are not practical modalities to toleratein patients who have large numbers of lesions.Using pulsed green or Q-switched lasers offer thepossibility to quickly and efficiently destroy hun-dreds of flat pigment seborrheic keratoses.EphelidesEphelidesorfrecklesareresponsivetoQ-switchedlaser treatment. Patients who tend to freckle arelikely to refreckle with any sun exposure. At afollow-up of 24 months after laser treatment,40 % patients showed partial recurrence.However, all the patients maintained >50 %improvement. The use of a broad band sunscreenis therefore indicated.Café au Lait MaculesCafé au lait macules are light to dark brown flathypermelanotic lesions and may be a solitarybenign finding or associated with certain genoder-matoses (e.g., neurofibromatosis). Histologically,hypermelanosis is present within the epidermisand giant melanosomes may be present in bothbasal melanocytes and keratinocytes. Althoughcafé au lait macules are thin, superficial lesions,they are notoriously difficult to treat and multipletreatments are required for even the possibility ofcomplete eradication. There is probably a cellularinfluence in the dermis that triggers the pigmen-tation in the more superficial cells. This under-lying biology may also explain why pigmentrecurrences are often observed. Lesions mayremain clear for up to a year with spontaneousor UV-induced recurrences in more than 50 % ofcases. Patient education is important so that thepossibility of recurrence is understood. However,given the significant disfigurement associatedwith many of these larger facial lesions, lasertreatment is an excellent treatment option.Q-switched lasers with wavelengths of 532 nmand 694 nm, or the pulsed 510 nm (Alster 1995)laser can adequately treat the café au lait macules(Fig. 3.3). Erbium laser superficial abrasion ofthe epidermis of a “Q-switched laser-resistant”cafe-au-lait macule has also been reported to besuccessful treatment modality.Nevus SpilusWhen darker-pigmented macules or papules(junctional or compound melanocytic nevi) liewithin the café au lait macule, the lesion is callednevus spilus. The lasers used for café au laitmacules have also been used for nevus spilusabFig.3.2 (a) Labial lentigo before treatment. (b) Completeclearance of labial lentigo after single treatment with aQ-switched alexandrite laser
  • 50 Z. Al-Dujaili and C.C. Dierickx(Carpo et al. 1999). The darker lesions tend torespond better than the lighter café au lait mac-ule. There can be complete removal of the junc-tional or compound nevus portion but noimprovement in the cafe-au-lait portion. Cases ofnevus spilus transformation into melanoma havebeen reported in the literature. These casesemphasize the need for careful clinical assess-ment before any laser surgery and continuedevaluation after laser treatment.Dermal–Epidermal Pigmented LesionsBecker’s NevusBecker’s nevus is an uncommon pigmentedhamartomas that develops during adolescenceand occurs primarily in young men. The nevus ischaracterized by hypertrichosis and hyperpig-mentation and is usually located unilaterally overthe shoulder, upper arm, scapula or trunk. Theselesions often require the use of millisecondpigment-specific lasers for treatment of the hair,but the pigment lightening is variable. Test siteswith a variety a pigment-specific Q-switched andmillisecond lasers or flashlamps is recommendedto determine which one (or combination) will bethe best treatment option (Fig. 3.4). More recently,ablation of the epidermis and superficial dermiswith an erbium laser has been shown to result inoccasional complete pigment clearance with asingle treatment.Post-inflammatory HyperpigmentationTreatment of post-inflammatory hyperpig-mentation with laser is unpredictable andoften unsatisfactory. Furthermore, patientswith hyperpigmentation following trauma arelikely to respond to laser irradiation with anexacerbation of their pigment. The use of testsites is therefore recommended before an entirearea is treated.Post-sclerotherapy HyperpigmentationCutaneous pigmentation commonly occurs fol-lowing sclerotherapy of varicose veins.Pigmentation most likely reflects hemosiderindeposition, which is secondary to extravasationof red blood cells through the damaged endothe-lium (Goldman et al. 1987). Hemosiderin has anabsorption spectrum that peaks at 410–415 nmfollowed by a gradually sloping curve throughoutthe remainder of the visible spectrum. SeveralQ-switched or pulsed lasers have therefore beenreported to result in significant resolution ofhemosiderin pigmentation (Sanchez et al. 1981).MelasmaMelasma is an acquired, usually symmetric lightto dark brown facial hypermelanosis. It is associ-ated with multiple etiologic factors (pregnancy,abcFig. 3.3 Café au lait macule. Complete clearing after 4treatments
  • 513 Laser Treatment of Pigmented Lesionsracial, and endocrine) and one of the primarycauses of its exacerbation appears to be exposureto sunlight. Although the results after Q-switchedlaser treatment are usually initially encouraging,repigmentation frequently occurs.Destruction of the abnormal melanocytes witherbium:YAG or CO2laser resurfacing has beenattempted. It effectively improves melasma, how-ever, there is almost universal appearance of tran-sient post-inflammatory hyperpigmentationwhich necessitates prompt and persistent inter-vention. Combination of pulsed CO2laser fol-lowed by Q-switched alexandrite laser (QSAL)treatment to selectively eliminating the dermalmelanin with the alexandrite laser has also beenexamined. Combined pulsed CO2laser and QSALshowed a better result than CO2or QSAL alonebut was associated with more frequent adverseeffects. Long-term follow-up, and a larger num-ber of cases, are required to determine its efficacyand safety for refractory melasma.Nevocellular NeviAlthough laser treatment of many pigmentedlesions is accepted, treatment of nevocellularnevi is an evolving field with much controversy.It has yet to be determined if laser treatmentincreases the risk of malignant transformation byirritating melanocytes or decreases it by decreas-ing the melanocytic load. For this reason, lasertreatment of nevi should be undertakencautiously.Congenital Melanocytic NeviThe management of giant congenital melanocyticnevi (GCMN) remains difficult. It has been wellproved that there is an increased risk of malig-nant changes among patients with these lesions,although the amount of increased risk for eachindividual patient is not clear. There is also a bal-ance to be achieved between limiting the risk ofmalignant change and minimizing the disfiguringappearance of these lesions.Sometimes GCMN are too large to beremoved by multiple surgical excisions or use ofosmotic tissue expanders. Removal of superficialnevus cells is possible by dermabrasion, curet-tage, shave excision or laser. High energy CO2laser therapy is less traumatic and can produceacceptable cosmetic results. Erbium laser treat-ment can also be used because it causes lessthermal damage and faster wound healing.These techniques, although improving the cos-metic appearance, do not remove all nevus cellnests. Therefore they do not completely elimi-nate the risk of malignant transformation.Treatment of giant, congenital nevi with along-pulsed ruby laser has been reported. Thesesystems show promise with follow-up for at least8 years after laser treatment. There has been noevidence of malignant change in the treated areas.However the longer laser emitted pulsewidthscan lead to thermal damage of surrounding col-lagen with resultant scar formation. This is espe-cially true with darker, thicker lesions with a deepdermal component, which are often the oneswhose removal is most desired. Combinationtherapy is therefore under investigation whereQ-switched or resurfacing lasers may be usedfirst to reduce the superficial component, fol-lowed by one of the millisecond pigment specificlasers.Congenital and Acquired SmallMelanocytic NeviThe Q-switched ruby, alexandrite and Nd-YAGlasers have been studied for treatment of mel-anocytic nevi (Goldberg and Stampien 1995).Although clearing rates as high as 80 % havebeen reported, short-pulsed lasers are not recom-mended for nevi, because of the high post lasertreatment recurrence rates.Fig. 3.4 Beckers nevus. Good clearing in testspot withlong-pulsed Alexandrite laser (round spots) and in testspotwith IPL (rectangles)
  • 52 Z. Al-Dujaili and C.C. DierickxMelanocytic nevi often have nested melano-cytes with significant amounts of melanin andtherefore may act more as a larger body than asindividual melanosomes. It has therefore beensuggested that longer pulsed ruby, alexandrite ordiode lasers or Q-switched lasers in combinationwith longer-pulsed lasers may provide a moreeffective treatment with fewer recurrences. Alllaser systems have been partially beneficial. Nolesions have had complete histologic removal ofall nevomelanocytes (Duke et al. 1999).Dermal Pigmented LesionsThe development of Q-switched lasers has revo-lutionized the treatment of dermal melanocy-toses. The dendritic cells found deep in the dermisare particularly sensitive to short pulsed laserlight, frequently resulting in complete lesionalclearing without unwanted textural changes.Nevus of Ota, Nevus of ItoNevus of Ota is a form of dermal melanocytichamartoma that appears as a bluish discolorationin the trigeminal region. Histologic examinationshows long, dermal melanocytes scattered largelythe upper half of the dermis. Nevus of Ito is apersistent grayish blue discoloration with thesame histologic characteristics of nevus of Ota,but is generally present on the shoulder or upperarm, in the area innervated by the posterior supra-clavicular and lateral brachial cutaneous nerves.The dermal melanocytes found within theselesions contain melanin and are highly amenable totreatment with Q-switched ruby (Goldberg andNychay 1992), alexandrite (Alster 1995) orNd-YAG lasers. Four to eight treatment sessionsare typically required to treat these lesions. Possibleside effects like post-inflammatory hyperpigmenta-tion, hypopigmentation or scarring and recurrencesare infrequent. Although there have been no reportson successful treatment of nevus of Ito, treatmentwith Q-switched lasers should be efficacious.Blue NeviBlue nevi are benign melanocytic lesions thatarise spontaneously in children or young adults.The melanocytes are deep within the dermis andthe blue-black color results from the Tyndall lightscatteringeffectoftheoverlyingtissues.Althoughextremely rare, malignant blue nevi have beenreported. Because of their benign nature, bluenevi are usually removed for cosmetic reasons.The deep dermal melanocytes respond well toQ-switched laser treatment, as long as the lesiondoes not extend in the deep subcutaneous tissue.Acquired Bilateral Nevus of Ota-LikeMacules (ABNOMs)Acquired bilateral nevus of Ota-like macules(ABNOM), also called nevus fuscoceruleus zygo-maticus or nevus of Hori, is a common Asiancondition that is characterized by bluish hyperpig-mentation in the bilateral malar regions. Unlikenevus of Ota, ABNOM is an acquired conditionthat often develops after 20 years of age, involvesboth sides of the face, and has no mucosal involve-ment. Histologically, actively melanin synthesiz-ing dermal melanocytes are dispersed in thepapillary and middle portions of the dermis. Sincethese lesions are histologically a form of dermalmelanocytosis like nevus of Ota, melanin-targetinglasers should be effective in the treatment.Although promising results in the treatment ofHori’s nevus with Q-switched ruby CO2withQ-switched ruby alexandrite and Nd-YAG lasershave been reported, the treatment responses havebeen noted to be less effective than that of nevus ofOta. Multiple laser sessions are necessary to obtaincosmetically desired improvement. A higher rateof postinflammatory hyperpigmentation is oftenpresent after laser treatments.TattoosThe popularity of tattoos is burgeoning with20–30 million tattooed individuals in the WesternWorld. Requests for removal can be expected torise concurrently with increased applications.Despite their relatively easy acquisition, theremoval of tattoos has long been a real problem.Laser removal of tattoos is potentially a morecosmetically acceptable method of removing tat-toos than surgical excision or dermabrasion.Tattoo PigmentsTattoos, a form of exogenous pigment, are usu-ally composed of multiple colors and various
  • 533 Laser Treatment of Pigmented Lesionsdyes. In contrast to drugs and cosmetics, tattoopigments have never been controlled or regulatedin any way, and the exact composition of a giventattoo pigment is often kept a “trade secret” bythe manufacturer. In most cases, neither the tattooartist nor the tattooed patients have any idea ofthe composition of the tattoo pigment.Until recently, most coloring agents in tattoopigment were inorganic heavy metal salts andoxides, like aluminum, titanium, cadmium, chro-mium, cobalt, copper, iron, lead, and mercury.There has been a shift in recent years away fromthese agents toward organic pigments, especiallyazo- and polycyclic compounds. These pigmentsare considered safer and well tolerated by theskin, although allergic reactions and phototoxic-ity occur.Laser Removal of TattoosFor Q-switched laser tattoo treatment to be effec-tive, the absorption peak of the pigment mustmatch the wavelength of the laser energy. Similarcolors may contain different pigments, with dif-ferent responses to a given laser wavelength, andnot all pigments absorb the wavelengths of cur-rently available medical lasers.Tattoos absorb maximally in the followingranges: red tattoos, from 505 to 560 nm (greenspectrum); green tattoos, from 630 to 730 nm(red spectrum); and a blue-green tattoo, in tworanges from 400 to 450 nm and from 505 to 560 nm(blue-purple and green spectrums, respectively).Yellow tattoos absorbed maximally from 450 to510 nm (blue-green spectrum), purple tattoos-absorbed maximally from 550 to 640 nm (green-yellow-orange-red spectrum), blue tattoosabsorbed maximally from 620 to 730 nm (redspectrum), and orange tattoos absorbed maxi-mally from 500 to 525 nm (green spectrum).Black and gray absorbed broadly in the visiblespectrum, but these colors most effectively absorb600–800 nm laser irradiation.Three types of lasers are currently used fortattoo removal: Q-switched ruby laser (694 nm),Q-switched Nd:YAG laser (532 nm, 1,064 nm),and Q-switched alexandrite (755 nm) (Adrianand Griffin 2000; Kilmer 2002). The Q-switchedruby and alexandrite lasers are useful for remov-ing black, blue and green pigment (Alster 1995).The Q-switched 532 nm Nd:YAG laser can beused to remove red pigments and the 1,064 nmNd:YAG laser is used for removal of black andblue pigments (Kilmer et al. 1993). Since manywavelengths are needed to treat multicolored tat-toos, not one laser system can be used alone toremove all the available inks (Levine andGeronemus 1995).There is still much to be learned about remov-ing tattoo pigment. Once ink is implanted into thedermis, the particles are found predominantlywithin fibroblasts, macrophages and occasionallyas membrane-bound pigment granules.Exposure to Q-switched lasers produces selec-tive fragmentation of these pigment-containingcells. The pigment particles are reduced in sizeand found extracellularly. A brisk inflammatoryresponse occurs within 24 h. Two weeks later, thelaser altered tattoo ink particles are found repack-aged in the same type of dermal cells.It is not yet clear how the liberated ink parti-cles are cleared from the skin after laser treat-ment. Possible mechanisms for tattoo lighteninginclude: (1) systemic elimination by phagocyto-sis and transport of ink particles by inflammatorycells, (2) external elimination via a scale-crustthat is shed or (3) alteration of the optical proper-ties of the tattoo to make it less apparent. The firstof these appears clinically and histologically tobe the dominant mechanism.There are five types of tattoos: professional,amateur, traumatic, cosmetic and medicinal. Ingeneral, amateur tattoos require less treatmentsessions than professional multi-colored tat-toos. Densely pigmented or decorative profes-sional tattoos are composed of a variety ofcolored pigments and may be particularlydifficult to remove, requiring ten or more treat-ment sessions in some cases (Fig. 3.5). A 100 %clearing rate is not always obtained and, insome instances, tattoos can be resistant to fur-ther treatment. Amateur tattoos are typicallyless dense, and are often made up of carbon-based ink that responds more readily toQ-switched laser treatment (Fig. 3.6). Traumatictattoos usually have minimal pigment depositedsuperficially and often clear with a few treat-ments (Fig. 3.7). Caution should be used whentreating gunpowder or firework tattoos, because
  • 54 Z. Al-Dujaili and C.C. Dierickxthe implanted material has the potential toignite and cause pox-like scars.ConsentAfter obtaining informed consent (Fig. 3.8), thefollowing options are considered.Personal Laser TechniqueThe approach to treatment will vary with the chosenlaser and the whether the pigmented lesion to betreated is epidermal, dermal or mixed. Tattoos mayshow a different response (Tables 3.4, 3.5, and 3.6).Q-Switched Ruby Laser (694 nm)The first Q-switched laser developed was a rubylaser. Current models employ a mirrored articu-lated arm with a variable spotsize of 5 or 6.5 mm,a pulsewidth of 28–40 ns and a maximum fluenceabFig. 3.6 Amateur tattoo. Complete clearing after 2treatmentsFig. 3.5 Professional tattoo. Partial clearing after 4treatmentsab
  • 553 Laser Treatment of Pigmented Lesionsof up to 10 J/cm2. The 694 nm wavelength is mostwell absorbed by melanin. Because hemoglobinabsorbs 694 nm light poorly, ruby laser treatspigmented lesions very efficiently.Most lentigines and ephelides clear after 1–3treatmentswiththeQ-switchedrubylaser(QSRL).Café au lait macules, nevus spilus, Becker’s nevusrespond moderately well. Recurrences are fre-quent with these lesions, especially when incom-plete clearing is obtained. The QSRL has becomethe treatment of choice for dermal pigmentedlesions like nevus of Ota or Ito. The long wave-length, the big spot size and the high deliveredenergy per pulse generates a high fluence deep ina bFig. 3.7 Traumatic tattoo. Clearing after 3 treatmentsIndication Laser Spotsize Fluence (J/cm2)Lentigines 510 nm PLPD 3 2.5QS 532 nm Nd-YAG 4 3QS 694 nm ruby 6.5 3–5QS 755 nm alexandrite 4 3.4Café au lait macules 510 nm PLPD 5 2–3.5QS 532 nm Nd-YAG 3 1–1.5QS 694 nm ruby 6.5 3–4.5QS 755 nm alexandrite 3 4–5Becker’s nevus QS 532 nm Nd-YAG 3 1.5–2QS 694 nm ruby 6.5 4.5QS 755 nm alexandrite 3 6QS 1,064 nm Nd-YAG 3 4–5Nevus Spilus QS 532 nm Nd-YAG 3 1.5–2QS 694 nm ruby 6.5 4.5QS 755 nm alexandrite 3 6QS 1,064 nm Nd-YAG 3 4–5Tattoo 510 nm PLPD 5 2–3.5QS 532 nm Nd-YAG 3 2–3.5QS 694 nm ruby 6.5 5–8QS 755 nm alexandrite 3 6–6.5QS 1,064 nm Nd-YAG 3 5–8Nevus of Ota QS 694 nm ruby 6.5 5–6QS 755 nm alexandrite 3 6.5QS 1,064 nm Nd-YAG 3 5.0Table 3.4 Suggestedtreatment parameters forpigmented lesions
  • 56 Z. Al-Dujaili and C.C. DierickxFig. 3.8 Consent form
  • 573 Laser Treatment of Pigmented Lesionsthe tissue. This all leads to efficient targeting ofdeepmelanocytes.AseffectiveasotherQ-switchedlasers are for removing black tattoo ink, the QSRLis one of the better lasers for removing dark blueor green ink. Removal of red tattoo ink is prob-lematic given that the QSRL is a red light sourceand is not well absorbed by the red ink particles.Yellow ink does not respond to QSRL treatmentbecause the absorption of yellow inks is very lowin this laser’s red to near-infrared spectrum ofdelivered light.Fig. 3.8 (continued)Table 3.5 Most effective Q-switched lasers for differenttattoo ink colorsTattoo ink color LaserBlue/black Q-Switched ruby, Q-Switchedalexandrite, Q-Switched 1,064 nmNd-YAGGreen Q-Switched ruby, Q-SwitchedalexandriteRed/orange/purple Q-Switched frequency-doubled532 nm Nd-YAG laser, 510 nmpigment lesion pulsed dye laser
  • 58 Z. Al-Dujaili and C.C. DierickxWhen selecting the energy level for treatmentwith the QSRL, immediate tissue whitening withno or minimal tissue bleeding should be observed.The required energy level is determined by thedegree of pigmentation or the amount and color ofthe tattoo ink. The 6.5 mm spot is recommendedfor most lesions, with an initial fluence of 3–5 J/cm2. The excellent QSRL melanin absorption fre-quently leads to transient hypopigmentation, thatmay take months to resolve. Rarely (in 1–5 % ofcases) one sees permanent depigmentation.Q-Switched Nd:YAG Laser (532–1,064 nm)The Q-switched Nd:YAG laser (QSNd:YL) emits2 wavelengths, 532 and 1,064 nm, with a pulseduration of 5–10 ns, delivered through a mir-rored, articulated arm. Current models have spotsizes of 2–8 mm and can operate at up to 10 Hz.The long QSNd:YL 1,064 nm wavelength hasthe least absorption by melanin and the deepestpenetration. It is therefore potentially effectivefor both epidermal and dermal pigmented lesions.Use of a frequency-doubling crystal, allows emis-sion of a 532 nm wavelength (green). This wave-length is well absorbed by both melanin andhemoglobin. Because of the superficial penetra-tion, this 532 nm laser is limited to treat epider-mal pigmented lesions.Epidermal lesions such as lentigines or eph-elides treated with the QSNd:YL respond as wellto treatment as they do after QSRL treatment.Café au lait macules, nevus spilus, Becker’s nevusdo not respond as well to QSNd:YL treatment.The Q-switched 1,064 nm laser is highly effectivefor removing deep dermal pigment such as nevusof Ota and Ito. Because this wavelength is lessabsorbed by melanin, higher energy is requiredthan with the QSRL. Newly available Q-switchedNd:YAG lasers which generate high fluences atlarge spotsizes, have optimized treatment results.In an effort to treat tattoos without interference ofmelanin absorption, the 1,064 nm Q- switchedNd-YAG laser was developed. It is most effectivefor treating black ink tattoos, especially in darkerskin types. The 532 nm wavelength is the treat-ment of choice for red tattoo pigment.When treating epidermal pigmented lesionswith the 532 nm wavelength, non-specific vascularinjury will occur, leading to purpura, which takes5–10 days to resolve. Because of the ultrashortpulse duration, the Q-switched Nd-YAG producesthe greatest amount of epidermal debris. This canbe minimized by the use of larger spot sizes.Recent studies have shown that larger spot sizesand lower fluences are as effective in removing tat-toopigmentassmallerspotsizesathigherfluences,and have fewer side effects. Therefore when usingthe 1,064 nm wavelength, treatment should there-fore begin with a 4–8 mm spot size at 3–6 J/cm2.Q-Switched Alexandrite Laser (755 nm)The alexandrite laser has a wavelength of 755nm, a pulse duration of 50–100 ns, a spot size of2–4 mm and is delivered by a fiberoptic arm.Fiberoptic delivery allows a more even beamprofile with fewer hot spots.The wavelength of the Q-switched alexandritelaser (QSAL) is similar enough to that of theTable 3.6 Response of pigmented lesions and tattoos to various lasers and light sourcesPigmented lesions TattoosEpidermal Mixed Dermal Amateur Professional510 nm pigment lesion pulsed dye laser +++ + + ++ +++ (red colors)532 nm Q-switched Nd-YAG laser +++ + + ++ +++ (red colors)694 nm Q-switched ruby laser +++ + +++ +++ +++ (green colors)755 nm Q-switched Alexandrite laser +++ + ++ +++ +++ (green colors)1,064 nm Q-switched Nd-YAG laser ++ + +++ +++ +++Intense pulsed light source +++ + ++++, excellent; ++, good; +, fair
  • 593 Laser Treatment of Pigmented LesionsQSRL to obtain comparable results for the treat-ment of epidermal and dermal pigmented lesions,perhaps with the added advantage of a slightlydeeper penetration. Similar to the QSRL, thislaser is effective at removing black, blue andmost green tattoo inks, and less proficient atremoving red or orange inks.Depending on the spot size, a starting fluenceof 5–6 J/cm2is usually employed. Immediatelyafter treatment, gray-whitening of the skin occurs,followed by erythema and edema. There is alower risk of tissue splatter because of the longerpulse duration and the more even beam profile.There is also a lower risk of transient hypopig-mentation because of slightly less QSAL melaninabsorption as compared to the QSRL.Pulsed Dye Laser (510 nm)The short wavelength of the pulsed dye laser(PDL)makesitoptimalfortreatmentofsuperficialpigmented lesions. Epidermal lesions such aslentigines, ephelides and flat pigmented sebor-rheic keratoses respond extremely well to the 510 nmpulsed dye laser. Its shallow depth of penetrationinto the skin, makes it less than ideal for treatingdermal pigmented lesions. However, like the fre-quency doubled 532 nm Nd-YAG laser, the 510 nmPDL laser effectively removes bright tattoo colorslike red, purple and orange.Continuous Wave (CW) LasersThe CW argon (488 and 514 nm), CW dye (577and 585 nm), CW krypton (521–530 nm), and thepulse train quasi-CW copper vapor lasers (510and 578 nm) all have been used to treat pigmentedlesions. However, when these lasers are used infreehand mode, reproducibility is lacking and thethermal damage is somewhat unpredictable. Therisk of scarring and pigmentary changes is there-fore significant in the hands of inexperiencedoperators. In general, these CW lasers, when usedby skilled operators, are effective in the treatmentof epidermal pigmented lesions.CO2 and Erbium LasersThe CO2and erbium lasers are sources that emitinfrared (IR) light at a wavelength of 10,600 and2,940 nm respectively. These wavelengths arewell absorbed by water. The lasers destroy thesuperficial skin layers non-selectively and can beused to remove superficial epidermal pigment,especially seborrheic keratoses. Superficialerbium laser epidermal abrasion of a “Q-switchedlaser-resistant” cafe-au-lait macule has also beenreported. Theses ablative lasers can also be help-ful in treating resistant tattoos by removing epi-dermis immediately before Q-switched lasertreatment. This will lead to facilitated transepi-dermal tattoo particle elimination.Intense Pulsed Light (IPL) SourcesMelanin pigmentation, as part of photoaging, canbe epidermal or dermal. It often is a combinationof both. In early solar damage, melasma is a regu-lar constituent; often with both dermal and epi-dermal pigment deposition. In later stages ofsolar degeneration the solar lentigo, which ismainly located in the epidermis, is a prominentfeature. Recently, intense pulsed light sources(IPL) have shown to be highly effective in thetreatment of photodamaged pigmented lesionslike solar lentigines, and generalized dyschromia(Fig. 3.9). Unfortunately light spectra, pulseduration, number of pulses as well as deliveredfluence and the use of skin cooling vary consider-ably among the published investigations, makingdirect comparisons of IPL devices quite difficult.Further Treatment PearlsWhen treating pigmented lesions and tattoos, thelaser handpiece should be held perpendicularover the area to be treated. Pulses should be deliv-ered with 0–10 % overlap until the entire lesion istreated.The desired laser tissue interaction producesimmediate whitening of the treated area with
  • 60 Z. Al-Dujaili and C.C. Dierickxminimal or no epidermal damage or pinpointbleeding. It is best to use the largest spot size tominimize epidermal damage. If epidermal debrisis significant, the fluence should be lowered.Higher fluences may be needed with subsequenttreatments when less pigment or tattoo ink parti-cles are still present in the skin.IPL treatment or Q-switched laser treatmentof epidermal pigmented lesions rarely requiresanesthesia. When needed, a topical anestheticcream can be applied 1–2 h before the procedureto reduce the discomfort. For more completeanesthesia, local anesthetic infiltration or regionalnerve block can be used.Treatment parameters are determined by thetype of lesion and the patient’s skin type. As dis-cussed above, the ideal response is immediatewhitening of the skin with little or no epidermaldisruption. If the fluence is too low, the whiteningwill be minimal, whereas if the fluence is tooacbFig. 3.9 Actinic bronzing. Sloughing of pigment 2 days after treatment. Complete clearance 1 month after treatment 1
  • 613 Laser Treatment of Pigmented Lesionshigh, the epidermis is ruptured and bleedingmight occur. Following treatment with a 510 PDLor a QS 532 nm laser, pinpoint bleeding usuallyappears and lasts for 7–10 days. This occursbecause of vessel rupture after haemoglobinabsorption.The whitening of the treated area lasts about15 min and an urticarial reaction appears aroundthe treated area. In the following days, the treatedarea usually becomes darker and develops a crustthat falls of in 7–10 days (Fig. 3.10). The postop-erative care consists of application of a healingointment, and avoidance of sun exposure, in aneffort to reduce the risk of post-inflammatoryhyperpigmentation.Patients with darker skin types should betreated at lower fluences. Their threshold responsewill occur at lower fluences than is seen withpatients with lighter skin types. Treatment of sun-tanned individuals should be avoided because ofthe high risk of laser-induced hypopigmentation.While one to three treatments are sufficient totreat most lentigines, multiple treatments will benecessary for pigmented birthmarks like café aulait macules.Anesthesia is rarely required for dermal pig-mented lesions. When treating larger areas topi-cal or intralesional anesthesia may be necessary.When treating nevus of Ota, regional nerve blocksusually provide adequate anesthesia.Treatment parameters are again determined bythe type of lesion and the patient’s skin type. Ingeneral, higher fluences are necessary than thoserequired for the treatment of epidermal lesions. Thethreshold response should be immediate whiteningof the skin with little or no epidermal disruption.The same postoperative aftercare and precautionsapply as for epidermal pigmented lesions. Dermalmelanocytoses require multiple treatment sessions,usually performed at 6 weeks intervals or longer.Lesions as nevus of Ota continue to lighten for sev-eral months after each treatment.Anesthesia is usually not required for smalltattoos. For certain individuals or for larger tat-toos, topical or intralesional anesthesia might benecessary.If adequate fluences are available, it is best touse the largest laser spot size. This will reducebackward scattering and therefore minimize epi-dermal rupture. Following treatment, wound careis required to help healing and prevent infection.An antibiotic ointment should be applied. Adressing should be worn for several days untilhealing has been completed.Tattoo treatment usually requires multiple treat-ments to obtain adequate clearing. Amateur tattoosrespond more quickly than do multi-colored pro-fessional tattoos. Complete clearing of tattoos isnot always possible. During the initial consulta-tion, the patient should be informed about this.However, dramatic lightening can be expected.Cosmetic tattoos should be approached withcaution. When treating tattoos with colors thatmay darken (white, light pink, tan or some browncolors), a single test spot should be placed toassess immediate darkening (Figs. 3.11 and 3.12).If darkening occurs, the same test site should beretreated to be sure the ink can be lightenedbefore proceeding further. Although the darkenedpigment may clear easily, it can sometimes bevery recalcitrant to treatment. In this case, CO2orerbium vaporization can be used, as an adjunctivetreatment modality, by removing the epidermisimmediately before Q-switched laser treatmentand/or by facilitating transepidermal tattoo particleelimination.Treatment sessions are performed at intervalof 6 weeks or greater. Waiting longer betweentreatment sessions might be even more beneficialas tattoos may continue to clear for severalmonths following each treatment.Fig. 3.10 Crusting 1 week after laser treatment of tattoo
  • 62 Z. Al-Dujaili and C.C. DierickxComplicationsUnlike previous treatment modalities for pig-mented lesions, Q-switched lasers induce mini-mal side effects. These include pigmentarychanges, partial removal, infection, bleeding, tex-tural changes and tattoo ink darkening.Pigmentary changes following laser treat-ment of pigmented lesions are not uncommon.Transient hypopigmentation is most commonafter treatment with the 694 or 755 nm wave-lengths because absorption by melanin is sostrong. Permanent hypopigmentation can beseen with repetitive treatment sessions, particu-larly at higher fluences. The 1,064 nm wave-length is the least injurious to melanocytes andis therefore the treatment of choice for dark-skinned individuals undergoing laser tattootreatment. Transient hyperpigmentation, whichhas been reported in up to 15 % of cases is morecommon in darker skin types or following sunexposure (Kilmer et al. 1993). The incidence ofscarring is less than 5 %. It is associated withthe use of excessive fluences. It is also morecommon when certain areas like the chest andankle are treated. This complication has alsobeen observed in areas with dense deposition ofink, such as in double tattoos. Larger laser spotsizes tend to minimize epidermal damage andare associated with fewer textural changes.Pigment darkening of cosmetic skin color tat-toos can occur after exposure to any Q-switchedlaser. The darkening occurs immediately and ismost often seen with the red, white or flesh-tonedink colors that are frequently used in cosmetictattoos. These colors often contain ferric oxideand titanium dioxide that can change to a blue-black color after Q-switched laser treatment. Themechanism probably involves, at least for sometattoos, reduction of ferric oxide (Fe2O3, “rust”)to ferrous oxide (FeO, jet black). Recently,Fig. 3.12 Color shift to green after laser test withQ-switched Alexandrite laseracbFig. 3.11 Cosmetic tattoo. Darkening of pigment afterfirst treatment. Partial clearing after 6 treatments withQ-switched Alexandrite laser
  • 633 Laser Treatment of Pigmented Lesionsmultiple color changes following laser therapy ofcosmetic tattoos has been reported (Fig. 3.11).Performing small test areas before completetreatment and using several laser wavelengthsthroughout the course of therapy are essential tothe successful treatment of cosmetic tattoos.Localized allergic reactions can occur withalmost any treated tattoo color (Ashinoff et al.1995). It can result in an immediate hypersensitiv-ity reaction such as urticaria. In the alternative adelayedhypersensitivityreactionsuchasgranulomaformation may occur. The most serious complica-tion reported after Q-switched laser tattoo removalwas a systemic allergic reaction. The Q-switchedtarget intracellular tattoo pigment, causing rapidthermal expansion that fragments pigment-contain-ing cells and causes the pigment to become extra-cellular. This extracellular pigment may then berecognized by the immune system as foreign, poten-tially triggering an allergic reaction. Therefore, if apatient exhibits a local immediate hypersensitivityreaction, prophylaxis before subsequent laser treat-ments with systemic antihistamines and steroidsshould be considered Pulsed CO2and erbium lasersdo not seem to trigger this reaction, since the parti-cle size does not change. These lasers may be usedto enhance transepidermal elimination of ink.Future DevelopmentsNon-invasive, real-time optical diagnostic tools(like Optical Coherence Tomography, confocalmicroscopy, multispectral digital imaging, polar-ized multispectral imaging) are being studied fortheir role in the accurate pre-laser diagnosis ofpigmented lesions as well as a tool for determin-ing efficacy and safety following treatment.Current tattoo laser research is focused onnewer picosecond lasers. The systems may bemore successful than the Q-switched lasers inthe removal of tattoo inks. Such lasers, becausethey emit picosecond pulse widths cause optimalphotomechanical disruption of the tattoo ink par-ticles. Another tattoo approach would the devel-opment of laser-responsive inks. In this casetattoo removal might be feasible with only oneor two treatment sessions.It is also possible that a laser that emits trainsof low-fluence, submicrosecond pulses mightcause even more selective injury to pigmentedcells by limiting mechanical damage modes. Theuse of pulse trains, specifically designed to selec-tively affect pigmented cells in skin, has not yetbeen tested.Since the clearing of tattoo pigment followinglaser surgery is influenced by the presence ofmacrophages at the site of treatment, it has alsobeen suggested that the adjuvant use of cytokineslike macrophage colony-stimulating factor otherchemotactic factors such as topical leucotrienesor the use of a topical immunomodulators likeimiquimod might recruit additional macrophagesto the treatment site. This could expedite theremoval of tattoo pigment following lasersurgery.The extraction of magnetite ink tattoos bya magnetic field has been investigated afterQ-switched laser treatment. When epidermalinjury was present, a magnetic field, appliedimmediately after Q-switched ruby laser treat-ment, did extract some ink. Magnetically-extractable tattoos may therefore become feasibleone day. Delivery of intradermally focused smallenergy nanosecond laser pulses might becomeanother approach for more efficient and safertattoo removal. Finally optical clearing of skinwith hyperosmotic chemical agents is currentlyunder investigation. This approach reduces opti-cal scattering in the skin, thereby enhancingthe effective light dose that reaches the tattooparticles.In 2009, a new tattoo ink was made availablein the United States. Infinitink (Freedom Inc.,Cherry Hill, NJ), created to be easily removedusing laser treatment, uses bioresorbable dyesencapsulated in polymethylmethacrylate beads(Choudhary et al. 2010). These beads also con-tain additional pigments specially designed toallow targeting by specific laser wavelengths.Tattoos created with Infinitink can be removed infar fewer laser treatments than those with tradi-tional pigments. It is the hope that the adoption ofthese types of pigments by the tattoo industry andconsumers will make owning, and if desiredremoving, a tattoo safer.
  • 64 Z. Al-Dujaili and C.C. DierickxQS laser treatment may effectively removevarious kinds of unwanted tattoos. The laser sur-geon must be educated in the nuances of laser tat-too removal to ensure safe and effective treatment.Tattoo removal was revolutionized with theinvention of the laser, and the continuedrefinement of this technology has led to betterand more-predictable outcomes, but furtherresearch is needed regarding the safety of tattoopigments and the breakdown products formedwith exposure to laser light. Current investigationin the field is focused on faster lasers and more-efficient targeting of tattoo pigment particles. Inthe future, these new technologies will offer saferand more-effective laser tattoo removal.Further ReadingsAdrian RM, Griffin L (2000) Laser tattoo removal. ClinPlast Surg 27(2):181–192Alster TS (1995) Q-switched alexandrite laser treatment(755 nm) of professional and amateur tattoos. J AmAcad Dermatol 33(1):69–73Alster TS (1996) Comparison of two high-energy, pulsedcarbon dioxide lasers in the treatment of periorbitalrhytides. Dermatol Surg 22(6):541–545Alster TS, Williams CM (1995) Cafe-au-lait macule intype V skin: successful treatment with a 510 nm pulseddye laser. J Am Acad Dermatol 33(6):1042–1043Anderson R, Parrish J (1983) Selective photothermolysis:precise microsurgery by selective absorption of pulsedradiation. Science 220:524–526Ashinoff R et al (1995) Allergic reactions to tattoo pigmentafter laser treatment. Dermatol Surg 21(4):291–294Carpo BG et al (1999) Laser treatment of pigmented lesionsin children. Semin Cutan Med Surg 18(3):233–243Choudhary S et al (2010) Lasers for tattoo removal: areview. Lasers Med Sci 25(5):619–627Duke D et al (1999) Treatment of benign and atypical neviwith the normal-mode ruby laser and the Q-switchedruby laser: clinical improvement but failure to com-pletely eliminate nevomelanocytes. Arch Dermatol135(3):290–296Geronemus RG (1992) Q-switched ruby laser therapy ofnevus of Ota. Arch Dermatol 128(12):1618–1622GoldbergDJ,NychayS(1992)Q-switchedrubylasertreatmentof nevus of Ota. J Dermatol Surg Oncol 18(9):817–821Goldberg DJ, Stampien T (1995) Q-switched ruby laser treat-ment of congenital nevi. Arch Dermatol 131(5):621–623Goldman MP et al (1987) Postsclerotherapy hyperpig-mentation: a histologic evaluation. J Dermatol SurgOncol 13(5):547–550Kilmer SL (2002) Laser eradication of pigmented lesionsand tattoos. Dermatol Clin 20(1):37–53Kilmer SL et al (1993) Hazards of Q-switched lasers.Lasers Surg Med S5:56Levine VJ, Geronemus RG (1995) Tattoo removal withthe Q-switched ruby laser and the Q-switched Nd:YAGlaser: a comparative study. Cutis 55(5):291–296Ross V et al (1998) Comparison of responses of tattoos topicosecond and nanosecons Q-switched neodymium:YAG lasers. Arch Dermatol 134(2):167–171Sanchez NP et al (1981) Melasma: a clinical, light micro-scopic, ultrastructural, and immunofluorescence study.J Am Acad Dermatol 4(6):698–710Sherling M et al (2010) Consensus recommendations onthe use of an erbium-doped 1,550-nm fractionatedlaser and its applications in dermatologic laser surgery.Dermatol Surg 36:461–469Vano-Galvan S et al (2009) Treatment of light-colouredsolar lentigines with cryotherapy plus alexandritelaser. J Eur Acad Dermatol Venereol 23:850–852Wanner M et al (2007) Fractional photothermolysis: treat-ment of facial and nonfacial cutaneous photodamagewith a 1,550-nm erbium-doped fiber laser. DermatolSurg 33:23–28