', Laser Treatment of Hypertrophic Scars, Keloids, and Striae · SCARS, KELOIDS AND STRIAE Hypertrophic scars appear clinically aserythem-atous, raised, firm areas of fibrotic skin

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Laser Treatment of HypertrophicScars, Keloids, and StriaeTina S. Alster, MD, and Christiane Handrick, MD

The successful use of the 585-nm pulsed dye laserfor the treatment of hypertrophic scars has beenwell established over the past decade. Although 5years ago this treatment option might have beenconsidered as a viable choice only affer all othermethods failed, it is now generally recognized asan excellent first-line treatment option. Early scartreatment with pulsed dye laser irradiation effec-tively prevents scar formation or worsening andyields a better and more prolonged clinical im-provement. The concomitant use of corti coste-roids, 5-fluorouracil, or other treatments is provingto be of particular importance in reducing scarbulk and symptoms of more proliferative scars.Although optimal management for keloids andstriae has yet to be determined, pulsed dye laserirradiation will no doubt continue to playa role intheir treatment.Copyright © 2000 by W.B. Saunders Company

CUTANEOUS DERMAL INJURY eventuatesin the inevitable formation of a scar, which

may be cosmetically acceptable or unacceptable.The reparative process involves inflammation,granulation tissue formation, and matrix remod-eling resulting in a variable degree.of fibrosis. 1,2 Insome cases, exuberant fibrosis may produce dis-figuring hypertrophic scars or keloids. In contrast,endogenous factors, including mechanical skinstretching and hormonal influences, may lead todermal dehiscence resulting in striae distensae or"stretch marks."

Hypertrophic scars, keloids, and striae havebeen notoriously difficult to eradicate with tradi-tional treatments, including surgical excision,corticosteroids, and continuous wave laser de-struction, yielding either unsatisfactory results orhigh lesional recurrence rates3-25 Over the pastdecade, advances in pulsed laser technology haveenabled successful treatment of these lesions, giv-ing millions of patients a new therapeutic option.The experimental use of the 585-nm pulsed dyelaser for hypertrophic scars within port-winestains in the late 1980s initiated a cascade of stud-ies with this vascular-specific laser to improve thetextural quality and appearance of scars.26-32 Inaddition to destruction of its microvascular target,

leading to decreased scar erythema, 585-nmpulsed dye laser irradiation has been shown tofavorably affect scar pliability, hypertrophy, andsymptoms of patient discomfort.26,28,32 Followingan initial observation of pulsed dye laser improve-ment of argon laser-induced scars, Alster and col-leagues26-28,32 have reported similar improve-ments in surgical, traumatic, acne, and burn scars.Subsequent publications by Goldman and Fitz-patrick29,33 have corroborated these findings. Re-search by McCraw and colleagues>' promotedearly postoperative initiation of pulsed dye lasertreatment in order to prevent scar formation orworsening in scar-prone individuals and bodylocations. Reiken and his colleagues= then defin-itively determined the superiority of the 585-nnmwavelength in reducing hypertrophic scar growth(Fig 1). Similarly, the 585-nm pulsed dye laserhas proved useful in the treatment of striae disten-sae (Fig 2).36 Factors determining patient selec-tion, choice oflaser parameters, specific treatmentprotocols, and management of possible adverseeffects to optimize laser treatment of hypertrophicscars, keloids, and striae are reviewed in thisarticle.

CHARACTERISTICS OF HYPERTROPHICSCARS, KELOIDS AND STRIAE

Hypertrophic scars appear clinically as erythem-atous, raised, firm areas of fibrotic skin typicallylimited to the site of the original wound or trauma.They usually form within the first month after theinciting cutaneous injury, often becoming flatterand more pliable over time.

Keloids are even firmer, reddish-purple nodulesthat extend in a claw-like manner beyond the con-fines of the original (sometimes only slight)

From the Washington Institute of Derma to logic Laser Surgery,Washington, DC.Address reprint requests to Tina S. Alster, MD, 2311 M Street,

NW, Suite 200, Washington, DC 20037.Copyright © 2000 by W.B. Saunders Company1085-562910011904-0009$10.0010doi:10.1 053Isder.2000.18369

Seminars in Cutaneous Medicine and Surgery, Vol 19, No 4 (December), 2000: pp 287-292 287

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288 ALSTERAND HANDRICK

wound. Their development starts weeks to yearsafter trauma (although they can arise spontane-ously) and may continue to worsen for decades ine~treme cases.

Both hypertrophic scars and keloids tend to bepruritic or painful on palpation and can be cos-metically unsightly. They may be a consequenceof traumatic injury (eg, laceration, burn, abra-

sion); intentional surgical procedure (eg, exci-sion, electrocautery, cryotherapy, laser surgery);or of vaccination or cystic acne. Their prevalenceranges from 4.5% to 16% of the population.F Sitesof predilection include slow-healing areas (eg, an-terior chest) and movement- and pressure-depen-dent regions (eg, scapula, shoulders, ear lobes).They occur more often in individuals with darker

Fig 1. Hypertrophic laceration scars on the cheek (A) before and (B) 2 monthsafter second pulsed-clyelaser treatment with average fluence of 5.0 J/cm2 (lD-mm spot).

Fig 2. Striae (A) before and (B) 6 weeks after second 585·nm pulsed-clye laser treatment at averagefluence of 3.0 J/cm2 (10·mm spot).

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HYPERTROPHIC SCARS, KELOIDS, AND STRIAE 289

skin tones and patients with impaired collagensynthesis (eg, Ehlers-Danlos syndrome). Othercontributing factors to the development of hyper-trophic scars and keloids include surgery per-formed during pubertal growth spurts, post-trau-matic traction and tension, secondary infection,and foreign body irritation (eg, granulomatous re-sponse to suture material). Scar formation is acomplex multistep process that is not yet fullyunderstood, so no single cell type or factor can bemade responsible for the excessive fibrosis ob-served. The histopathologic appearance of hyper-trophic scars is characterized by whorls of youngfibrous tissue and fibroblasts in a haphazard ar-rangement. Keloids additionally display thick, eo-sinophilic, acellular bands of collagen on micro-scopic examination." The microvessels in bothlesions are often occluded by an excess of endo-thelial cells.v' Although keloids produce high lev-els of hyaluronidase, low concentrations of colla-genase are typical for hypertrophic scars.>?5triae are linear bands of atrophic and wrinkled

skin which occur after excessive dermal stretch-ing andJor under the influence of estrogens andcorticosteroids.w+t They become manifest afterpubertal growth spurts, pregnancy, rapid weightgain, and long-term internal or external cortico-steroid use. In rare cases, they may also occur afterinfections with typhus, para typhus, influenza, ortuberculosis. They often exhibit scar-like features,with early striae appearing erythematous and latestriae showing hypopigmentation and fibrosis.Striae are caused by connective tissue alterationfollowing elastolysis with initial mast cell degran-ulation and macrophage degradation. Histologi-cally, they are characterized by the presence ofdysmorphic elastic fibers and reduced collagenfibers in the dermis.t> The prophylactic or thera-peutic use of topical agents, such as retinoic acid,has shown limited ability to change the structureand appearance of these lesions+t-t>

LASER-INDUCED EFFECTS ONHYPERTROPHIC SCARS, KELOIDS,

AND STRIAE

The positive effects of 585-nm pulsed dye lasertreatment on the appearance and symptomatologyof scars have been evaluated by skin surface tex-tural analyses, erythema reflectance spectrometryreadings, scar height measurements, clinical im-provement, and pliability scores. Histopathologic

examination of scars after laser irradiation revealsimprovement in dermal collagen with finer, morefibrillar, and looser arrangement of collagen fi-bers.28,32 The pulsed dye laser induces selectivevascular thermal injury, leading to thrombosis,vasculitis, and gradual local repair with neovascu-larization.w+" Irradiated scars have also beenshown to exhibit a large number of regional mastcells, which may elaborate a number of cytokinesthat could potentially stimulate the process of col-lagen remodeling.w>? It is also possible that col-lagen synthesis can be stimulated by dermal heatconduction from the laser-irradiated blood ves-sels. An additional mechanism of laser action mayinclude selected microvascular destruction pro-ducing local tissue ischemia and the release ofcollagenase, leading to collagenolysis.>?

LASER TREATMENT PROTOCOL

Patient Selection

Individuals with lighter skin tones (phototypesI and II) are the best treatment candidates becauselittle epidermal melanin is present to serve as acompeting chromophore for pulsed dye laser ab-sorption. Patients with darker skin types can un-dergo pulsed dye laser treatment as well, but flu-ences typically need to be lowered and patientswarned of the possibility of postoperative dyspig-mentation. All body areas affected by keloids andscars appear to be amenable to pulsed dye lasertreatment. A history carefully obtained beforetreatment is important because the mechanism ofthe injury, scar duration, and prior treatment at-tempts may influence treatment parameters. Pre-vious electrocauterization, cryotherapy, and sur-gical excision typically produce increased tissuefibrosis, necessitating the use of higher fluencesandJor a greater number of laser sessions.t? Pa-tients who are on anticoagulant or antiplateletmedications (eg, coumadin, aspirin) should dis-continue their use before laser treatment in orderto reduce the intensity and duration of postoper-ative purpura. Preoperative and follow-up photosare an effective way to document and controltreatment progression.

Intraoperative Considerations

The laser procedure is usually performed in anoutpatient setting because general anesthesia istypically unnecessary. Sufficient local anesthesia

290 ALSTERAND HANDRICK

can be achieved by the application of a topicallidocaine cream (eg, EMLA, Ela-Max) under oc-clusion for 15 to 30 minutes preoperatively. Forthe treatment of scars in more sensitive body ar-eas, intralesionallidocaine injections anclJor nerveblocks can be used. Most patients, however, re-quire no anesthesia whatsoever. Immediately be-fore laser treatment, any anesthetic cream andmake-up should be completely removed. Hair-bearing areas within the treatment area should beprotected with wet gauze. Operative personnel,patients, and accompanying persons should weareye protection (eg, goggles) appropriate to the585-nm wavelength being used. Flammable pre-paratory substances (eg, alcohol, acetone) mustnot be applied on cutaneous surfaces to be treatedbecause of their incendiary potential.

Laser Parameters

Appropriate energy fluences for hypertrophicscars and keloids range from 6.0 to 7.5 j/cm" withthe-use of a 5- or 7-mm spot size, and 4.5 to 5.5j/crrr' with the use of a lO-mm spot. For the treat-ment of striae, a fluence of 3.0 j/cm ' with a 5-, 7-,or lO-mm spot is sufficient. Single laser pulses aredelivered in an adjacent, nonoverlapping mannerto cover the entire scar or stretch mark (Table 1).

Postoperative Management

Purpura and mild swelling are observed afterlaser irradiation of scars, whereas little, if any,tissue hyperemia is seen after stria treatment. Thepurpura-associated color changes and swellingare at their most intense within the first 24 to 48hours, and resolve over 7 to 10 days. The severityof these adverse effects can be limited by the ap-plication of ice packs during the first few hoursafter surgery. The postoperative wound care regi-men involves daily gentle cleansing with mildsoap and water, followed by application of a heal-ing or antibiotic ointment and a nonstick bandage.

If necessary, and once all residual hemosiderinpigmentation has disappeared and dermal healingis complete (typically 6 to 8 weeks), further lasertreatment can be undertaken. The energy fluencecan be adjusted to optimize clinical results de-pending on the tissue response to the precedingtreatment session. If the previous treatmentyielded noticeable scar or stria improvement, thesame fluence should be used again. In instances inwhich only minimal or no improvement is ob-served, the energy should be increased by 0.5Jlcm2

ADVERSE EFFECTS

The most common adverse effect of 585-nmpulsed dye laser treatment is transient hyperpig-mentation, which occurs most often in darker pig-mented individuals and in patients who did notfollow strict precautions against sun exposure.Hyperpigmentation is rarely, if ever, permanent,and the process of fading can be enhanced byapplication of topical bleaching agents (eg, hydro-quinone or arbutin-containing compounds). Fur-ther laser treatment sessions should be delayeduntil all dyspigmentation has completely re-solved. Prolonged erythema, vesiculation, anclJorpruritus of the treatment area should raise con-cerns of contact dermatitis, usually to a topicalantibiotic. Other possible adverse reactions, in-cluding blister formation followed by secondaryinfection or scar worsening, can be prevented bythe use of appropriate laser parameters and avoid-ance of pulse overlap.

RESULTS

The majority of patients with hypertrophicscars will experience up to 80% clinical improve-ment after 2 pulsed dye laser treatments. Morefibrotic or proliferative hypertrophic scars and ke-loids typically require additional treatment ses-sions in order to obtain the desired degree of im- .~

Preoperative Considerations

Table 1. Pulsed-Dye Laser Treatment Considerations and ProtocolPostoperotive ConsiderationsIntraoperotive Considerations

• Topical or no anesthesia usually necessary• Energy densities4.5-5.5 J/cm2 (10-mm spot)6.0-7.0 J/cm2 (7-mm spot)6.5-7.5 J/cm2 (5-mm spot)

• Deliver adjacent, nonoverlapping spots

• Skin types I-III best• HypertrophiC scars are more amenable

• Treatment of all body locations possible• No anticoagulant or anti platelet agent use

• Evaluation for retreatment at 6-8 weeks• Consider bleaching for post-rx hyperpigmentation

• Topical antibiotic ointment• Sunscreen or sun avoidance

>1HYPERTROPHIC SCARS, KELOIDS, AND STRIAE 291

Table 2. Clinical Responses of Scars and Striaeto Laser Therapy

Scar Type Laser Used No. of Treatments Required

HypertrophicKeloidStriae

585-nm pulsed dye585-nm pulsed dye585-nm pulsed dye

2-42-6

1-2

provement (Table 2). The scar qualities that showmost change after pulsed dye laser irradiation in-clude scar color, height, pliability, and texture(Fig 1).26-28.32 Scar-associated erythema fadeseventually, leaving a closer approximation of nat-ural skin tone. Clinical observation and opticalprofilometry have documented diminished scarbulk with a reduction in scar height and texturalimprovement. Many patients appreciate the cessa-tion of scar-related symptoms such as pruritusand burning. The high vascular specificity of thepulsed dye laser is no doubt responsible for thedecreased scar erythema seen, but the nonvascu-lar improvements may best be explained by laser-induced tissue hypoxia stimulating new collagenformation ancl/or controlled collagen heating,

with release or stimulation of various immunofac-tors, resulting in enhanced collagen remodeling.Prolonged follow-up of patients 6 months to sev-eral years after pulsed dye laser treatment has re-vealed no scar worsening nor recurrences, furtherindicating the importance of this therapeutic mo-dality.

ANCILLARY PROCEDURES

Proliferative ancl/or symptomatic hypertrophicscars have been observed to respond even morefavorably to concomitant use of intralesional5-fluorouracil or triamcinolone, with significantreduction in scar height and pruritus and in-creased clinical improvement as compared to thepulsed dye laser alone.5o.51 Hypertrophic scarsthat are hypopigmented and minimally erythem-atous also appear to do better with CO2 laser de-epithelialization, followed by pulsed dye laser ir-radianon.>' whereas keloid scars may respondbest to surgical excision followed by 585-nm lasertreatment in order to reduce the risk of recurrencefrom excessive heat energy."?

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19. Apfelberg DB, Maser MR, Lash H, et al: Preliminaryresults of argon and carbon dioxide laser treatment of keloidscars. Lasers Surg Med 4:283-290, 1984

20. Abergel RP, Dwyer RM, Meeker CA, et al: Laser treat-ment of keloids: A clinical trial and an in vitro study withNd:YAG laser. Lasers Surg Med 4:291-295, 1984

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23. Sherman R, Rosenfeld H: Experience with the Nd:YAG

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