Striae_Distensae

Treatment of Striae Distensae with Fractional Photothermolysis

HANA BAK, MD, BEOM JOON KIM, MD,y WOO JIN LEE, MD, JANG SEOK BANG, MD,z

SUN YOUNG LEE, MD,y JEE HO CHOI, MD, AND SUNG EUN CHANG, MD

BACKGROUND Striae distensae are dermal scars characterized by flattening and atrophy of the epi-dermis. Although many treatment modalities have been tried with variable results, most have beendisappointing.

OBJECTIVE To determine whether striae distensae might respond to fractional photothermolysis.

METHODS Twenty-two women with striae distensae were treated with two sessions each of fractionalphotothermolysis at a pulse energy of 30mJ, a density level of 6, and eight passes at intervals of 4weeks. Response to treatment was assessed by comparing pre- and post-treatment clinical photographyand skin biopsy samples.

RESULTS Six of the 22 patients (27%) showed good to excellent clinical improvement from base-line, whereas the other 16 (63%) showed various degrees of improvement. Most of the lesions withexcellent results were white in color and of long duration. Skin biopsy revealed that average epidermalthickness and dermal thickness were greater than at baseline. The immunoreactivity of procollagentype 1 increased after treatment. There were no significant side effects except erythema and mild pig-mentation.

CONCLUSION Fractional photothermolysis may be effective in treating striae distensae, without sig-nificant side effects. Treatment outcomes were better in patients with white rather than red striae.

The authors have indicated no significant interests with commercial supporters.

Striae distensae, a common skin condition, do notcause any significant medical problems, but theycan be of significant distress to those affected. Striae

are commonly observed in association with preg-

nancy, obesity, growth during adolescence, increased

adrenocortical function, and corticosteroid therapy.

Striae initially appear as pink to purple atrophic

bands sometimes associated with mild pruritus.1

Their exact cause is unknown, although a combi-

nation of hormonal factors associated with lateral

stretch due to increased size of the various portions

of the body is thought to be important. It mainly

occurs on the abdomen and buttocks and sometimes

breasts. Histopathologically, they are characterized

by thinning of the overlying epidermis, with fine

dermal collagen bundles arranged in straight parallel

lines.2 In their early stages, inflammatory changes

are conspicuous, with elastolysis accompanied by

mast cell degranulation, followed by activated mac-

rophages that envelop fragmented elastic fibers.3 In

later stages, the dermal collagen is layered in thin

eosinophilic bundles oriented in straight lines.4

Many treatment modalities have been tried, includ-

ing topical application of tretinoin, pulsed dye laser,

and intense pulsed light, with variable results.57

Although fractional photothermolysis can be used to

treat facial rhytides, acne scars, surgical scars,

melasma, and photodamaged skin, to our knowl-

edge, there have been only a few reports of fractional

photothermolysis for the treatment of striae

distensae.810 The objective of this study was to

evaluate the safety and efficacy of fractional photo-

thermolysis in the treatment of striae distensae.

& 2009 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc. ISSN: 1076-0512 Dermatol Surg 2009;35:12151220 DOI: 10.1111/j.1524-4725.2009.01221.x

1215

Department of Dermatology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea;yDepartment of Dermatology, College of Medicine, Chung-Ang University, Seoul, Korea; zMeline Dermatology Clinic,Seoul, Korea; yGowoonsesang Dermatology Clinic, Seoul, Korea

Methods

Twenty-two Asian women (aged 3246; mean age

36) clinically diagnosed with striae distensae and not

previously treated using any medical or surgical

methods were enrolled. The duration of striae

ranged from 1 to 16 years (average 6 years).

Childbirth caused striae in 18 patients and weight

gain in five. All patients provided written informed

consent, and the local ethics committee approved

the study protocol.

Each patient underwent two laser treatments, at

4-week intervals. Treatment sites included the

abdomen in 15 subjects, the arms in two, the but-

tocks in 10, the back in five, and the thighs in five.

One hour before each treatment, patients were

anesthetized with topical 30% lidocaine gel. A blue

dye (FD&C No. 1) was used to demarcate the areas

of laser treatment, serving as a guide marker for the

intelligent optical tracking device of the laser

handpiece. Each treatment session consisted of a

pulse energy of 30mJ, a density level of 6, and eight

passes. Patients were instructed to avoid the use of

any therapeutic agents during the course of treat-

ment. Treatment responses were assessed by com-

paring pre- and 4-week post-treatment clinical

photography and skin biopsy.

Skin biopsy samples were taken from the most

atrophic site before treatment and 1 month after the

second laser treatment. The excised skin was fixed in

10% formalin and embedded in paraffin. Three-

micrometer-thick sections were stained with

hematoxylin and eosin (H&E), Masson-trichrome,

and Elastica von Gieson stains. Two dermatologists

masked to time of sampling evaluated the

histopathologic results.

Samples from two patients were stained with anti-

bodies to procollagen 1, elastin, and matrix metal-

loproteinase (MMP)-1, followed by incubation with

fluorescein isothiocyanateconjugated secondary

antibody (Sigma, St. Louis, MO). Samples were

viewed under an Olympus BX 50 fluorescence

microscope (Olympus, Tokyo, Japan) equipped for

epifluorescence using appropriate filters. Selected

images were further analyzed through a Leica TCS-

SP-2 laser scanning confocal microscope (LSCM)

(Leica Microsystems, Heidelberg, Germany).

Epidermal and dermal thicknesses of biopsy speci-

mens were measured using an optic micrometer, and

results were compared in individual patients and as

an average. Statistical analysis used the Excel one-

tailed t-test for small paired samples.

Clinical photographs were taken at each visit. No

severe side effects were recorded. Two nontreating

blinded dermatologists analyzed improvements, as

determined photographically, using a quartile grad-

ing scale of 1 (o25%, mild), 2 (2550%, moderate),3 (5175%, marked), and 4 (76100%, excellent).

In addition, a patient satisfaction score (A =not sat-

isfied, B = somewhat satisfied, and C=highly satis-

fied) was recorded after completion of treatment.

Results

One month after the final treatment, six of 22 (27%)

patients showed marked improvement in the striae

(Table 1, Figure 1), with the other 16 showing mild

(grade 1) improvement. On the quartile grading

scale, the mean clinical improvement 1 month after

treatment was 1.5. The treated striae demonstrated

various improvements in color, with all those

showing excellent results being white (Table 1).

There were no significant differences according

to anatomic site.

H&E and Masson-trichrome staining showed that

average epidermal thickness (0.24 to 0.55mm,

po.05) and dermal thickness (1.97 to 4.03mm,po.01) were greater after treatment than at baseline(Figure 2, Table 1). Elastica von Gieson staining

gave similar results before and after treatment.

Pretreatment atrophy was noted in all patients.

LSCM analysis showed marked increases in the

immunoreactivity of procollagen type 1 one month

DERMATOLOGIC SURGERY1216

TREATMENT OF STR IAE DISTENSAE WITH FRACTIONAL PHOTOTHERMOLYS I S

after the end of treatment (Figure 3) but no changes

in the immunoreactivity of elastin and MMP-1.

The treatment was well tolerated. The patients de-

scribed the procedure as mildly to moderately un-

comfortable. There were no significant side effects

except mild erythema and pigmentation. Postlaser

erythema and crusts, lasting 1 day to 2 weeks, were

observed in all patients, whereas postinflammatory

hyperpigmentation was observed in only two of 22

patients. Allergic contact dermatitis to the anesthetic

topical gel was observed in one patient. Patient sat-

isfaction surveys paralleled the clinical improvements.

Discussion

Striae distensae are dermal scars characterized by

linear atrophic depressions. Many treatment mo-

dalities have been tried, with variable results. Topical

tretinoin cream was shown to improve appearance,5

and glycolic acid and ascorbic acid have had variable

outcomes.11 Intense pulsed light was shown to be

successful in the treatment of striae alba, but post-

inflammatory pigmentation occurred in 40% of pa-

tients.7 The 308-nm excimer laser has been shown to

temporarily repigment striae alba without improving

atrophy.1214 Treatment of striae distensae with

pulsed dye, carbon dioxide, and 1,450-nm diode

lasers have also been attempted.6,1517

Fractional photothermolysis uses arrays of micro-

scopic thermal damage patterns to stimulate a ther-

apeutic response.8 These arrays are produced in

various patterns by focusing the laser beam at spe-

cific depths in the dermis. The tiny areas of thermal

injury surrounded by uninjured tissue are called mi-

croscopic treatment zones (MTZs). MTZ density

and the space between MTZs can be varied for a

TABLE1. Clinical Improvement and Changes in Epidermal and Dermal Thicknesses

Patient

Color of the

Distensae

Average Clinical

Improvement

Epidermal Thickness Dermal Thickness

Pre/Post Pre/Post

1 White 3 0.02/0.06 1.5/4.3

2 Purple 1 0.13/0.23 2.07/3.8

3 White 2 0.03/0.04 2.0/3.7

4 Purple 1 0.05/0.05 1.5/2.3

5 Pink 1 0.06/0.06 1.95/5.3

6 Pink 1 0.75/0.95 1.85/3.45

7 Pink 1 0.11/0.15 2.05/3.7

8 Pink 1 0.05/0.18 2.35/3.35

9 Pink 1 0.09/1.03 2.0/4.05

10 Pink 1 0.08/0.15 1.05/4.5

11 Purple 1 0.12/0.25 1.95/3.9

12 Pink 1 0.04/0.08 2.33/3.3

13 Pink 1 0.91/1.15 1.21/3.35

14 White 2 0.08/1.02 1.68/4.50

15 Pink 1 0.04/0.09 2.31/3.75

16 Pink 1 0.07/1.02 2.09/5.55

17 Pink 1 0.75/1.25 1.97/4.21

18 White 3 0.94/1.18 2.98/4.05

19 Pink 1 0.18/0.23 1.65/4.3

20 Pink 1 0.09/1.03 1.96/4.03

21 White 4 0.52/1.12 2.13/3.74

21 White 3 0.07/0.83 2.76/5.63

Sum 33 5.18/12.15 43.34/88.76

Average 1.5 0.24/0.55 1.97/4.03

Average of the two observers.

35 : 8 :AUGUST 2009 1217

BAK ET AL

given energy level. In fractional photothermolysis,

tissue damage occurs in microscopic columns that

extend into the dermis and is not restricted to a

specific target tissue. Because uninjured tissue

surrounds each MTZ, keratinocytes have a shorter

migration path, and healing is much quicker. Frac-

tional photothermolysis recently showed effective-

ness in the treatment of atrophic scars,18 suggesting

that the approach might also improve striae, and few

reports have described the use of fractional photo-

thermolysis in the treatment of striae distensae.9,10 In

this study, we used fractional photothermolysis (the

Fraxel SR 1500 laser), which can penetrate up to

30% deeper than other lasers, delivering consistent

dosage control and optimizing lesion depths.

Our results suggest that this method may result in

clinical and histopathologic improvement of striae

Figure 1. One patient with striae alba had (A) the lesions onthe left upper arm at baseline and (B) the improved lesions 1month after two treatment sessions and (C) the lesions onthe right upper arm at baseline and (D) the improved lesions1 month after two treatment sessions. Another patient withstriae rubra had no significant changes between (E) baselineand (F) 1 month after two treatment sessions.

Figure 2. Skin biopsies of (A) an untreated abdominal striaeand (B) the same abdominal striae 1 month after final treat-ment. Note the increased collagen in the dermis and a mi-crothermal zone (arrows) with columns of altered collagen(Masson trichrome 200).

Figure 3. Laser scanning confocal microscopy of (A) an un-treated abdominal striae and (B) the same striae 1 monthafter final treatment, showing greater dermal immunoreac-tivity with antibody to procollagen type 1.



distensae. All striae that showed excellent improve-

ment were white, suggesting that fractional

photothermolysis is most effective for patients with

late-stage white striae. Long-term follow-up has

confirmed these results. Six months after the last

treatment, three of three patients with striae alba had

shown subjective improvement, whereas only two of

eight patients with striae rubra had improved

slightly, with the other six being in stationary state.

Histopathologically, a marked decrease in collagen

fibers and elastic tissues with thinned epidermis be-

cause of a flattening of the rete ridges characterize

late-stage striae. In early-stage striae, these findings

are less prominent, with perivascular infiltrates of

inflammatory cells being the predominant feature.

Thus, fractional photothermolysis, which induces

epidermal and dermal collagen regeneration, is es-

pecially effective in the treatment of striae alba. The

limited therapeutic outcome observed in many of our

patients may have been because of their early-stage

striae (mean 6 years).6,16,19 There were no statisti-

cally significant differences between anatomic sites.

Similar to previous reports, the side effects of treat-

ment were transient and limited to erythema, edema,

and pigmentation.20 No other adverse effects were

observed, including acneiform eruptions or herpes

simplex virus outbreaks.

Although we observed clinical improvements

1 month after two sessions of fractional photo-

thermolysis, additional studies are necessary to de-

termine the longevity of improvement. Optimization

of treatment protocols should be established through

clinical trials involving larger numbers of patients. In

addition, long-term side effects, complications, and

efficacy of treatment have yet to be established, ne-

cessitating further research to confirm our results.

Summary

Treatment of striae distensae with fractional photo-

thermolysis was effective and without significant

side effects. Treatment outcomes were better in pa-

tients with striae alba than in those with striae rubra.

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Address correspondence and reprint requests to: Sung EunChang, MD, Department of Dermatology and ResearchInstitute of Dermatology, University of Ulsan College ofMedicine, Asan Medical Center, 388-1 Pungnapdong Song-pagu, Seoul, 138-736 Korea, or e-mail: [email protected]



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