Home » Peer-Review » Body Contouring » The treatment of striae – Where is the evidence?
Striae distensae (SD), also known as stretch marks, are common cutaneous lesions characterized by linear bands of atrophic skin1. They represent dermal scars with epidermal atrophy and pose a common source of cosmetic concern. Striae distensae result from changes in the collagen, caused by rapid stretching of the skin, and are usually multiple and symmetrically distributed2. The most commonly affected sites include the abdomen, outer thighs, and breasts2,3. Even though the exact pathogenesis is poorly understood, striae are commonly associated with mechanical stress (rapid weight changes and growth spurt) and hormonal changes (pregnancy, oral contraceptive use, increased adrenocortical function, and corticosteroid therapy)3. The evolution of SD proceeds through several stages. In the acute stage, they may be thin, pink, and even pruritic. Over time, they usually enlarge in length and width, may become raised, and acquire a reddish-purple appearance (striae rubra — SR). Finally, they become flat or depressed and hypopigmented (striae alba — SA)3,4.
Histologically, SD demonstrates a similar appearance to atrophic scars. They display epidermal atrophy, flattening of the rete ridges, loss of thickness in the dermis, as well as retraction and loss of collagen and elastin3,4.
Several treatments have been utilized with variable therapeutic outcomes, cost, and side-effects. At present, there is no universally accepted treatment for all types of SD and in all skin types, making improvement rather than complete resolution a more realistic clinical expectation4. Available treatments include topical agents, chemical peels, microdermabrasion, and a multitude of both ablative and non-ablative energy-based devices.
eight studies were found that used topical therapy as a treatment of SD between 1994 and 2017. Treatment therapy included: Punica granatum seed oil, Croton lechleri resin extract, galvanopuncture, platelet-rich plasma (PRP), topical tretinoin, glycolic acid, and ascorbic acid. Needling and micro-dermabrasion were also reported in a small number of studies.
Of the studies which used energy-based devices as a treatment, 16 of these were comparative studies, four were combination studies and the remaining 10 were non-comparative/non-combination studies. Of the studies which used topical therapy as a treatment, three of these were comparative studies, three were combination studies, and two were non-comparative/ non-combination studies.
Pongsirhadulchai et al. reviewed the efficacy and safety of fractional radiofrequency (FRf) for SA in 33 subjects with SA affecting the thighs, buttocks, and abdomen. Three sessions of FRf were undertaken at 4-weekly intervals, and post-treatment results were assessed using digital Pictzar software to determine if the length and width of SA had reduced. They found a significant reduction in the length and width of the SA from baseline (P<0.001). Histopathology of the SD was also reviewed post-treatment, which demonstrated collagen and elastin bundles were found to be significantly increased5.
Clementoni and Lavgno treated 12 Caucasian patients with three sessions of fractional non-ablative 1565 nm fractional laser and reviewed the results at 3-months post-therapy. Good clinical improvement was found in all patients treated, with the volume of the depressions and improvement of lesion colour being the subcategories that were optimized the most. Transient side-effects included transient erythema and oedema; however, neither were long lasting6.
Another study involving 22 patients with SD used two sessions of 1550 nm fractional non-ablative laser at 4-weekly intervals and evaluated the results using clinical photography and skin biopsies. Twenty-seven percent showed 'good to excellent' improvement and the remaining 63% showed various degrees of improvement. Skin biopsy showed that both epidermal and dermal thickness increased as well as the immunoreactivity of procollagen type 17. Interestingly, the lesions which responded the best were SA, given that SA is usually more recalcitrant to treatment than SR due to the maturity of the striae; however, reduction in vascularity was not an outcome measure.
Park et al. carried out a pilot study on 16 patients with either SA or SR in which they received three treatments of microneedling, every 4 weeks. Outcomes were assessed using a quartile grading scale and 43.8% demonstrated marked to excellent improvement and overall 37.5% of patients were highly satisfied, 50% somewhat satisfied, and 12.5% unsatisfied8.
Gokalp compared the outcome of SR and SA using the 1550 nm non-ablative fractional laser in pregnancy-induced SD in 16 women. Each candidate had five sessions at 4-weekly intervals. It was found that overall strial width and length reduced at one month and one-year post-treatment respectively9.
A comparative split-striae study comparing two different settings of long-pulsed Nd:YAG laser to treat both SR (N=23) and SA (N=22) using 75 versus 100 J/cm2 was performed. A significant improvement was found in SA treated with 100J/cm2, while a greater improvement was found in treatment with 75 J/cm2 in the SR segment of the study. Again, both collagen and elastin increased histologically post treatment10.
El Taieb and Ibrahim compared fractional CO2 laser versus IPL in 40 patients with SD. Both treatments modalities showed significant improvement, with fractional CO2 laser showing improvement sooner than IPL — results evident after five sessions versus ten sessions with IPL11.
A prospective, randomized, comparative trial with fractionated bipolar radiofrequency and bipolar radiofrequency in conjunction with infrared light to treat SD on the abdomen of 22 patients (with a total of 384 SR and SA) was performed. Results demonstrated that mean striae depth reduced by 21.64% six months post-treatment in the combination group versus an increase of 1.73% in the control group. Histological review post-treatment demonstrated thicker collagen fibres in the non-control group12.
An interesting comparative study comparing microneedling therapy with a fractional CO2 laser in the treatment of SD in 20 Egyptian female patients found microneedling to be more beneficial with 90% of patients showing clinical improvement versus only 50% in the CO2 laser group13.
Wang et al. compared two different wavelengths of non-ablative lasers (1540 nm and 1410 nm) in the treatment of SD in a split-abdomen study involving six patients. Both clinical improvement (based on photography) and histological improvement from skin biopsy were found in each group, with no statistical differences. Skin biopsy demonstrated increased epidermal and dermal thickness, increased collagen and elastin density in comparison to pre-treatment biopsies14.
A study comparing the long-pulsed Nd:YAG 1064 nm versus the 2940 nm tunable pulse width Er:YAG was performed in 22 patients (SR=3, SA=17). Both Treatment types were randomly allocated to both sides of the body, and all subjects were treated weekly for a total of three sessions. Patients with SA lesions were found to have a poor response to treatment on photographic review of treatment, whereas patients with SR had moderate responses (on both sides). Interestingly, although clinical outcome was poor in both groups, histological improvement was still noted post-treatment, in all samples, in comparison to pre-treatment skin biopsies15.
A randomized, controlled trial comparing two modalities of fractional lasers (ablative CO2 versus non-ablative 1550 nm Er:Glass) in a split-abdomen study on 24 patients showed no significant difference between the two groups (three treatments in total 4-weekly) despite both groups showing clinical and histological improvement16.
The use of PDL for both SR and SA in 22 patients demonstrated a moderate improvement in the erythema of SR with little change in SA17.
A study comparing the combination of fractional CO2 with PDL versus fractional CO2 alone in the treatment of 88 SA lesions of three female patients showed the combination treatment to be more effective with a significant greater reduction in post-treatment surface area (P=0.03) and a significantly higher VAS score (P<0.001)18.
Ryu et al. reviewed combination therapy with fractionated microneedle radiofrequency (RF) and fractional CO2 laser in SD on 30 patients with moderate to severe striae. A third were treated with fractional CO2 laser only, a third with microneedle RF only, and the final third used a combination of both treatments. Mean improvement using VAS were 2.2, 1.8, and 3.4 respectively. Histology demonstrated thickened epidermis and higher number of collagen fibres in the combination treated sites19.
Naein and Soghrati carried out a controlled trial on 92 patients with SD, comparing fractional CO2 laser in group one (5 sessions of laser, 2–4 weekly intervals) with group two, who were treated with 10% glycolic acid plus 0.05% tretinoin cream at night for the duration of the study. Group one showed a significantly reduced surface area of SD compared with group two, and the mean VAS was higher in group one. Although, no statistically significant difference was noted20.
Suh et al. reviewed the outcome of treating abdominal SD in 37 Asian patients, initially with RF in combination with PDL, and then with two subsequent sessions of PDL at 4 and 8 weeks. Subjective assessment demonstrated 89.2% of patients showed 'good and very good' overall improvement and 59.4% demonstrated 'good and very good' improvement in regards to elasticity, with the authors deducing RF with PDL an overall effective treatment21.
Another study among 19 Asian patients used the combination of intradermal RF combined with autologous PRP, at 4-weekly intervals for a total of three sessions. Only one patient had an excellent improvement, seven had marked improvement, six had moderate improvement, and five mild improvement. None had a worse outcome and 63.2% of patients were satisfied to very satisfied22.
A study looking at comparison between two different combinations of topical therapy in SD (20% glycolic acid/0.05% tretinoin versus 20% glycolic acid/10% L-ascorbic acid) in 10 patients, whereby they treated half of the area with each treatment subset daily for 12 weeks, found both combinations improved the appearance of SD as well as increase epidermal thickness and decrease papillary dermal thickness in comparison to untreated SD23.
Although numerous attempts have been made to improve the clinical appearance of SD, no 'gold standard' modality has emerged to date that consistently restores SD completely.
In terms of topical agents, tretinoin and glycolic acid have been shown to produce good results against the appearance of recent SD. These treatments, however, offer little to no benefit against mature SD. The use of energy-based treatment methods, often in combination, has been shown to offer clinical improvement due to the reorganization of the collagen and dermal remodelling.
The CO2 laser was found to be the modality with the most available evidence (six RCTs, three non-randomized controlled studies, and one observational study). RF was found to be the most frequently employed modality (11 studies), followed by the CO2 and pulsed dye lasers (10 and five studies, respectively).
Non-ablative fractional lasers have demonstrated reduction in both length and width of SD; however, the longest follow-up documented is that of 1-year post-treatment. Even if results have not been clinically beneficial, the histology has almost always demonstrated an increase in collagen elastin bundles from pre- and post-treatment skin biopsies highlighting the potential discrepancy between clinical and histological improvement.
Importantly, it is almost impossible to compare treatment outcomes between the studies presented. This is partly because each laser study may use a different number of treatments, with different intervals and different fluencies (high versus low), added to the difference in outcome measurements methodology, which was inconsistent in studies. Some studies used subjective measurement from the patient, others clinical photography with independent/blinded assessors or VAS scores.
Tretti Clementoni M, Lavagno R. A novel 1565 nm non-ablative fractional device for stretch marks: A preliminary report. J Cosmet Laser Ther. 2015;17(3):148–55.
Jiménez GP, Flores F, Berman B, et al. Treatment of striae rubra and striae alba with the 585-nm pulsed-dye laser. Dermatol Surg. 2003;29(4):362–5.
Naein FF, Soghrati M. Fractional CO2 laser as an effective modality in treatment of striae alba in skin types III and IV. J Res Med Sci. 2012:17(10):928–33.
Ash K, Lord J, Zukowski M, et al. Comparison of topical therapy for striae alba (20% glycolic acid/0.05% tretinoin versus 20% glycolic acid/10% L-ascorbic acid). Dermatol Surg. 1998;24(8):849–56.