A comparative study of fractional carbon dioxide laser efficiency in the treatment of striae rubra and striae alba

INTRODUCTION

Striae distensae (SD), commonly known as stretch marks, are a prevalent dermatological condition characterized by linear atrophic dermal lesions that result from skin.¹ These marks can manifest as striae rubra, which are erythematous and slightly raised, or as striae alba, which are hypopigmented and atrophic, reflecting a more chronic stage of skin damage.^2,3 SD are not only a cosmetic concern but also contribute to significant psychological distress, particularly among women, who are disproportionately affected by this condition.⁴ The lesions frequently appear during periods of rapid skin stretching, such as puberty, pregnancy, or significant weight changes, and have been associated with conditions such as Cushing’s syndrome and Marfan syndrome.⁵ Furthermore, the use of corticosteroids, both topical and systemic, is a well-known precipitating factor. The pathogenesis of SD involves complex alterations in the dermal connective tissue framework, particularly affecting the extracellular matrix components such as collagen and elastin.⁶ Histologically, striae rubra exhibit increased vascularity and edema, whereas striae alba are marked by collagen reorganization and reduced vascularity.⁷ Despite their prevalence, there is no universally accepted standard treatment for SD. Traditional therapies, such as topical retinoids, hyaluronic acid, and microdermabrasion, offer limited efficacy and often require prolonged use to achieve modest improvements.⁸ Given the limitations of these conventional treatments, there is a growing interest in advanced therapeutic modalities that offer more substantial and lasting results.

Recently, laser therapy has emerged as a promising treatment option for SD, with fractional carbon dioxide (CO₂) laser therapy at the forefront.⁹ This laser modality works by creating controlled microthermal injury zones in the skin, promoting collagen remodeling and neocollagenesis while sparing adjacent tissue.¹⁰ The fractional CO₂ laser is particularly effective due to its ability to penetrate deeply into the dermis and stimulate fibroblast activity, resulting in improved skin texture and appearance.¹¹ Previous studies have demonstrated the efficacy of fractional CO₂ lasers in treating various dermatological conditions, including scars and photoaging, making them an attractive option for managing SD.^12,13 Despite promising outcomes, there is a paucity of data directly comparing the effectiveness of fractional CO₂ laser treatment on different types of striae, such as striae rubra and striae alba. Most existing studies focus on short-term improvements without comprehensively addressing long-term efficacy and patient satisfaction. In addition, there is a need for more rigorous clinical trials to establish standardized protocols regarding laser parameters, treatment intervals, and the number of sessions required to optimize outcomes.

The objective of this study is to evaluate the efficacy of fractional CO₂ laser therapy in treating striae rubra versus striae alba. We hypothesize that early intervention with fractional CO₂ lasers can lead to significant improvements in both the texture and appearance of these lesions, with variations in response depending on the type of striae. This study aims to provide robust clinical evidence to guide dermatologists in adopting laser therapy as a standard treatment for SD, ultimately improving patient outcomes and satisfaction. By addressing these research objectives, we hope to contribute valuable insights into the management of this common yet challenging dermatological condition.

MATERIAL AND METHODS

RESULTS

The study included 60 participants, equally divided between the striae rubra (n = 30) and striae alba (n = 30) groups. The average age was similar in both groups, with the striae rubra group having a mean age of 28.2 years (standard deviation [SD] ± 7.9) and the striae alba group having a mean age of 27.2 years (SD ± 8.5), showing no statistically significant difference (P = 0.643). Gender distribution was also comparable, with 56.7% males and 43.3% females in the striae rubra group and 53.3% males and 46.7% females in the striae alba group (P = 0.793).

Fitzpatrick skin types were similarly distributed, with no significant differences (P = 0.903). Both groups showed similar mean body mass indexes (BMIs): 26.8 kg/m² (SD ± 6.3) for striae rubra and 25.8 kg/m² (SD ± 6.7) for striae alba (P = 0.615). Lesion sites were predominantly on the shoulder for both groups (40.0% for striae rubra and 43.3% for striae alba), with similar distributions for other body sites such as the abdomen, hips, and extremities, and no significant differences (P = 0.970). The baseline characteristics between the groups were well matched, allowing for a balanced comparison in subsequent analyses [Table 1].

At the 4-week mark, most participants in both the striae rubra and striae alba groups showed no improvement in striae width and skin texture, with 90% of striae rubra and 97% of striae alba participants showing no change. By 8 weeks, the majority had <25% improvement in width (94% for striae rubra and 86% for striae alba) and similar percentages for skin texture, with no significant differences between groups (P > 0.5). At 20 weeks, the striae rubra group exhibited greater improvements [Figures 1 and 2], with 30% achieving 50–75% width reduction and 7% achieving over 75%, compared to 10% and 0% in the striae alba group [Figures 3 and 4], respectively [Table 2]. Skin texture also improved more in the striae rubra group, but overall differences between groups remained statistically non-significant at all-time points (P > 0.1).

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Figure 1:

Improvement of striae alba over the left shoulder at (a) baseline, (b) week 4, (c) week 8 and (d) week 20.

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Figure 2:

Improvement of striae alba over the right shoulder at (a) baseline, (b) week 4, (c) week 8 and (d) week 20.

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Figure 3:

Improvement of striae rubra over the left abdomen at (a) baseline, (b) week 4, (c) week 8 and (d) week 20.

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Figure 4:

Improvement of striae rubra over the right abdomen at (a) baseline, (b) week 4, (c) week 8 and (d) week 20.

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At the 20-week follow-up, patient satisfaction levels were similar between the striae rubra and striae alba groups, with 23.3% of the striae rubra group and 16.7% of the striae alba group reporting marked satisfaction (VAS >75%). Moderate satisfaction was reported by 26.7% of the striae rubra group and 23.3% of the striae alba group. Mild satisfaction was higher in the striae alba group (26.7% vs. 16.7%), whereas poor satisfaction was identical in both groups at 33.3%. In terms of adverse effects, 20.0% of the striae rubra group experienced immediate adverse effects compared to 6.7% of the striae alba group (P = 0.495) with erythema and burning sensation being the most common immediate adverse effect in both groups. Late adverse effects were similar between groups, with 20.0% in the striae rubra group and 23.3% in the striae alba group with post-inflammatory hyperpigmentation being the most common [Table 3]. A majority of participants reported no adverse effects, with 60.0% in the striae rubra group and 70.0% in the striae alba group, indicating generally comparable outcomes between the two groups with no statistically significant differences (P > 0.1). Patients with Fitzpatrick skin types III and IV, low BMI, and no topical corticosteroid usage history showed good prognosis, whereas skin types V, high BMI, and corticosteroid usage history showed vice versa.

DISCUSSION

Our study demonstrated that fractional CO₂ laser treatment effectively improved both striae rubra and striae alba, with a slightly better outcome for striae rubra in terms of overall improvement and patient satisfaction. These results are consistent with the findings of Elmorsy et al. (2021), who reported significant clinical improvements in both types of striae with no significant differences between them.¹⁴ In our study, 17% of participants with striae rubra and 10% with striae alba achieved >75% overall improvement. This suggests that while fractional CO₂ laser treatment is effective for both types, striae rubra, which are in a more active inflammatory stage, might respond more robustly due to their increased vascularity, which enhances the laser’s effects.¹⁵

Comparatively, Yang and Lee (2011) assessed the efficacy of nonablative fractional photothermolysis and ablative fractional CO₂ laser resurfacing for treating SD and found both modalities to be effective and safe, particularly in Asian skin, but did not observe greater clinical improvement with either modality.¹¹ In their study, the percentage of patients reporting “good” to “excellent” improvement was lower than in ours, possibly due to differences in skin type and the chronicity of the lesions treated. Kaewkes et al. (2022) evaluated the long-term efficacy of a fractional picosecond 1064-nm laser specifically for striae alba in individuals with darker skin and found moderate to marked improvement in 90% of subjects, with only a 10% incidence of transient post-inflammatory hyperpigmentation.¹⁶ These results are comparable to our findings for striae alba, suggesting that newer laser technologies may offer similar efficacy across different skin types. Lee et al. (2010) demonstrated a positive therapeutic effect using ablative fractional CO₂ lasers for late-stage SD, reporting high participant satisfaction with 52% achieving 50–75% improvement, which aligns closely with our findings of high satisfaction levels and marked improvement in the striae rubra group.¹⁷ Malekzad et al. (2014) similarly showed significant improvements in striae alba with the Star Lux 500 laser, suggesting that fractional lasers, in general, provide substantial benefits in managing SD, regardless of the specific type or laser technology used.¹⁸

The biological differences between striae rubra and striae alba may account for the observed treatment outcomes in our study. Striae rubra, being in the inflammatory stage, have increased vascularity and cellular activity, which might enhance the fractional CO₂ laser’s ability to promote collagen remodeling and skin renewal.¹⁹ The laser’s microthermal zones create controlled damage, stimulating the body’s natural wound-healing response and encouraging new collagen and elastin production. In contrast, striae alba, representing a more chronic phase, have reduced vascularity and dermal thinning, making it more challenging to achieve significant improvement.²⁰ The limited blood supply and altered extracellular matrix in striae alba may hinder the laser’s effectiveness in stimulating substantial tissue regeneration.²¹ This difference in the biological environment likely contributes to the better outcomes observed in striae rubra, as the laser can leverage the active cellular processes to enhance skin repair and improve striae appearance. An increase in the pulse duration leads to deeper penetration causing more thermal damage in the lesional tissue and to the surrounding areas due to increased heat diffusion, in our study, the first session was started with 1 ms of pulse duration and increased 1 ms in each session with reaching 3 ms in the third session based on the tolerability of the patient to the burning sensation. The pulse interval was kept constant at 6 ms in all sessions.

The strengths of our study include a well-balanced design with equal numbers of participants in both striae rubra and striae alba groups, ensuring a fair comparison. The standardized treatment protocol and comprehensive follow-up assessments allowed for consistent and reliable outcome measurement. However, the study also has limitations, including the relatively small sample size and the subjective nature of patient satisfaction assessments. Furthermore, the lack of long-term follow-up limits our understanding of the sustained efficacy of fractional CO₂ laser treatment. The inclusion of objective skin analysis technologies in future studies could enhance the precision of outcome evaluations.

Clinically, this study supports the use of fractional CO₂ laser therapy as a viable treatment option for both striae rubra and striae alba, offering a non-invasive approach to improving skin texture and appearance. While striae rubra may respond more favorably, the treatment can still provide benefits for striae alba, making it a versatile option in dermatological practice. For future research, larger studies with extended follow-up periods are recommended to assess the long-term efficacy and safety of fractional CO₂ lasers. In addition, exploring the combination of laser therapy with adjunctive treatments, such as topical agents or microneedling, may enhance outcomes further. This study contributes valuable insights into the management of SD, guiding clinicians in optimizing treatment strategies to improve patient outcomes and satisfaction.

CONCLUSION

The study demonstrates that fractional CO₂ laser therapy effectively improves both striae rubra and striae alba, with slightly better outcomes for striae rubra due to its increased vascularity and active cellular processes. Fractional CO₂ laser therapy is a safe, non-invasive treatment option that enhances skin texture and appearance in patients with SD, making it a versatile addition to dermatological practice.