Silicone Sheets and Patches for Scar Treatment: A Comprehensive Clinical Review

This scientific report synthesizes current evidence on silicone-based interventions for scar management, analyzing efficacy across different scar types, application protocols, and underlying mechanisms of action. Silicone therapy represents one of the most widely recommended non-invasive approaches for problematic scarring, with a substantial body of clinical research supporting its use.

Mechanism of Action: Current Understanding

The precise mechanism by which silicone products improve scar appearance remains incompletely understood despite decades of clinical use. Several theoretical pathways have been proposed based on experimental and clinical evidence.

The most substantiated theory involves hydration and occlusion effects. Silicone creates a semi-occlusive barrier that increases stratum corneum hydration, normalizing the excessive transepidermal water loss typically observed in scar tissue513. This hydration appears to restore better homeostasis, potentially suppressing hyperactive fibroblast activity and excessive collagen production13. Research indicates that wound coverage changes in hydration likely constitute the primary mechanism rather than any pharmacological effect of silicone itself5.

No evidence supports direct penetration of silicone into the scar tissue. Studies by Ahn (1989) and Swanson (1974) found no silicone in the scar or stratum corneum1. Furthermore, Quinn (1985) found no significant differences in pressures, surface temperature, or oxygen tension beneath silicone gel1.

Additional proposed mechanisms include:

Static electricity generated by friction-activated silicone sheeting, which may influence collagen alignment and deposition5 6
Bacterial barrier function preventing infection-induced excessive collagen production20
Inhibition of mast cell activity, which may reduce inflammation and fibrosis6 13
Regulation of growth factors and collagenases, restoring balance in excess scar tissue7

Types of Silicone Products for Scar Management

Silicone Gel Sheets

These are soft, self-adhesive sheets composed of cross-linked polymers of dimethylsiloxane (polydimethylsiloxane or PDMS)53. They are reusable, flexible, and designed to conform to body contours3. Product examples include Scar Fx®, which features 100% silicone material that remains transparent for discreet positioning3.

Topical Silicone Gels

These liquid formulations dry within 4-5 minutes to form an ultra-thin, transparent layer that works continuously1920. They offer advantages in areas where sheets may be difficult to apply or when discretion is required, as they can be covered with makeup after drying19.

Combination Products

Some products incorporate additional elements such as fabric backing for improved durability or mineral oils for enhanced effects. These combination approaches may offer benefits for specific applications or anatomical locations19.

Clinical Evidence of Efficacy by Scar Type

Hypertrophic Scars

Hypertrophic scars—characterized by excess collagen confined within original wound boundaries—show significant response to silicone therapy. A Cochrane systematic review of 20 trials (873 participants) found silicone gel sheeting produced statistically significant reduction in scar thickness (mean difference -2.00, 95% CI -2.14 to -1.85) and color improvement (risk ratio 3.49, 95% CI 1.97 to 6.15)1. However, these studies had methodological limitations.

A meta-analysis of six randomized controlled trials (375 patients) confirmed that topical silicone gel significantly reduced pigmentation (SMD = -0.55 [-0.83 to -0.26], P = .0002), height (SMD = -0.73 [-1.02 to -0.44], P < .00001), and pliability scores (SMD = -0.49 [-0.95 to -0.03], P = .04) compared to placebos or no treatment4.

Keloid Scars

Keloid scars—which extend beyond original wound margins—appear more resistant to treatment but may still benefit from silicone therapy. In one clinical study, after silicone gel application, 60% of scars (including keloids) were downgraded to normal appearance (Grade I), while 20% became mildly hypertrophic (Grade II), and 20% remained severely hypertrophic or keloid (Grades III and IV)20.

Silicone products are recommended for long-term treatment of keloid scars, though complete resolution is less common than with hypertrophic scars38.

Burn Scars

For post-burn scarring, combination therapy shows promise. A randomized controlled trial demonstrated that silicone gel and silicone gel sheets combined with pressure garments were more effective than pressure garments alone in improving scar irregularity at 2, 4, 8, 16, and 20 weeks post-treatment2. Scar stiffness improved at 8 and 12 weeks in both silicone intervention groups2.

Notably, the study found no significant difference between silicone gel and silicone gel sheet on the Vancouver Scar Scale outcomes, suggesting similar efficacy between these delivery methods for burn scars2.

Surgical Scars

For post-surgical scars, preventive application shows efficacy. Meta-analysis data confirms topical silicone gel effectiveness in post-operative scar prevention4. One observational study of 15 subjects using a novel 100% silicone gel twice daily showed significant improvement in Vancouver Scar Scale and Observer Scar Assessment Scale scores as early as 14 days, with continuing improvement through 84 days14.

Atrophic Scars

Limited evidence exists for atrophic scars, particularly acne scarring. However, one study found that adding topical silicone gel to ablative Er:YAG laser treatment resulted in significantly less roughness at weeks 4 and 12 compared with placebo (p < 0.05), suggesting potential benefits as an adjunctive therapy12.

Application Protocols: Evidence-Based Recommendations

Timing of Initiation

For optimal results, silicone therapy should begin:

After complete wound closure, typically 5-10 days post-injury7 20
Once full re-epithelialization occurs, approximately 2 weeks after wound closure8
After suture removal for surgical scars3

Early intervention appears critical, as scar hypertrophy develops in most cases (96%) within 3 months after surgery8. However, silicone treatment has shown effectiveness even for scars present longer than 12 months, though optimal results occur with immature, actively changing scars8.

Recommended Wearing Duration

Clinical evidence supports the following wearing schedules:

Ideally 12-24 hours daily, with longer contact time correlating with better outcomes8
Minimum effective duration of at least 4 hours daily, though improvements are less significant than with continuous wear8
Gradual acclimatization recommended: begin with 4 hours daily for two days, then progressively increase to target duration16

Treatment Course Length

Recommended treatment durations from the literature:

Minimum initial course of 2-3 months for both hypertrophic and keloid scars8
Extended therapy of 6 months may prevent recurrence, particularly for keloid scars8
Standard recommendation of 90 days for initial evaluation, with possible extension based on response16 19
For immature scars remaining in active phase, treatment may extend beyond 6 months8

Replacement and Maintenance

Proper product maintenance improves outcomes and cost-effectiveness:

Silicone sheets require daily cleaning with mild soap and water, air drying, and proper storage16 19
With proper care, sheets typically remain effective for 6-8 weeks before replacement is necessary19
Some products (e.g., Neo G Silicone Strips) are designed for 28 days of continuous use per strip10
Silicone gel typically requires reapplication twice daily14 20

Guidelines for Optimal Use Based on Scar Characteristics

Scar Age Considerations

Fresh scars (< 3 months): Most responsive to silicone therapy; should begin treatment promptly after wound closure7 8
Mature scars (> 12 months): May still improve but require longer treatment duration and have less dramatic results7 8
Immature scars with active symptoms (redness, itching, pain): Particularly good candidates for intervention8

Scar Type and Risk Stratification

Silicone therapy should be prioritized for:

Patients with previous hypertrophic or keloid scarring history8
Individuals with darker skin complexions who have higher keloid risk (6-16% incidence)8
Younger patients8
Patients with problematic wound healing8
Wounds in high-risk anatomical locations (lower face, neck, upper arms, ear lobes)1 8

Side Effects and Contraindications

Contraindications

Silicone scar products should not be used in the following circumstances:

Known hypersensitivity to silicone or product components6 10
Open wounds, weeping wounds, or broken skin6 7 10 16
Third-degree burns before complete healing6
Dermatological conditions disrupting skin integrity (severe acne, psoriasis)1
Infected wounds10
Before suture removal in surgical wounds6

Adverse Effects

Reported adverse effects are generally mild and include:

Skin rashes and contact dermatitis requiring discontinuation (rarely)20
Mild skin desquamation20
Potential skin maceration with prolonged occlusion, especially in warm climates or during physical activity10
Adhesive-related skin irritation, which can be managed by temporary discontinuation followed by gradual reintroduction16

Limitations in Current Evidence

Despite widespread clinical adoption, several limitations exist in the current evidence base:

Many studies demonstrate high susceptibility to bias and methodological issues1
The exact mechanism of action remains incompletely understood1 6 13
Direct comparisons between silicone formulations are limited2 4
Some studies show newer interventions may outperform silicone sheets for specific applications17

An ongoing single-blinded, randomized trial (BEST Group trial) aims to provide more definitive evidence regarding silicone sheeting efficacy using objective outcome measures including laser Doppler imaging and high-frequency ultrasound15.

Conclusion

Silicone-based scar interventions represent an evidence-supported, non-invasive first-line therapy for problematic scarring. Current clinical evidence demonstrates efficacy for various scar types, particularly hypertrophic and post-surgical scars, with moderate effectiveness for keloid scars. The mechanism appears primarily related to occlusion, hydration, and subsequent normalization of fibroblast activity rather than pharmacological effects of silicone itself.

Optimal outcomes depend on early intervention, consistent application (ideally 12-24 hours daily), and treatment courses of at least 3 months. While generally well-tolerated, silicone products remain contraindicated on open wounds and in patients with silicone sensitivity. Future research should focus on refining protocols for specific scar types and clarifying the precise mechanisms of action to potentially enhance therapeutic efficacy.

Silicone Treatment for Scars

Tuesday, March 25, 2025