EVIDENCE-BASED ANSWER
NO ONE TREATMENT IS BEST (strength of recommendation [SOR]: C, meta-analysis of heterogenous studies); no good evidence exists comparing treatments with each other.
Triamcinolone injections, triamcinolone injections combined with excision, and cryotherapy all improve hypertrophic and keloid scars (SOR: C, case series studies).
Silicone gel products have weak evidence of efficacy (SOR: C, Cochrane review with no clear recommendation).
Evidence summary
The TABLE summarizes the evidence for the best-studied treatments.1-5 A systematic review of 396 studies, 36 of which were included in an accompanying meta-analysis, concluded that, overall, any treatment gave patients a 70% (95% confidence interval [CI], 49%-91%) chance of improvement.6 The mean improvement in scar appearance or symptoms was 60% for all the studies combined (no CI reported).
The review found no statistically significant difference between outcomes of 27 different treatments or combinations of treatments. The authors concluded that no optimal evidence-based therapy exists and recommended choosing treatment based on cost and adverse effect profile.6
TABLE
What the evidence tells us about these scar treatments
| Treatment | Study design | Number of scars treated | Inclusion/ exclusion criteria | Results | Comment |
|---|---|---|---|---|---|
| Triamcinolone injections1 | Case-control | 195 | None | >90% of scars showed moderate to marked improvement in 3 wk | Only study with control group; no controls showed improvement |
| Triamcinolone injections plus excision2 | Case series | 58 | None | 100% of patients were symptom-free in 5 wk | No recurrences in 91.9% of keloids and 95.2% of hypertrophic scars at a mean follow-up of 30.5 mo |
| Cryotherapy study 13 | Case series | 119 | Only fair-skinned patients | 61.3% of patients had good to excellent results; most patients needed ≥3 treatments. Hypertrophic scars responded better than keloids | Side effect of hypopigmentation limits use of this therapy in dark-skinned patients Lesions <2 y responded better than older scars (P<.5); no recurrences were noted |
| Cryotherapy study 24 | Case series | 65 | None | Complete flattening in 73% of scars; improvement in 17% | All lesions that responded showed hypopigmentation that persisted in mean 31-mo follow-up 6 lesions didn’t respond; all had been present >2 y |
| Silicone gel products5 | Cochrane review | NA | NA | Weak evidence of reduction in scar thickness and color | Poor-quality studies, highly susceptible to bias |
| NA, not applicable | |||||
Many studies have limitations
Studies often don’t distinguish between hypertrophic and keloid scars, although much evidence supports important differences in their natural histories and response to therapy.7 Hypertrophic scars may resolve spontaneously, can improve with surgical revision, and are less likely to recur.
Moreover, many studies looked only at initial response, although good initial response to therapy doesn’t translate into a low recurrence rate, particularly for keloid scars. Studies were also flawed by lack of controls, nonvalidated outcome measures, and small size.
No available evidence supports using over-the-counter products such as Mederma and other creams, gels, and oils, to treat scars.
Recommendations
The American Academy of Dermatology does not make any recommendations about hypertrophic or keloid scars.
The International Clinical Recommendations on Scar Management (written for the International Advisory Panel on Scar Management) recommend silicone gel sheeting and intralesional corticosteroids as first-line therapy, based on a systematic review of the clinical literature. For secondary management, the authors accepted localized pressure therapy, specific wavelength laser therapy, and surgical revision with adjuvant silicone gel therapy as standard practice based on expert opinion. They conclude that many standard practices and emerging therapies need to be studied in well-designed trials before being conclusively recommended.8