Background: Onion extract gel (OE) and 0.5% hydrocortisone, silicone and vitamin E lotion (HSE) are two over-the-counter preparations used to enhance the cosmesis of keloids and hypertrophic scars.
Objective: To determine the tolerability and efficacy of OE versus HSE versus placebo in subjects with keloids and hypertrophic scars.
Methods: Thirty subjects (> or =18 years) with keloids or hypertrophic scars were randomly assigned to one of three study preparations for 16 weeks. Scar volume was measured at baseline and weeks 4, 8, 12 and 16. Subjects and blinded investigators assessed scar parameters (induration, erythema, pigmentation alteration, pain, itching, tenderness and cosmetic appearance) and patient satisfaction at each visit using a visual analog scale (VAS). Data analysis included: mean percentage change (MPC) for subjects completing the study (n = 15); the mixed model test to determine differences between the groups over time; and the Kruskal-Wallis test for the analysis of differences in subjects' satisfaction within the three groups over 16 weeks for subjects who completed at least one follow-up visit (n = 21).
Results: All three preparations were well tolerated with the exception of a mild acneiform-like eruption in one OE patient. Significant improvements were obtained with OE in volume, length, width and induration and with HSE in volume, length, induration, erythema and pigmentation alteration. There was a trend showing that a higher percentage of subjects were satisfied with OE than with HSE or placebo. The Mix Model Analysis (MMA) showed significant improvements with OE over placebo in investigator cosmetic assessment, lesion induration, pigmentation and tenderness and with HSE over placebo in investigator cosmetic assessment, lesion induration, pigmentation and erythema. Improvements in erythema and pigmentation were significantly greater in HSE than in OE.
Conclusion: Both OE and HSE were more effective than placebo in the management of hypertrophic scars and keloids.