Currently accepted
conservative treatments of
hypertrophic scars are limited to
steroid injections,
radiation therapy, and
silicone occlusive
therapy. However, the use of Mederma for these problematic lesions has become quite prevalent in the clinical setting. Little scientific evidence exists to support the efficacy of this product in reducing
hypertrophic scars. The aim of this study was to study the effects of Mederma on
hypertrophic scars in the rabbit
hypertrophic scar model, allowing the histologic quantification of
scar elevation, dermal
collagen organization, vascularity, and
inflammation and the gross examination of
scar erythema. Full-thickness
wounds down to cartilage, four per ear, were created in four New Zealand White rabbits, for a total of 32
scars. Twenty-eight days after the initial wounding, the
hypertrophic scars were photographed, and treatment of half of the
scars on each ear was begun with Mederma three times per day for a total of 4 weeks. The untreated
scars served as control
scars and were left exposed to air. After 4 weeks of treatment, the
scars were once again photographed. The rabbits were then killed, and the
scars were analyzed histologically. The pretreatment and posttreatment photographs were compared by using computer quantification of magenta, yellow, and cyan expression within the
scars. Histologic analysis demonstrated no significant reduction in
scar hypertrophy or
scar elevation index. However, a significant improvement in dermal
collagen organization was noted on comparing Mederma-treated
scars with untreated control
scars (p < 0.05). No significant difference in dermal vascularity or
inflammation was noted. Computer analysis of the
scar photographs demonstrated no significant reduction in
scar erythema with Mederma treatment. The active product in Mederma, allium cepa, has as its derivative
quercetin, a
bioflavonoid noted for its antiproliferative effects on both normal and malignant cells, and its
antihistamine release effects. These properties could theoretically prove beneficial in reversing the inflammatory and proliferative responses noted in
hypertrophic scars. Despite the authors' inability to demonstrate a reduction in
scar hypertrophy, the improvement in
collagen organization noted in the Mederma-treated
scars suggests it may have an effect on the pathophysiology of
hypertrophic scar formation.