Arnica appears effective in reducing experimentally induced bruising. - GreenMedInfo Summary
Accelerated resolution of laser-induced bruising with topical 20% arnica: a rater-blinded randomized controlled trial.
Br J Dermatol. 2010 Sep;163(3):557-63. PMID: 20412090
Department of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
BACKGROUND: Dermatological procedures can result in disfiguring bruises that resolve slowly.
OBJECTIVES: To assess the comparative utility of topical formulations in hastening the resolution of skin bruising.
METHODS: Healthy volunteers, age range 21-65 years, were enrolled for this double (patient and rater) blinded randomized controlled trial. For each subject, four standard bruises of 7 mm diameter each were created on the bilateral upper inner arms, 5 cm apart, two per arm, using a 595-nm pulsed-dye laser (Vbeam; Candela Corp., Wayland, MA, U.S.A.). Randomization was used to assign one topical agent (5% vitamin K, 1% vitamin K and 0·3% retinol, 20% arnica, or white petrolatum) to exactly one bruise per subject, which was then treated under occlusion twice a day for 2 weeks. A dermatologist not involved with subject assignment rated bruises [visual analogue scale, 0 (least)-10 (most)] in standardized photographs immediately after bruise creation and at week 2.
RESULTS: There was significant difference in the change in the rater bruising score associated with the four treatments (anova, P=0·016). Pairwise comparisons indicated that the mean improvement associated with 20% arnica was greater than with white petrolatum (P=0·003), and the improvement with arnica was greater than with the mixture of 1% vitamin K and 0·3% retinol (P=0·01). Improvement with arnica was not greater than with 5% vitamin K cream, however.
CONCLUSIONS: Topical 20% arnica ointment may be able to reduce bruising more effectively than placebo and more effectively than low-concentration vitamin K formulations, such as 1% vitamin K with 0·3% retinol.