Accelerated resolution of laser-induced bruising with topical 20% arnica: a rater-blinded randomized controlled trial

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.