Arnica Tincture Fot the Treatment of Cutaneous Leishmaniasis II.

Cutaneous leishmaniasis (CL) is a parasitic disease caused by more than 20 different species of the protozoan parasite Leishmania. CL usually begins with a papule at the site of the sandfly bite, which enlarges to form a nodule that progresses to an ulceration, or a scaly or warty plaque, over a period of 1 to 3 months.

The exact incidence of CL is not known. An estimated 1.2 million cases/year in approximately 100 countries worldwide suffer from different forms of CL. More than 90% of CL cases occur in the Americas and Eastern Mediterranean regions. Afghanistan, Algeria, Brazil, Colombia, Iraq, Pakistan, and Syria report more than 80% of new CL cases worldwide. Since 2010, the World Health Organization has insisted on the need to work on products that become alternatives for the treatment of LC, especially in products that can be applied topically because with them the probability of systemic toxicity is lower, increasing patient safety.

Currently, it is recommended to apply local treatments for patients with localized LC, either with pentavalent antimonials administered intralesionally or with thermotherapy. Among the options for topical treatment are natural products that have been, are and will be of utmost importance as sources of medicinal agents. In addition to natural products that have found direct medicinal applications as pharmaceutical entities, many others can serve as chemical models or templates for the design, synthesis and semi-synthesis of novel substances for the treatment of human diseases.

Arnica montana L. is a plant with anti-emollient, healing, anti-inflammatory, analgesic and antineuralgic properties; it is included in the Colombian vademecum of medicinal plants.

In a randomized phase Ib/II clinical trial conducted in patients with localized LC in Colombia, 100% (per protocol analysis) and 92% (intention-to-treat analysis) efficacy was demonstrated, with no adverse effects other than those expected such as erythema, burning, pain or itching.

By demonstrating that arnica tincture is effective and safe, and that A. montana flower extracts in different preparations (topical solutions, tinctures, liniments, ointments or gels) are approved by the European Medicines Agency and are included in the vademecum of Colombian plants issued by the Ministry of Social Protection of Colombia in 2008, the present study aims to establish the safety and efficacy of arnica tincture as an alternative for the topical treatment of localized LC compared to a currently available local therapeutic alternative: intralesional pentavalent antimonials.