Editorial Commentary: Local Treatments for Cutaneous Leishmaniasis

Abstract

Cutaneous leishmaniasis (CL) is an infection caused by various species of Leishmania protozoa, which are usually transmitted by the bite of various species of phlebotomine sandflies [1]. It is a “neglected tropical disease” that causes significant morbidity and social stigmatization and also occurs in subtropical regions such as southern Europe and the southern United States. Its clinical presentations and natural history vary considerably, and although nearly all cases will eventually heal spontaneously, this can take more than a year and be complicated by secondary bacterial infections, lymphatic involvement, local recurrences, and mucosal leishmaniasis due to Leishmania (Viannia) braziliensis complex infections in certain New World countries. Laboratory diagnosis requires specialist parasitology and molecular biology techniques, and numerous local and systemic treatment options are available. Recent studies [2, 3] offer a timely reminder of the value of local (topical or intralesional) treatments for CL, when most research is focused on systemic (oral or parenteral) treatments instead. Morizot et al [2] show how national treatment guidelines and expert advice can optimize the use of simple wound care only or local treatment for a wide range of CL infections in travelers with impressive results. Overall, 62% of cases were treated this way and cure rates within 60 days of starting treatment were 92% for wound care only and 79% for cryotherapy plus intralesional antimony, compared to 60% for systemic treatments. The majority of cases had a good prognosis and were suitable for nonsystemic treatment according to the national guidelines, whereas those with a worse prognosis were more likely to be given systemic treatment, and so there is obvious selection bias. However, some centers would have treated all of these cases with systemic treatments at higher cost and with more adverse effects and so the results remain valuable. Interestingly, no patients seem to have withdrawn due to the transient but severe pain sometimes caused by intralesional treatment (or other forms of cryotherapy) that may dissuade physicians from using such techniques. Systemic treatments for CL are often preferred for several reasons, including the fact that most new therapies for CL are derived from those used for visceral leishmaniasis, which are inevitably systemic in nature. Local treatments are also more difficult to evaluate due to problems in standardizing the dose given during administration of a topical or intralesional drug. Even when local treatments are known to be effective, there may be problems in the provision of therapies such as intralesional pentavalent antimonial (SbV) drugs (sodium stibogluconate or meglumine antimoniate), cryotherapy, topical paromomycin (aminosidine), and thermotherapy. Overall, our healthcare systems often make it