Cutaneous leishmaniasis responds to daylight-activated photodynamic therapy: proof of concept for a novel self-administered therapeutic modality

BACKGROUND: Cutaneous leishmaniasis (CL) is endemic in Israel, with hundreds of new cases reported in recent years. Photodynamic therapy (PDT) is highly effective for treatment of CL, but requires equipment available only at specialized centres. Daylight-activated PDT (DA-PDT) abolishes the need for artificial light sources and allows the patient to administer the treatment with no professional assistance.

OBJECTIVES: The objective of this single-centre, open study was to establish proof of concept for the efficacy of DA-PDT in the treatment of CL using clinical, microbiological and molecular clearance as outcome measures.

METHODS: Thirty-one patients with CL (11 Leishmania major and 20 Leishmania tropica) underwent DA-PDT. Fourteen patients were treated in the hospital garden under professional supervision and 17 patients underwent DA-PDT as a self-administered treatment modality at home. Following application of a thick layer of 16% methyl aminolaevulinate and 30-min occlusion, the lesions were exposed to daylight for 2·5 h. Treatment sessions were repeated at weekly intervals until clinical and microbiological cure. Control lesions were either treated with cryotherapy or left untreated.

RESULTS: The overall cure rate for DA-PDT was 89% (intention-to-treat cure rate 77%); this was 86% for the hospital-based treatment group and 92% for the self-administered group.

CONCLUSIONS: DA-PDT proved to be effective in the treatment of CL caused by L. major and L. tropica. More patients were treated according to a self-administered protocol, suggesting that DA-PDT can be adopted even in technologically deprived countries where the majority of Leishmania infections are encountered.