Leishmania tropica successfully treated with photodynamic therapy

Abstract

Cutaneous leishmaniasis is a neglected tropical infection that inflicts significant morbidity and disfigurement. In Australia it is seen in migrants and returned travellers from endemic areas. Photodynamic therapy is indicated for the treatment of selected non-melanoma skin cancers and premalignant lesions. However, it has also been successful as an alternative off-label therapy for the management of cutaneous leishmaniasis. We present the case of an otherwise well 29-year-old man from Pakistan who presented with a rapidly expanding exophytic and crusted plaque on the dorsum of the nose extending into the distal nares (Fig. 1a). Three months before migrating to Australia he noted an erythematous papule, which he attributed to an insect bite, that enlarged rapidly. His most significant concern was social embarrassment and stigma in the context of his new job working in customer service. A punch biopsy was performed that confirmed a clinical diagnosis of cutaneous leishmaniasis. He received 3 weeks of oral fluconazole (200 mg daily) with no change, and hence was referred to the local tertiary dermatology service for consideration of alternative management strategies. The punch biopsy demonstrated granulomatous inflammation, with admixed neutrophils occupying the full thickness of the dermis. Numerous parasitised histiocytes were noted in the superficial dermis, consistent with leishmaniasis. A polymerase chain reaction test of the tissue confirmed it was Leishmania tropica, a subspecies of Old World cutaneous leishmaniasis. Cutaneous infection caused by L. tropica is recognised as a self-healing condition. However, due to the cosmetically sensitive site and considerable morbidity from this condition, treatment was considered. Intralesional antimonial therapy is recommended, however it is not uniformly available in Australia. Further, due to the failure of azole medications, photodynamic therapy was chosen to be trialled. Photodynamic therapy was administered approximately weekly (range 6–8 days due to availability), as per the treatment interval used by other case series of this treatment modality. The adherent crust was removed with gentle curettage, a 1-mm thick layer of methyl aminolevulinate (16% cream) was applied to the affected area along with a 5-mm margin and then occluded for 3 h, following which 8 min of continuous 630-nm red light was directed at the area. Paracetamol (1 g) was given prior to the procedure and it was tolerated well. At the first review (day 8), a dramatic improvement was seen (Fig. 1b). Prior to the fourth and final treatment, the patient’s skin had almost completely normalised (Fig. 1c) and he was satisfied with the outcome. To maximise inflammation and thus eradicate the amastigotes and to reduce the risk of recurrence, a further three photodynamic therapy sessions were performed at weekly intervals, in accordance with previously effective regimens, with an exceptionally good cosmetic outcome. After the photodynamic therapy sessions the patient was lost to follow up and could not be contacted. Apart from antimonials and azoles, other local therapies, including topical agents and physical therapies such as cryotherapy and radiofrequency-induced heat therapy, may limit the need for systemic treatment and maximise cosmetic results but can be less efficacious and have a higher risk of recurrence. While the mechanism of photodynamic therapy in the treatment of leishmaniasis is yet to be elucidated, there is evolving evidence that a systemic immunomodulatory response is responsible for the clearance of cutaneous