Successful treatment of facial cutaneous leishmaniasis with photodynamic therapy

Sir,

Leishmaniasis is a widespread protozoan zoonosis transmitted by sandflies that can cause a wide range of manifestations. Cutaneous leishmaniasis is the most common form, usually presenting as a papule on exposed skin that enlarges and finally ulcerates. Therapies for cutaneous leishmaniasis are limited and the systemic treatments available are hampered by toxicity and parasite resistance. As an alternative, photodynamic therapy has been reported to be a safe and effective treatment for cutaneous leishmaniasis.^1,2

An otherwise healthy woman in her 60s, presented to the dermatology department with a solitary, asymptomatic, violaceous papule on her left cheek that enlarged slowly in the past four months [Figure 1a]. Travel history was significant for a trip to Peru, mainly the urban areas, one year prior to the current complaint. Dermoscopic examination showed a symmetric mildly pigmented lesion, with some comedo-like openings, white interfollicular structures and a few focused telangiectatic vessels [Figure 1b]. Reflectance confocal microscopy (Vivascope 3000, Mavig, Germany) revealed dilated follicular openings in the epidermis, marked adnexal structures and dense material in the superficial dermis with inflammatory cells and prominent horizontal vessels. With the suspected diagnosis of cutaneous leishmaniasis, a punch biopsy was performed. Histopathologic examination showed dilatation of the follicular infundibulum associated with a mixed inflammatory infiltrate in the dermis. Non-necrotizing granulomas and intracytoplasmic structures compatible with amastigotes were also observed, confirming the diagnosis of cutaneous leishmaniasis [Figures 1d-f]. After discussing treatment options with the patient, local therapy was chosen due to the potential side effects of systemic alternatives. The patient was treated with three courses of photodynamic therapy three weeks apart. Carbon dioxide (CO₂) fractional laser was used as a drug delivery technique to improve the absorption of the photosensitizer (wavelength 10.600 nm, energy density 31.8 J/cm, coverage 8%, power 30W, beam size 500 μm). This method increases the therapeutic efficacy of photodynamic therapy, shortening the incubation time and contributing to a reduction in the number of photodynamic therapy sessions.³ Subsequently, topical 7.8% 5-aminolevulinic acid was applied and occluded for two hours. The lesion was then irradiated using a red light-emitting diode lamp (BF-RhodoLED^®, 635 nm, 37 J/cm). After the third session, the lesion showed a complete clinical response with excellent cosmetic results [Figure 1c]. Photodynamic therapy was well tolerated and the patient only experienced mild erythema and a transient burning sensation as side effects. To confirm the treatment response, reflectance confocal microscopy was performed which demonstrated a regular honeycomb pattern with unremarkable dermal features two months later. The patient has not presented with a relapse of the lesion during six months of follow-up.

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Figure 1:

(a) The initial clinical presentation showed a violaceous plaque on the left cheek. (b) Dermoscopy revealed superficial scales, orange comedo-like openings and white interfollicular structures over an erythematous background (DL100, 3Gen, California, ×10). (c) Clinical resolution after 3 sessions of photodynamic therapy. (d, e) The flattened epidermis marked dilation of the follicular infundibulum and a mixed dermal inflammatory infiltrate consisting primarily of lymphocytes, plasma cells and histiocytes (Hematoxylin and eosin, ×20) (Hematoxylin and eosin, ×40). (f) Scattered intracytoplasmic structures (arrows), consistent with leishmania amastigotes (Hematoxylin and eosin, ×100)

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Although cutaneous leishmaniasis is usually a self-limited infection, treatment is advised to avoid ulceration, scarring or disease progression. Cutaneous leishmaniasis may constitute a therapeutic challenge since evidence for optimal treatment is ambiguous.² Systemic drugs have potential adverse effects and the risks and benefits of the available therapies should be discussed with every patient. In recent years, photodynamic therapy has been introduced as a safe and effective alternative therapy for cutaneous leishmaniasis, with mild side effects and excellent cosmetic outcomes.¹ It has been reported as a successful treatment for cutaneous leishmaniasis in at least 75 cases, most of which are due to L. donovani, L. major and L. tropica, and some with complex cutaneous leishmaniasis involving the face [Table 1]. Asilian et al.¹ compared photodynamic therapy versus topical paromomycin and placebo, showing a complete response in 93.5% versus 41.3% and 13.3% of lesions respectively.¹ Photodynamic therapyprotocols for treating cutaneous leishmaniasis have not yet been standardized. In most reported cases; topical aminolevulinic acid or methyl aminolevulinate were applied as photosensitizers, followed by incubation and red light irradiation, with three to eight weekly sessions. Enk et al.⁴ assessed the use of daylight-activated photodynamic therapy in 31 patients with cutaneous leishmaniasisand reported an overall cure rate of 89%. This modality requires almost no equipment and could be performed in rural areas and technologically underdeveloped countries.⁴ Although the response to treatment should be assessed by clinical criteria, testing for parasites is often performed.² Despite the limitation of in-depth evaluation, reflectance confocal microscopy can help rule out common tumours of the face as it can show findings more suggestive of cutaneous leishmaniasis such as dilated linear and comma-shaped vessels, follicular plugging and the presence of multinucleated giant cells in the superficial dermis.⁵ Reflectance confocal microscopy, along with dermoscopy, could be a useful, non-invasive tool, not only to support the diagnosis of cutaneous leishmaniasis but also to monitor healing, avoiding unnecessary biopsies or additional photodynamic therapy sessions.

Photodynamic therapy is an effective and well-tolerated therapeutic option for the treatment of simple cutaneous leishmaniasis. The use of fractional CO₂ laser as a drug-delivery method could shorten the number of photodynamic therapy sessions needed. Further studies are needed to establish the optimal photodynamic therapy protocol for treating cutaneous leishmaniasis and evaluate its use in cosmetically relevant regions. Reflectance confocal microscopy is a promising complementary tool in the diagnosis and follow-up of patients with cutaneous leishmaniasis.