New World cutaneous leishmaniasis — DTM&H MCQ

Correct answer: C — Sodium stibogluconate 20 mg/kg/day for 20 days

The correct answer is C, sodium stibogluconate 20 mg/kg/day for 20 days. This patient has New World cutaneous leishmaniasis acquired in Guatemala, where Lutzomyia sandflies transmit Leishmania (Viannia) species, chiefly L. braziliensis, which carries a recognised risk of late mucocutaneous progression (espundia) even after the primary cutaneous lesion heals. An ear ulcer (chiclero ulcer) is a classic presentation of New World CL in Central America. Because Viannia subgenus infection cannot be excluded on clinical grounds alone, systemic pentavalent antimonial therapy is required rather than local or topical treatment, as only systemic drug levels adequately eliminate parasites that may seed nasopharyngeal mucosa. Sodium stibogluconate at 20 mg/kg/day for 20 days is the standard systemic antimonial regimen used for this indication. Why the other options are wrong: A. Topical paromomycin ointment for 20 days: this achieves only local cure of the skin lesion and does not reach systemic or mucosal tissue, so it does not prevent metastatic mucosal spread from Viannia species. E. Oral ketoconazole for 28 days: azoles have variable and generally poor efficacy against New World Leishmania species, particularly L. braziliensis, and are not recommended where mucocutaneous risk exists. D. Cryotherapy every 3 weeks: this is a destructive local modality for Old World CL with low mucocutaneous risk (e.g. L. major) and has no systemic antileishmanial effect to prevent mucosal disease. B. Observation and wound care: untreated Viannia infection can progress years later to destructive mucosal disease, so observation alone is inappropriate once biopsy confirms amastigotes in a high-risk species region. Key point: any New World CL where Leishmania (Viannia) cannot be excluded requires systemic pentavalent antimonial therapy, because only systemic treatment prevents delayed mucocutaneous progression that topical or destructive local therapies cannot address.

Reference: DermNet NZ, Sodium stibogluconate (Pentostam) for leishmaniasis: treatment dosing 20 mg/kg/day for cutaneous leishmaniasis for 20 days, https://dermnetnz.org/topics/sodium-stibogluconate (clinical reference used in UK practice, consistent with UK Hospital for Tropical Diseases and WHO pentavalent antimonial dosing for New World CL with mucocutaneous risk)