High-Frequency Ultrasound Monitoring of Cutaneous Leishmaniasis During Treatment

Patients with cutaneous leishmaniasis will be enrolled consecutively in a prospective, single-center observational cohort at the Leishmaniasis Outpatient Clinic, Dermatology Service, University Hospital of Brasilia (HUB), Brazil. The treating clinicians determine antiparasitic treatment according to routine care; the research protocol does not assign treatment.

The diagnosis will follow an established composite reference standard based on a compatible clinical presentation and parasitological confirmation (for example, direct smear, culture, molecular detection, or amastigotes identified on histopathology), or corroborating non-parasitological findings when parasitological confirmation is unavailable. Histopathological specimens obtained at baseline as part of diagnostic care are available for retrospective review and correlation with clinical and ultrasonographic findings.

Serial high-frequency ultrasound using a Clarius L20 handheld linear scanner (8-20 MHz), including B-mode and color Doppler examination, will assess lesion morphology, echogenicity, dermal and hypodermal thickness, and vascularity. The ultrasound schedule is at days 0, 15, 30, 45, and 90 from initiation of treatment. Clinical follow-up will occur during treatment and for up to 12 months from treatment initiation. No investigational drugs or treatment allocation are part of this observational study.

The primary endpoint is clinical cure at three months following completion of treatment, assessed by clinical examination. Secondary analyses will characterize longitudinal ultrasound changes, the relationship of baseline clinical and histopathological findings with ultrasound features, persistence of sonographic abnormalities at initial clinical cure assessment, and exploratory association of sonographic characteristics with subsequent relapse. Ultrasound findings will not themselves define clinical cure or demonstrate parasite viability.