The ulcer usually heals spontaneously over six months. L. viannia infection is associated with lesions on the skin or mucous membranes, which may be multiple and may become very large, especially when accompanied by bacterial superinfection. Cutaneous lesions caused by L. braziliensis are much less likely to heal spontaneously than those caused by L. mexicana . The lesions sometimes spread up the lymphatic vessels of the arms or legs or extend locally and involve mucous membranes. Often, the infection metastasizes to the nasal or oral mucosa after an intervening period of months to years.
Metastatic lesions can erode the nasal septum or the hard palate or soft palate.
Some patients may die of malnutrition or bacterial infection. Diffuse cutaneous leishmaniasis occurs in parts of Ethiopia, Venezuela, Brazil, and the Dominican Republic. Leishmanial organisms abound in the lesions. Patients with this form of leishmaniasis have a deficiency of cell-mediated immunity, which is similar to the defective immunity that occurs in patients with lepromatous leprosy. Alternatively, the diagnosis can be made by culturing amastigotes on NNN medium inoculated with lesion material.