Inoculation occurs after an infected sandfly bites an exposed part of the body (usually the legs, arms, neck, or face). Rare cases have occurred through needle sharing, transfusions, pregnancy, and sexual intercourse. Female sandflies transmit the parasite 7 to 10 days after feeding on an infected person or animal. Once inside the body, the parasites infect the reticuloendothelial system, incubating for weeks to months before symptoms begin to occur.

Complications of leishmaniasis include disfiguring lesions, respiratory compromise, dysphagia, airway obstruction, aspiration, amyloidosis, glomerulonephritis, and cirrhosis. Death usually results from malnutrition, airway obstruction from lesions, aspiration, and secondary infection.

Cutaneous leishmaniasis develops weeks to months after a bite and is detected by the presence of a firm, nontender, nonpruritic, erythematous papule measuring several centimeters with central ulceration, serous crusting, granuloma formation, and a raised erythematous border (volcano sign). Multiple wet or dry lesions may occur with localized lymphangitic spread. Diffuse spreading develops in those with a poor immune response. Healed lesions leave a characteristic retracted, hypopigmented scar.

Leishmaniasis recidivans follows the development of new ulcers and papules over the edge of the old scar, proceeding inward to form a lesion, usually on the cheek. In post-kala-azar dermal leishmaniasis, multiple hypopigmented, erythematous macules develop over the face or trunk, coalescing to form large, raised growths.

Patients with mucocutaneous leishmaniasis may have rhinorrhea, epistaxis, and nasal congestion due to tissue obstruction and perforation. The oral cavity may exhibit granulation, erosion, and ulceration. Involvement of the nasal cartilage produces a parrot’s beak or camel’s nose. Hoarseness indicates laryngeal involvement. Gingivitis, periodontitis, and localized lymphadenopathy may occur; optical and genital mucosal involvement has been reported in severe cases.