Nodular rash on the face of a man with post kala-azar dermal leishmaniasis (PKDL). This condition is caused by infection with Leishmania sp. protozoan parasites. Leishmania parasites are found in subtropical and tropical regions worldwide and are transmitted to humans through the bite of an infected sandfly. PKDL occurs after kala-azar (visceral leishmaniasis) infection. Kala-azar is the more serious of the two forms of leishmaniasis, resulting in fever, muscle wastage, and, without treatment, sometimes death.