Sudanese mucosal leishmaniasis is a chronic infection of the upper respiratory tract and/or oral mucosa caused mainly by Leishmania donovani. The disease occurs in areas of the country endemic for visceral leishmaniasis, particularly among Masalit and other closely related tribes in western Sudan. The condition may develop during or after an attack of visceral leishmaniasis, but in most cases it is a primary mucosal disease. Unlike South American mucocutaneous leishmaniasis, mucosal leishmaniasis in Sudan is not preceded or accompanied by a cutaneous lesion. Pathologically, the lesions show a mixture of macrophages, plasma cells and lymphocytes. An epithelioid granuloma may also be found. Parasites are scanty. Diagnosis is established by demonstration of parasites in smears or biopsies, by culture or animal inoculation, or with the aid of the polymerase chain reaction. Most patients give positive results in the direct agglutination test and leishmanin skin test. Patients respond well to treatment with pentavalent antimony compounds.