Contributor: Gordon K. Klintworth
Lepromatous leprosy is a Mycobacterium infection caused by Mycobacterium leprae. There is little if any cell-mediated response to the pathogen. The disease is most prevalent in the tropics and subtopics (Africa, Mexico, Central America, Middle East, India, Southern Europe, China, Southeast Asia). It also occurs in the Southern United States. The skin and peripheral nerves are affected most often, but the respiratory system, vascular endothelium and reticuloendothelial system may be involved. Lesions of the cornea may be prominent. Lepromatous leprosy is characterized by nodular and diffuse lesions with vast numbers of bacteria within macrophages. The affected individuals have a negative lepromin test because of anergy and the disease is rapidly progressive and fatal. Lepromatous leprosy needs to be differentiated from other conditions associated with a xanthogranulomatous reaction (xanthogranuloma).