These are the cases that are usually depicted in pictures. The bacilli in lepromatous leprosy are present in large numbers in the blood stream, skin, and internal organs. Other organs involved are the bone marrow, lymph nodes, eyes, larynx, muscles, liver and spleen. 11 bacilli can be present in an individual infected with this type of leprosy. LL invades the nasal bones directly, leading to the collapse of the nose, as well the phalangeal bones, which leads to the destruction of the fingers and toes.
Infertility happens as a result of testicular involvement, and the breasts become enlarged.
The development of the lesions can take as long as two to four years. The leisons have distinct and elevated edges and show a loss of tactile sensation. There is also changes in pigmentation, impairment of sweating and reduced hair growth. The lesions may show central areas of healing. Biopsies of the lesions show a heavy granulomatous infiltrate of lymphocytes, epitheliod cells and non-vacuolated giant cells, but bacilli are usually never seen.