A chronic communicable infection which is a principal or polar form of leprosy. This disorder is caused by mycobacterium leprae and produces diffuse granulomatous skin lesions in the form of nodules, macules, or papules. The peripheral nerves are involved symmetrically and neural sequelae occur in the advanced stage. The disease is Monarch Disease Ontology identifier MONDO_0005127 (lepromatous leprosy). Also known as: lepromatous leprosy [type L], type L leprosy.