- Human pathology

Home > D. General pathology > Infectious diseases > lepromatous leprosy

lepromatous leprosy

ICD-10 A30.4 and ICD-10 A30.5

Tuesday 23 March 2010

Multibacillary leprosy

Definition: Lepromatous leprosy is a form of leprosy. It is a skin condition consisting of pale macules.


- Lepromatous leprosy

- Encased neurovascular bundle. Lepromatous leprosy.

Lepromatous leprosy is associated with symmetric skin lesions, nodules, plaques, thickened dermis, and frequent involvement of the nasal mucosa resulting in nasal congestion and epistaxis (nose bleeds) but typically detectable nerve damage is late.

Multibacillary leprosy in WHO classification. Borderline lepromatous leprosy ("BL") and lepromatous leprosy ("LL") in Ridley-Jopling classification. ICD-10 A30.4 and ICD-10 A30.5

Lepromin test is negative. Immune target is plasmid inside bacillus (Th2).


In the lepromatous form of leprosy, a diffuse infiltrate of foamy macrophages is present in the dermis below a subepidermal grenz zone.

An enormous number of acid-fast bacilli develop within the foamy macrophages, singly or in clumps, called globi.

Lymphocytes are scant, and giant cells are typically absent. Numerous bacilli invade the nerves, but these are fairly well preserved with little infiltrate.

Nodular, or dermatofibromalike lesions in lepromatous leprosy, referred to as histoid leprosy, result in a diffuse fascicular arrangement of spindled cells in the dermis admixed with foamy macrophages that contain numerous bacilli.v

Lymph nodes show aggregation of foamy macrophages in the paracortical (T-cell) areas, with enlargement of germinal centers. In advanced disease, aggregates of macrophages are also present in the splenic red pulp and the liver.

The testes are usually extensively involved, with destruction of the seminiferous tubules and consequent sterility.

Clinical synopsis

Early cutaneous lesions consist mainly of pale macules.

Late infiltrations are present with numerous bacilli. Macular lesions are small, diffuse, and symmetric. The skin may be smooth and shiny, but skin changes do not occur in lepromatous leprosy until late in the course. Therefore, early lepromatous leprosy lesions have little or no loss of sensation, nerves are not thickened, and sweating is normal. Nerve loss is slow and progressive.

Hypoesthesia occurs first over extensor surfaces of the distal extremities, followed by weakness in the same areas.

Alopecia affects the lateral aspects of the eyebrows (madarosis), spreading to the eyelashes and then the trunk. Scalp hair remains intact.

Lepromatous infiltrations can be diffuse, can occur as nodules (called lepromas), or can be plaques. The diffuse type results in the thickened skin appearance of a leonine facies. Neuritic lesions are symmetric and slow to develop.

Eye involvement occurs, causing pain, photophobia, decreased visual acuity, glaucoma, and blindness.

Nasal infiltration can cause a saddle-nose deformity and impaired olfaction. Hoarseness ("leprous huskiness") and stridor are a result of laryngeal involvement.

Oral lepromas, usually located on the hard and soft palate, uvula, tongue ("cobblestoning"), lips, and gums, can progress to necrosis and ulceration. Tissue destruction may result.

Infiltration of the helix or megalobule (elongation and wrinkling of the earlobe) may occur.

Lymphadenopathy and hepatomegaly can result from organ infiltration.

Aseptic necrosis and osteomyelitis can occur with repeated trauma after joint invasion.

Macular, papular, or nodular lesions form on the face, ears, wrists, elbows, and knees. With progression, the nodular lesions coalesce to yield a distinctive leonine facies. Most skin lesions are hypoesthetic or anesthetic. Lesions in the nose may cause persistent inflammation and bacilli-laden discharge.

The peripheral nerves, particularly the ulnar and peroneal nerves where they approach the skin surface, are symmetrically invaded with mycobacteria, with minimal inflammation. Loss of sensation and trophic changes in the hands and feet follow the nerve lesions.

Brawny edema of the lower extremities is a late finding.

Unlike the other types of leprosy, lepromatous leprosy cannot convert back to the less severe borderline leprosy or tuberculoid leprosy.


Lepromatous leprosy involves the skin, peripheral nerves, anterior chamber of the eye, upper airways (down to the larynx), testes, hands, and feet. The vital organs and central nervous system are rarely affected, presumably because the core temperature is too high for growth of Mycobacterium leprae.

Lepromatous lesions contain large aggregates of clear lipid-laden macrophages (lepra cells or Hansen cells), often filled with masses of acid-fast bacilli (globi).

The failure to contain the infection and to form granulomas reflects failure of the TH1 response.

See also

- leprosy (Hansen disease )