Lepromatous leprosy is a form of

leprosy Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damag ...

characterized by pale

macule A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this sy ...

s in the skin. It results from the failure of

Th1 cell The T helper cells (Th cells), also known as CD4+ cells or CD4-positive cells, are a type of T cell that play an important role in the adaptive immune system. They aid the activity of other immune cells by releasing cytokines. They are consider ...

activation which is necessary to eradicate the mycobacteria (Th1 response is required to activate macrophages that engulf and contain the disease). In lepromatous leprosy, TH2 response is turned on, and because of reciprocal inhibition (IL-4; IL-10), the cell-mediated response (TH1) is depressed. Lepromatous leprosy, in contrast to the tuberculoid form of leprosy, is characterized by the absence of

epithelioid cell According to a common point of view epithelioid cells (also called epithelioid histiocytes) are derivatives of activated macrophages resembling epithelial cells. Structure and function Structurally, epithelioid cells (when examined by light mi ...

s in the lesions. In this form of leprosy ''

Mycobacterium leprae ''Mycobacterium leprae'' (also known as the leprosy bacillus or Hansen's bacillus), is one of the two species of bacteria that cause Hansen’s disease (leprosy), a chronic but curable infectious disease that damages the peripheral nerves and ...

'' are found in lesion in large numbers. This is the most unfavorable clinical variant of leprosy. This debilitating form of leprosy begins to spread causing the eyebrows to disappear and spongy tumor like swellings appear on the face and body. The disease attacks the internal organs, bones, joints and marrow of the body resulting in physical degeneration. The result is deformity with loss of feeling in the fingers and toes which eventually fall off. Contrary to popular belief, both forms of leprosy are curable, with the lepromatous form classically treated with antibiotics

dapsone Dapsone, also known as 4,4'-sulfonyldianiline (SDA) or diaminodiphenyl sulfone (DDS), is an antibiotic commonly used in combination with rifampicin and clofazimine for the treatment of leprosy. It is a second-line medication for the treatment a ...

rifampin Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), ''Mycobacterium avium'' complex, leprosy, and Legionnaires’ disease. It is almost always used tog ...

and

clofazimine Clofazimine, sold under the brand name Lamprene, is a medication used together with rifampicin and dapsone to treat leprosy. It is specifically used for multibacillary (MB) leprosy and erythema nodosum leprosum. Evidence is insufficient to suppor ...

for as long as 2–5 years, but if left untreated the person may die up to 20 or 30 years from its inception. Early detection of the disease is of utmost importance, since severe physical and neurological damage are irreversible even if cured (e.g. blindness, loss of digits/limbs/sensation). Early infection is characterized by a well demarcated, usually pale, skin lesion which has lost its hair, and there may be many of these lesions if the infection is more severe (most commonly found on the cooler parts of the body such as the elbows, knees, fingers, or scrotum, as the bacteria thrive in cooler environments). This early presentation is the same for both tuberculous and lepromatous forms of leprosy as they are a spectrum of the same disease (lepromatous being the more contagious and severe form in patients with impaired Th1 response). Disease progression is extremely slow, and signs of infection may not appear for years. Family members of those with the disease, and especially children, are most at risk. The disease is believed to be spread through respiratory droplets in close quarters like its relative ''

Mycobacterium tuberculosis ''Mycobacterium tuberculosis'' (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' has an unusual, waxy coating on its c ...

'', and similarly requires extended exposure to an individual in most situations, so outsiders and healthcare workers are normally not infected (except with the most infective individuals such as those in the most progressed lepromatous forms, as those patients have the highest bacterial loads).

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Bacterium-related cutaneous conditions {{Cutaneous-infection-stub

See also

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