Leprosy

: A chronic granulomatous infection caused by a bacillus (bacterium) that affects various areas of the body, particularly the skin and nerves. (Granulomas are inflammatory nodules that are usually small, granular, firm, and persistent.) The bacillus responsible for leprosy is called Mycobacterium leprae (or M. leprae, for short). M. leprae is an obligate parasite. By "obligate" is meant that it has to live within cells. There it is able to withstand the onslaught of enzymes and other forces through its resistant waxy coat and its association with lowered cellular immunity. M. leprae multiplies very slowly within the body. For thousands of years, leprosy was one of the world’s most feared communicable diseases, because the skin and nerve damage often led to terrible disfigurement and disability. (In ancient sources such as the Bible, the term "leprosy" encompassed various cutaneous diseases, especially those of a chronic or contagious nature, probably including psoriasis.) The typical early signs of leprosy are flat or slightly raised patches on the skin, usually single but at most three, well demarcated, non-itching, and hypopigmented or reddish. Patients feel nothing in the affected area. This sensory loss is very important for diagnosis because bacilli are often undetectable in skin smears. The classic clinical form of leprosy is thus called anesthetic leprosy. It chiefly affects nerves. The condition is marked initially by hyperesthesia (excess sensation) succeeded by anesthesia (lack of feeling) and by paralysis, ulceration, and various other problems, ending horribly in gangrene and self-mutilation. People without significant defenses against the bacillus tend to develop this form of multibacillary leprosy, while those with a stronger immune system come down with paucibacillary leprosy which is relatively harmless and as a rule non-infectious. Although the mode of transmission of leprosy remains uncertain, most investigators think that M. leprae is usually spread from person to person in respiratory droplets. The exact incubation period of leprosy is unknown — it can vary from three months to 40 years. The disease most often strikes young people between 10 and 20 years of age, men more often than women. Groups at risk include close contacts with patients with untreated, active, predominantly multibacillary disease, and persons living in countries with highly endemic disease. One to two million persons are permanently disabled as a result of leprosy. In the year 2000, 738,284 new cases of leprosy were identified. India accounts for almost four-fifths (nearly 80%) of all cases of leprosy in the world. Half of the world's leprosy cases are now found in the five Indian states of Bihar, West Bengal, Uttar Pradesh, Madhya Pradesh and Orissa. A major susceptibility gene for leprosy in India has been mapped to chromosome region 10p13.

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1. A chronic granulomatous infection caused by Mycobacterium leprae affecting the cooler body parts, especially the skin, peripheral nerves, and testes. L. is classified into two main types, lepromatous and tuberculoid, representing extremes of immunologic response. 2. A name used in the Bible to describe various cutaneous diseases, especially those of a chronic or contagious nature, which probably included psoriasis and leukoderma. SYN: Hansen disease. [G. lepra, from lepros, scaly]

- anesthetic l. a form of l. chiefly affecting the nerves, marked by hyperesthesia succeeded by anesthesia, and by paralysis, ulceration, and various trophic disturbances, terminating in gangrene and mutilation. SYN: Danielssen disease, Danielssen-Boeck disease, dry l., trophoneurotic l..

- borderline l. a form of l. that is very unstable immunologically; the cutaneous nerves frequently contain bacilli, but the lepromin test is usually negative; cutaneous lesions are composed of flat bands or plaques. SYN: dimorphous l..

- dimorphous l. SYN: borderline l..

- dry l. SYN: anesthetic l..

- histoid l. a form of lepromatous l. with lesions microscopically resembling dermatofibroma or other spindle-celled tumors.

- indeterminate l. a transitory form of l. in which the immunologic status is not yet formed, and the histologic and clinical features are not yet characteristic of any of the major types of l..

- lepromatous l. a form of l. in which nodular cutaneous lesions are infiltrated, have ill-defined borders, and are bacteriologically positive; the lepromin test is negative, i.e., the immunologic mechanism of the patient is not responsive to the Mycobacterium leprae infection.

- Lucio l. an acute form occurring in pure diffuse lepromatous l. presenting irregularly shaped, intensely erythematous, tender plaques, especially of the legs, with tendency to ulceration and scarring. SYN: Lucio l. phenomenon.

- macular l. a form of tuberculoid l. in which the lesions are small, hairless, and dry, and are erythematous in light skin and hypopigmented or copper-colored in dark skin.

- mutilating l. a late stage of anesthetic l..

- nodular l. SYN: tuberculoid l..

- smooth l. SYN: tuberculoid l..

- trophoneurotic l. SYN: anesthetic l..

- tuberculoid l. a benign, stable, and resistant form of the disease in which the lepromin reaction is strongly positive and in which the lesions are erythematous, insensitive, infiltrated plaques with clear-cut edges. SYN: nodular l., smooth l..

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lep·ro·sy 'lep-rə-sē n, pl -sies a chronic disease caused by infection with an acid-fast bacillus of the genus Mycobacterium (M. leprae) and characterized by the formation of nodules on the surface of the body and esp. on the face or by the appearance of tuberculoid macules on the skin that enlarge and spread and are accompanied by loss of sensation followed sooner or later in both types if not treated by involvement of nerves with eventual paralysis, wasting of muscle, and production of deformities and mutilations called also hansenosis, Hansen's disease, lepra see LEPROMATOUS LEPROSY, TUBERCULOID LEPROSY

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(Hansen's disease)

n.

a chronic disease, caused by the bacterium Mycobacterium leprae, that affects the skin, mucous membranes, and nerves. It is confined mainly to the tropics and is transmitted by direct contact. After an incubation period of 1-30 years, symptoms develop gradually and mainly involve the skin and nerves. Lepromatous (multibacillary) leprosy is a contagious steadily progressive form of the disease characterized by the development of widely distributed lumps on the skin, thickening of the skin and nerves, and in serious cases by severe numbness of the skin, muscle weakness, and paralysis, which leads to disfigurement and deformity. Tuberculosis is a common complication. Tuberculoid leprosy is a benign, often self-limiting, form of leprosy causing discoloration and disfiguration of patches of skin (sparsely distributed) associated with localized numbness. Indeterminate leprosy is a form of the disease in which skin manifestations represent a combination of the two main types; tuberculoid and indeterminate leprosy are known as paucibacillary leprosy.

Like tuberculosis, leprosy should be treated with a combination of antibacterial drugs, to overcome the problem of resistance developing to a single drug; the WHO advocates a combination of rifampicin and dapsone for six months to treat paucibacillary leprosy and these drugs with the addition of clofazimine for multibacillary leprosy, this multidrug therapy (MDT) to be continued for two years. Reconstructive surgery can repair some of the damage caused by the disease. A vaccine is being developed and tested.

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lep·ro·sy (lepґrə-se) [Gr. lepros scaly, scabby, rough] a slowly progressive, chronic infectious disease caused by Mycobacterium leprae and characterized by granulomatous or neurotrophic lesions in the skin, mucous membranes, nerves, bones, and viscera, with a broad spectrum of clinical symptoms. Two principal types are distinguished: lepromatous leprosy and tuberculoid leprosy, with gradations between them known as borderline leprosy. Called also Hansen disease. leprotic, leprous adj