Classification of leprosy
Last reviewed: 23.04.2024
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According to the classification adopted at the 6th International Congress on Leprosy in Madrid in 1953, the following forms of leprosy are distinguished: lepromatous, tuberculoid, undifferentiated and borderline (dimorphic). The first two types of leprosy are recognized as polar.
Lepromatous type - the most severe form of the disease, highly contagious, difficult to treat. The skin, mucous membranes, lymph nodes, visceral organs, eyes, peripheral nerves are affected. A typical lesion of the skin is diffuse and limited infiltration (lepromatous infiltration and leprom). A bacterioscopic examination of scrapings from skin lesions and nasal mucosa reveals a large number of pathogens. Intradermal lepromine sample is negative. When histological examination of lesions is determined lepromatous granuloma, the main cellular elements of which are leprosy Virkhov cells - macrophages with a "foamy" cytoplasm, containing mycobacteria leprosy.
Tuberculoid type of leprosy is characterized by a lighter course of the disease, the results of treatment are better. The skin, peripheral nerves, lymph nodes are affected. Typical skin lesions are tuberculoid rashes. In scrapings from skin lesions and mucous membrane of the nose, mycobacterium leprosy is not detected. Lepromine test positive. In the histological examination of lesions, granuloma is determined, consisting mainly of epithelioid cells surrounded by lymphoid ones. In the center of the granuloma there are giant cells like Langhans.
The undifferentiated type of leprosy is a relatively benign form of the disease, characterized by damage to the skin and peripheral nerves. The defeat of the skin is expressed in the appearance of flat erythematous spots. At bacterioscopic examination of scrapings from skin lesions and nasal mucosa, as a rule, the causative agent is not detected. The reaction to lepromin can be negative or positive, depending on the development trend of the infectious process (this or that polar type of leprosy). Histologically, lymphocytic infiltration of lesions is observed.
Border (dimorphic) leprosy is a malignant form of the disease, characterized by damage to the skin, mucous membranes and peripheral nerves. Clinical signs of skin lesion are characteristic of both lepromatous and tuberculoid types of leprosy. At bacterioscopic examination of scrapings from skin lesions, mycobacterium leprosy is found in large quantities, in scrapings from the mucous membrane of the nasal cavity - not always. The lepromine sample is usually negative. Histological examination of lesions reveals a granuloma consisting of cellular elements characteristic of both one and the other polar type of leprosy.
D. Ridley and W. Jopling (1962, 1966) proposed the classification of leprosy, which includes five main groups (tuberculoid type, lepromatous type, borderline tuberculoid group, borderline leprosy, borderline-lepromatous group) and two additional groups (subpolar lepromatosis and undifferentiated leprosy ). The X International Leprosy Congress (Bergen, 1973) and the WHO Expert Committee on leprosy (WHO, 1982) recommend using this classification. At the same time, according to the WHO Expert Committee on leprosy, the Madrid classification of leprosy should also be widely used (WHO, 1982).
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