What is Leprosy

What is Leprosy?

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The Disease

Leprosy is a chronic infectious disease caused by a bacterium. Mycobacterium leprae mainly affects the skin and the peripheral nerves, but also the mucosa of the upper respiratory tract and the eyes. The disease is also called Hansen’s Disease after the scientist who first was the first to see the germ under a microscope in 1873. M. Leprae became the first bacterium identified as causing disease in man.

Classification

Leprosy is classified in two ways. The first, pancibacillary or tuberculoid leprosy, is milder. Patients present one or few lesions, and experience numbness/sensory loss around those lesions. Multibacillary or lepromatous leprosy is associated with the presence of nodular, symmetric skin lesions, plaques, or thickened dermis.

Transmission

The spread of leprosy from person to person is thought to be in respiratory droplets. This puts those who come into close contact with those who are infected, and are in contact with them for a long period of time, at risk for infection. Also, those who live in countries where the disease is highly endemic also are at risk. The risk is severely diminished in today’s society, however, because the transmission of the disease only happens in untreated cases.

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Characteristics of the Disease

Peripheral nerve damage from the bacteria can lead to many different symptoms of leprosy. Sensory loss prevents the feeling of the protective pain sensation that helps to prevent burns, cuts, and exposure to destructive pressures to the hands and feet. This, as well as the loss of productive sweat and oil gland function which leads to dry cracked skin, increase instance of infection in extremities, which leads to destruction and loss of bone.

The atrophy of small muscles in the body also lead to other typical symptoms of the disease. Blindness that can occur from more severe case of the disease can happen because of weakness of the eyelids, which prevents proper protection of the eyes. This small muscles weakness also leads to the “clawing” of the fingers, another typical symptom of the disease.

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This sequence gives a very simplified explanation of how a person with leprosy generally loses bone. It begins when an infected person begins to experience sensory loss in their extremities. The person then does not feel pain when they develop a blister or a lesion, and continued use and strain on and around the lesion leads to infection. This infection worsens and begins to attack the bone, and if untreated over time the infected bone leads to deformities in the foot.