Leprosy
What is Leprosy?
Leprosy is an infectious disease affecting primarily the skin and the nervous system. Most people have a natural immunity to the disease, but usually only prolonged exposure to the causal bacteria may result in active infection. The disease has a long incubation period, which means that the person may be infected long before any symptoms appear. This period may be as long as 3-5 years.Leprosy is more common in the developing countries, and even if detected, most cases go untreated. According to WHO figures, there are about 6 cases of leprosy for every 10,000 Indians. At present, there are over five lakh registered cases of leprosy, mainly from the states of Bihar, Madhya Pradesh and Orissa.
What are the causes?
Leprosy is caused by a bacterium called mycobacterium leprae. It is transmitted from person to person when the infected person coughs or sneezes. It may also be transmitted from an infected person to a susceptible person either through direct physical contact for a prolonged period, or by the use of contaminated clothes and linen.Leprosy has two main forms – tuberculoid and lepromatous. Both forms produce lesions on the skin, but the latter is more severe. Between these two extreme forms, there is borderline or dimorphous leprosy. Patients with borderline disease are far numerous than those with lepromatous or tuberculoid disease.
What are the symptoms?
Leprosy usually starts as a slightly light-coloured patch that may be noticeable on any part of the body. This patch does not have any sensation and the patient is unable to feel pain or temperature in that area. Other symptoms that indicate leprosy include: Lesions on the skin that may not heal for a long time. Loss of sensation in any part of the body. Presence of thickened nerves that can be felt under the skin. Presence of nodules or lumps on the skin especially the face. Muscle weakness in the limbs that makes leprosy patients drag their feet while walking. If left untreated, there is considerable disfiguration of the face and limbs.
How is the diagnosis made?
A thorough physical examination is done. Slit-skin smear from the skin lesions may demonstrate bacteria confirming the diagnosis. Smears made from the secretion in the nose may also show the bacteria. The lepromin skin test is done to classify leprosy. In some cases when the tests are inconclusive, a biopsy may be done from the skin lesions.
What is the treatment?
Though leprosy is an infectious disease, treatment reduces its infectivity to a large extent. Dapsone is the most commonly used drug to treat leprosy, and in about 90 days the patient becomes non-infectious to others. Treatment of leprosy is done by a combination of drugs. This method is called Multi-Drug Therapy (MDT) that includes drugs such as Dapsone, Rifampicin, Ethionamide and Clofazimine . They are effective and have minimal side effects.Some of the side effects of Dapsone include anaemia, liver and kidney impairments, psychosis and allergic rashes. Clofazimine may cause minor side effects like rash and discolouration of the skin and excessive dryness of skin. In such cases, ethionamide may be used as the third drug in MDT.