Leprosy

Definition:
Leprosy is an infectious disease that has been known since biblical times. It is characterized by disfiguring skin sores, peripheral nerve damage, and progressive debilitation.
Alternative Names:
Hansen's disease
Causes, incidence, and risk factors:
Leprosy is caused by the organism Mycobacterium leprae . It is not very contagious (difficult to transmit) and has a long incubation period (time before symptoms appear), which makes it difficult to determine where or when the disease was contracted. Children are more susceptible than adults to contracting the disease.
Leprosy has two common forms, tuberculoid and lepromatous, and these have been further subdivided. Both forms produce sores on the skin, but the lepromatous form is most severe, producing large, disfiguring nodules (lumps and bumps).
All forms of the disease eventually cause peripheral neurological damage (nerve damage in the arms and legs) which causes sensory loss in the skin and muscle weakness. People with long-term leprosy may lose the use of their hands or feet due to repeated injury resulting from lack of sensation.
Leprosy is common in many countries worldwide, and in temperate, tropical, and subtropical climates. Approximately 100 cases per year are diagnosed in the U.S. Most cases are limited to the South, California, Hawaii, and U.S. island possessions.
Effective medications exist, and isolation of victims in "leper colonies" is unnecessary. The emergence of drug-resistant Mycobacterium leprae , as well as increased numbers of cases worldwide, have led to global concern about this disease.
Signs and symptoms
The earliest sign of leprosy is commonly a spot on the skin that may be slightly redder, darker, or lighter than the person's normal skin. The spot may lose feeling and hair. In some people the only sign is numbness in a finger or toe.
If left untreated, leprosy has serious effects on the body, including:
Hands and feet - Leprosy bacteria attack the nerves in the hands and feet and cause them to become numb. A person may get cuts or burns on the numb parts and not know it, leading to infections which cause permanent damage. Fingers and toes may be lost to infection. Serious infections in the feet may require amputation. Paralysis may cause the fingers and toes to curl up permanently.
Eyes - Leprosy bacteria attack the nerves around the eyes causing the loss of blinking reflex (which protects the eye from injury and moistens the surface). The eyes become dry and infected, and blindness may result. Because of numbness of the eye, the person cannot feel dirt or scratches in the eye.
Face - Damage to the internal lining of the nose causes scarring and eventual collapse of the nose.
Diagnosis;
Diagnosis of leprosy is most commonly based on the clinical signs and symptoms. These are easy to observe and elicit by any health worker after a short period of training. In practice, most often persons with such complaints report on their own to the health centre. Only in rare instances is there a need to use laboratory and other investigations to confirm a diagnosis of leprosy.
In an endemic country or area, an individual should be regarded as having leprosy if he or she shows ONE of the following cardinal signs:
skin lesion consistent with leprosy and with definite sensory loss, with or without thickened nerves
positive skin smears
The skin lesion can be single or multiple, usually less pigmented than the surrounding normal skin. Sometimes the lesion is reddish or copper-coloured. A variety of skin lesions may be seen but macules (flat), papules (raised), or nodules are common. Sensory loss is a typical feature of leprosy. The skin lesion may show loss of sensation to pin pick and/or light touch. Thickened nerves, mainly peripheral nerve trunks constitute another feature of leprosy. A thickened nerve is often accompanied by other signs as a result of damage to the nerve. These may be loss of sensation in the skin and weakness of muscles supplied by the affected nerve. In the absence of these signs, nerve thickening by itself, without sensory loss and/or muscle weakness is often not a reliable sign of leprosy. The clinical system of classification for the purpose of treatment includes the use of number of skin lesions and nerves involved as the basis for grouping leprosy patients into multibacillary (MB) and paucibacillary (PB) leprosy.
Positive skin smears:
In a small proportion of cases, rod-shaped, red-stained leprosy bacilli, which are diagnostic of the disease, may be seen in the smears taken from the affected skin when examined under a microscope after appropriate staining. Leprosy can be classified on the basis of clinical manifestations and skin smear results. In the classification based on skin smears, patients showing negative smears at all sites are grouped as paucibacillary leprosy (PB), while those showing positive smears at any site are grouped as having multibacillary leprosy (MB).A person presenting with skin lesions or with symptoms suggestive of nerve damage, in whom the cardinal signs are absent or doubtful should be called a "suspect case" in the absence of any immediately obvious alternate diagnosis . Such individuals should be told the basic facts of leprosy and advised to return to the centre if signs persist for more than six months or if at any time worsening is noticed. Suspect cases may be also sent to referral clinics with more facilities for diagnosis.
Treatment:
Medications used to eliminate the microorganism and to reduce symptoms include:
Dapsone
Rifampin
Clofazimine
Ethionamide
Aspirin, prednisone, or thalidomide are used for the control of inflammation (e.g., "erythema nodosum leprosum") that may occur with therapy
Possible Complications
Permanent nerve damage
Cosmetic disfigurement
Prevention
Prevention consists of avoiding close physical contact with untreated people. People on long-term medication become noninfectious (they do not transmit the organism that causes the disease).